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Research ArticleInfluence Zone Division and Risk Assessment of UnderwaterTunnel Adjacent Constructions

Zhong Zhou Wenyuan Gao Zhuangzhuang Liu and Chengcheng Zhang

School of Civil Engineering Central South University Changsha 410075 China

Correspondence should be addressed to Zhong Zhou 369144091qqcom

Received 25 August 2018 Revised 20 November 2018 Accepted 24 December 2018 Published 15 January 2019

Guest Editor Gerhard-WilhelmWeber

Copyright copy 2019 Zhong Zhou et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Compared with ordinary tunnels the influence analysis of underwater tunnel adjacent constructions is more complicated Atpresent the empirical method used to divide the influence zone of the tunnel adjacent constructions has great uncertainty Soit is of great significance for actual construction and design to determine the influence zone accurately according to theoreticalcalculations In this paper based on the HoekndashBrown nonlinear failure criterion of rock mass and taking seepage factor intoaccount the stress state of rock mass around the underwater tunnel adjacent constructions can be deduced by elastoplastic theoryThen combined with the concept of ldquoloose zone-bearing zonerdquo the influence zone division method of underwater tunnel adjacentconstructions is proposed and it is applied to the analysis of engineering examples Through the deduced theoretical formulas theinfluence zone of underwater tunnel adjacent construction can be divided into extensively strong strong relatively strong weakand noninfluence zones Corresponding the influence zones with the risk levels in the code different control measures are adoptedfor different risk levels which can provide certain guidance for the design and construction of tunnel in practical engineering

1 Introduction

Presently the development of urban subway traffic construc-tion is rapid As the utilization ratio of land resources andbuilding space in the city is gradually improved tunnel con-struction inevitably will be close to existing structures whichmakes tunnel adjacent construction become the key linkin current tunnel design and construction and underwatertunnel is no exception However due to itsmore difficult con-struction more complicated conditions and more stringentrequirements the underwater tunnel adjacent construction isdifferent from ordinary tunnels How to evaluate the impactof underwater tunnel construction on adjacent structures isof great guiding significance for tunnel line selection and siteconstruction

The local and overseas scholars have performed out-standing achievement regarding the influence zone divisionof tunnel adjacent constructions In 1998 Japan made aguideline for the construction of railway highway andelectric power industries which lead to the beginning of thestudy on the influence zone of adjacent construction [1]In recent years the research on the theory of zoning has

been further developed In terms of experimental researchthe team of Chou [2] systematically summarized the localcases of recent construction projects studied the impact ofadjacent construction and proposed the zoning method ofdifferent types of adjacent construction For example whentwo tunnels are parallel (where L is the distance between thetwo tunnels) L lt1D is the strong influence area and 1DleLlt25D is the weak influence area Thereafter most of thestudies are similar Du [3] relied on the tunnel in Shanghaito carry out in situ tests of soil disturbance Based on the soildisturbance data the degree of influence was divided Li et al[4] deduced the disturbed plastic zone of soil under tunnelconstruction based on hole expansion theory The plasticzone was regarded to strong influence zone and the fieldtest and the finite element method were used to verify thisfinding Other scholars conducted further research on thebasis of different engineering test data In terms of numericalsimulation Huang et al [5] used a series of centrifuge modeltests conducted to investigate the effect of deep excavationabove an existing tunnel Xu et al [6] studied the influenceshield tunneling on surround soils through the monitoringin situ and analyzed the soil disturbance by variation of the

HindawiMathematical Problems in EngineeringVolume 2019 Article ID 1269064 10 pageshttpsdoiorg10115520191269064

2 Mathematical Problems in Engineering

stress due to shield tunneling Tao et al [7] calculated thestress of infinite elastic plate by using elastic theory of planestrain in which the stress and the different stress of it onlycaused before metro tunnel excavation were piled up andthen derived ground settlement curve equation from thesolution of infinite elastic plate Huang et al [8] presenteda finite-element parametric study of tunnel behavior causedby nearby deep excavation and investigated the effects ofseveral parameters that may affect the tunnel response Wanget al [9] established a three-dimensional simulation methodthat can fully reflect the whole process of shield tunnelingto study the impact of the adjacent construction to the pilefoundation Liu et al [10] investigated the effects of pipejacking on existing underlying tunnels and analyzed thevertical displacement horizontal displacement and diameterconvergence of the tunnel based on the field observationsAvgerinos et al [11] developed a basic three-dimensional (3D)finite-element (FE) model and discussed changes in hoopforces bending moments and lining deformations of theexiting tunnel due to excavation of the new tunnel Zhanget al [12] presented the deformation analyses of existingsubway tunnels induced by an earth pressure balance (EPB)shield during the process of above-overlapped and down-overlapped crossing tunnels with oblique angles based onthe Shanghai Railway transportation project and in situmonitoring data Hu et al [13] discussed in detail the criteriaandmeasures for controlling the soil and tunnel deformationSharma et al [14] found that the stiffness of the tunnellining has significant influence on the displacement anddistortion of tunnels caused by an adjacent excavation Inworks [15 16] different numerical simulation methods werealso used to evaluate the influence zone of the adjacentconstruction In theoretical deduction the influence zoneof the adjacent construction was often simplified to theelastic mechanics analysis and calculation of double-holeor multihole tunnel excavation Classical solutions are asfollows Peck formation loss model [17] Sagaseta ldquomirrormethodrdquo [18] and Howland [19] infinite circular hole stressfunction Ng et al [20] designed and carried out two three-dimensional centrifuge tests in dry sand to investigate theeffects of a basement excavation on an existing tunnel locatedin two horizontal offsets in relation to the basement Zhao etal [21] determined the additional stress of shield tunneling onthe basis of Mindlin solution of elastic mechanics to evaluatethe influence range Zhang et al [22] used a viscoelastoplasticmodel (VEP model) to simulate the rheologic deformationof soil and studied the behavior of the tunnel underneathexcavation by the new method to discuss the influence ofdifferent factors including excavation area relative distanceand construction procedure Nawel et al [23] used FiniteElement Method to simulate numerically the interactioneffects caused by construction of two parallels tunnels Weiet al [24] presented a method for security discrimination ofadjacent underground pipelines during the construction oftwin shield tunnel Ding et al [25] analyzed the law of soil dis-placement caused by shield tunnel construction of adjacentbuildings Liang et al [26] proposed a simplified analyticalmethod to predict the shield tunnel behaviors associated withadjacent excavation by introducing the Pasternak foundation

model with a modified subgrade modulus Asano et al [27]presented an observational excavation control method for amountain tunnel excavated adjacent to an existing tunnel inactive service Xu et al [28] obtained the stress expressionsof mutual influence of parallel tunnels from the point of viewof linear elasticity and proposed the concept of interferencecoefficient in the proximity construction impact zoning

Summarizing previous studies it is found that the currentresearch on the influence zone of tunnel adjacent construc-tion is rarely about the underwater tunnel Using the Japanesetunnel construction guidelines as examples all of them arecomprehensively evaluated on the basis of distance engi-neering geology and construction design When applied tounderwater tunnels it is insufficient due to the lack of consid-eration of water weakening and permeation to surroundingrock In addition most scholars use the MohrndashCoulombfailure criterion for the theoretical analysis Based on thedevelopment of constitutive models of rock mass in recentyears the HoekndashBrown failure criterion is considered as amore universal model The HoekndashBrown nonlinear theoryis extensively used in various kinds of problems due to itsrelatively accurate solutions In this study based on theHoek-Brown yield criterion considering the influence of waterseepage the elastoplastic analysis of the underwater tunnelconstruction is carried out and the method of zoning of theunderwater tunnel adjacent construction is further proposedCorresponding the influence zones with the risk levels in thecode then the appropriate control measures are selected onthe basis of the risk level to guide the site construction

2 Elastoplastic Analysis of Surrounding Rockunder Seepage Conditions

21 HoekndashBrown Failure Criterion and Basic AssumptionsBased on the Griffith brittle fracture theory the HoekndashBrownfailure criterion believed that the cause of rock failure isthe deformation and expansion of the existing cracks whichhas no significant relationship with the complete rock bodyyield strength It is assumed that the rock mass cracks areirregular and the whole rock is isotropic After years ofresearch and development the HoekndashBrown failure criterionhas been amended several times Finally the relationshipbetween rock parameters 119898 119904 120572 and GSI is established andits mathematical expression is as follows

1205901 = 1205903 + 120590119888 (119898119887 1205903120590119888 + 119904)120572 (1)

In the formula1205901 and1205903 are themaximumandminimumprincipal stresses when rock mass is destroyed (the compres-sive stress is positive) 120590119888 is the uniaxial compressive strengthof complete rock mass and m s and 120572 are the dimensionlessparameter which have the following equivalent expressions

119898119887 = 119898119894 sdot exp [(119866119878119868 minus 100)(28 minus 14119863) ] (2)

119904 = exp [(119866119878119868 minus 100)(9 minus 3119863) ] (3)

Mathematical Problems in Engineering 3

120572 = 12 +(119890minus11986611987811986815 minus 119890minus203)

6 (4)

In the formula D is the disturbance factor that reflects thetype of rock mass and GSI reflects the integrity of rock mass

Based on the revised HoekndashBrown failure criterion theelasticndashplastic stress state of underwater tunnel excavation isanalyzed and the calculation model is shown in Figure 1 Inthe model the tunnel section shape is circular the radius ofthe tunnel is 119886 the inner water head is ℎ119886 the surroundingrock plastic zone radius is119877119901 thewater head at the edge of theplastic zone is ℎ119901 the normal stress at the interface betweenthe elastic zone and the plastic zone is 119875119901 and the elastic zoneradius is 119877119890 the water head far enough is ℎ0 the originalrock stress of the surrounding rock is 1198750 and the liningsupport force is 119875119886 In order to simplify the calculationmodeland the solution process the following basic assumptionsare made during the solution of the circular tunnel (1)assuming that the surrounding rocks around the tunnel arehomogeneous rocks and ignoring the selfndashweight of thecalculation unit the lateral pressure coefficient is 10 (2)with the same permeability coefficient of rocks the seepagedirection is radial to form a stable seepage field (3) thetunnel lining support force is evenly distributed along theradial direction (4) the length of the tunnel is long enoughto handle the problem as axially symmetric plane strainsduring calculation (5) finally the elastoplastic analysis of thesurrounding rock follows the HoekndashBrown failure criterion

22 Seepage Field Status Calculation According to Darcyrsquoslaw and the continuity equation of seepage flow in the under-water tunnel the seepage continuous equilibrium differentialequation (5) can be obtained Equations (6) and (7) are theseepage flow boundary conditions which are expressed asfollows

12059721198671205971199032 + 1119903 120597119867120597119903 = 0 (5)

119867(119903)119903=119886 = ℎ119886 (6)

119867(119903)119903=119877119890 = ℎ0 (7)Combinedwith above equations thewater headH (r) can

be obtained

119867(119903) = 1ln (119877119890119886) (ℎ0 ln

119903119886 + ℎ119886 ln 119877119890119903 ) (8)

23 ElasticndashPlastic Zone Stress State Calculation When thestress state of the elasticndashplastic zone of the surrounding rockis calculated the seepage water pressure acts on the unit inthe form of volume force and the expression is as follows

119891119903 = minus120574119908 119889 (120585119867)119889119903 = 120574119908120585 (ℎ119886 minus ℎ0)119903 ln 119896 (9)

Considering the effect of seepage volume force accordingto elastoplastic calculation principle the balance differentialequation of elastic zone unit is expressed as follows

119889120590119903119889119903 + 120590119903 minus 120590120579119903 + 120574119908120585 (ℎ119886 minus ℎ0)119903 ln 119896 = 0 (10)

Plasticzone

Elastic zone

P0

P0

Rp

Pa

Re

a P0

P0

Figure 1 Calculation model of surrounding rock

In the formula 120590119903 is radial stress 120590120579 is tangential stress(tensile stress is positive and compressive stress is negative)120574119908 is the weight of water 120585 is the equivalent pore waterpressure coefficient and 119896 = 119877119890119886

After the unit is deformed according to thedisplacementndashstrain geometric equation (11) and thephysical stressndashstrain physical equation (12) then combinedwith the equilibrium differential equation (13) can beobtained

120576120579 = 119906119903 120576119903 = 119889119906119889119903 120574119903120579 = 0

(11)

120590119903 = (1 minus 120583) 119864(1 + 120583) (1 minus 2120583) (120576119903 +

1205831 + 120583120576120579)

120590120579 = (1 minus 120583) 119864(1 + 120583) (1 minus 2120583) (120576120579 +

1205831 + 120583120576119903) (12)

119906 = 1198623119903 + 1198624119903 + (1 + 120583) (1 minus 2120583)2 (1 minus 120583) 119864

times 120585120574119908 (ℎ0 minus ℎ119886)ln 119896 119903 ln 119903

(13)

After introducing the elastic boundary condition equa-tion (14) the expression of stress state in the elastic zone ofsurrounding rock considering the seepage condition can besolved as (15) and (16)


120590119903 100381610038161003816100381610038161003816119903=119877119901 = 119875119901120590119903 10038161003816100381610038161003816119903=119877120576 = 1198750

(14)

120590119903 = 1198750 + 120585120574119908 (ℎ0 minus ℎ119886) ln (119903119877119890)2 (1 minus 120583) ln (1119896) + 11987711990121198771199012 minus 1198771198902times (11987711989021199032 minus 1)

sdot [1198750 minus 119875119901 + 120585120574119908 (ℎ0 minus ℎ119886) ln (119877119901119877119890)2 (1 minus 120583) ln (1119896) ]

(15)

120590120579 = 1198750 + 120585120574119908 (ℎ0 minus ℎ119886) [ln (119903119877119890) + 2120583 minus 1]2 (1 minus 120583) ln (1119896)minus 11987711990121198771199012 minus 1198771198902 times (

11987711989021199032 + 1)

times [1198750 minus 119875119901 + 120585120574119908 (ℎ0 minus ℎ119886) ln (119877119901119877119890)2 (1 minus 120583) ln (1119896) ]

(16)

When the stress state of the plastic zone is calculated thesurrounding rock follows the HoekndashBrown failure criterionin the plastic zone According to the force analysis when120582 = 1 it can be known the tangential pressure 120590120579 isthe maximum principal stress 1205901 and the radial stress 120590r isthe minimum principal stress 1205903 the HoekndashBrown failurecriterion is expressed as follows

120590120579 = 120590119903 + 120590119888 (119898119887 120590119903120590119888 + 119904)120572 (17)

The equilibrium equation of the unit can be changed into(18) as follows

119889120590119903119889119903 minus 120590119888 (119898119887 (120590119903120590119888) + 119904)120572119903 + 120574119908120585 (ℎ0 minus ℎ119886)119903 ln 119896 = 0 (18)

After integrating (18) (19) and (20) can be obtainedAccording to (20) the amount of change of the radialstress along the radial direction in the plastic zone can bedetermined Furthermore according to (17) the amount ofchange of the tangential stress along the radial direction inthe plastic zone can be determined

int120590119903119875119886

119889120590119903120590119888 (119898119887 (120590119903120590119888) + 119904)120572 minus 120574119908120585 (ℎ0 minus ℎ119886) ln 119896 = int119903119886

119889119903119903= ln 119903119886

(19)

119903 = 119886times exp[int120590119903

119875119886

119889120590119903120590119888 (119898119887 (120590119903120590119888) + 119904)120572 minus 120574119908120585 (ℎ0 minus ℎ119886) ln 119896] (20)

24 Calculation of the Radius of Loose ZonendashBearing ZoneAccording to the definition of the ldquoloose areardquo it is assumed

that the tangential stress on the boundary of the loose area isthe original rock stress that is120590120579 = 120590119901 then it can be obtainedaccording to the Hoek-Brown failure criterion

120590120579 = 120590119897 + 120590119888 (119898119887 120590119897120590119888 + 119904)120572 = 1198750 (21)

Substituting (21) into (20) the radius of the loose zone canbe obtained as follows

119877119871 = 119886 sdot exp[int120590119897119875119886

1198891205901199031198750 minus 120590119903 minus 120574119908120585 (ℎ0 minus ℎ119886) ln 119896]= 119886 [1198750 minus 119875119886 minus 120574119908120585 (ℎ0 minus ℎ119886) ln 119896][1198750 minus 120590119897 minus 120574119908120585 (ℎ0 minus ℎ119886) ln 119896]

(22)

It can be seen from (22) that the mechanical parametersof rock mass groundwater pressure and seepage effect havea great influence on the radius of the loose zone Meanwhilethe larger the section size of the excavation tunnel the largerthe radius whereas the larger the tunnel support force 119875119886 thesmaller the radius

The radius of the bearing zone can be determined by thefollowing

int1198771198870119877119901

(120590120579119890 minus 1198750) 119889119903 = 12 int119877119890

119877119901

(120590120579119890 minus 1198750) 119889119903 (23)

By substituting (12) into (23) the radius of the bearingzone 119877b0 can be obtained

int1198771198870119877119901

[120585120574119908 (ℎ0 minus ℎ119886) [ln (119903119877119890) + 2120583 minus 1]2 (1 minus 120583) ln (1119896)+ 119877119901 21198771199012 minus 1198771198902 times (

11987711989021199032 + 1)

times [1198750 minus 119875119901 + 120585120574119908 (ℎ0 minus ℎ119886) ln (119877119901119877119890)2 (1 minus 120583) ln (1119896) ]] = 12sdot int119877119890119877119901

[120585120574119908 (ℎ0 minus ℎ119886) [ln (119903119877119890) + 2120583 minus 1]2 (1 minus 120583) ln (1119896)+ 11987711990121198771199012 minus 1198771198902 times (

11987711989021199032 + 1)

times [1198750 minus 119875119901 + 120585120574119908 (ℎ0 minus ℎ119886) ln (119877119901119877119890)2 (1 minus 120583) ln (1119896) ]]

(24)

3 Underwater Tunnel Adjacent ConstructionInfluence Zones Division

After the excavation of the underwater tunnel the initialstress equilibrium state of the surrounding rock is damagedand the stress is redistributed The rock stress around thetunnel exceeds the yield stress of the rock mass and the rock


becomes damaged or enters the plastic state Subsequentlythe stress of the plastic zone around the tunnel is partly trans-ferred to the deep rock mass due to the stress redistributionwhile the other part is relieved and eliminated due to thedeformation As the distance from the cave wall increasestheminimumradial principal stress increases and the bearingcapacity of the rock mass also increases which makes thestress state of the surrounding rock transition from plasticstate to elastic state in space

Compared with the initial state of stress the plastic zoneof surrounding rock can be divided into the bearing zoneand the loose zone after excavation The area in the deepplastic zone where the stress is higher than the initial stressand the area with the higher stress in the elastic area ofthe surrounding rock are combined as the ldquobearing zonerdquowhile the area whose stress is lower than the initial stressis the ldquoloose zonerdquo In the loose zone the stress and crackpropagation of the surrounding rock increase and the plasticslip is obvious When the surrounding rock reaches theplastic state all mechanical parameters are deteriorated Atthe same time the ldquoweakrdquo surrounding rock structure isfurther weakened by the action of groundwater throughpore hydrostatic pressure and hydrodynamic pressure whichmakes it easier to damage

According to the above analysis of the stress state ofthe surrounding rock after the underwater tunnel excavationand the stress graph of the surrounding rock the influencezone of the adjacent construction is divided The loose andbearing zones are considered to be the strong influence zoneIn the elastic zone under the elastic stress state the rangeof tangential stress at the hole edge greater than or equal to101 times of the initial stress is defined as the elastic stressconcentration zone Therefore the stress concentration zonein the elastic zone can be regarded as the weak influence zoneand the outer zone is an initial stress zone The influencezones division is shown in Figure 2

Based on theHoek-Brown failure criterion the loose zonecan be divided into three regions the strong influence weakinfluence and no influence zones and the strong influencezone can be divided into extensively strong influence stronginfluence and fairly strong influence zones

4 Engineering Example

The research on the influence zone division of the adjacentconstruction has a strong guiding role in the design andconstruction of underwater tunnels For example whenthe adjacent construction is in a strong influence zonereinforcement and support are required When it is in a weakinfluence zone monitoring measures are needed When it isin a no influence zone nomeasures are needed Figure 3 is anexample of underwater shield tunnel engineering

The underwater tunnel adopts Φ6250 earth pressurebalance shield machine construction Under the river theleft tunnel is parallel to the existing tunnel main line theminimum spacing between the outer contour of the tunneland the outer contour of the existing tunnel is 14700mThenbelow the river bank new tunnel underpasses the existingtunnel the vertical distance from the outer contour of the new

1 2 3 4

P

r

Figure 2 Elasticndashplastic stress status of the surrounding rock inunderwater tunnel In the figure 1 and 2 are the plastic and 3 and4 are the elastic zones 1 is the loose zone 2 and 3 are the bearingzones and 4 is the elastic stress concentration zone

A

B

147m

Existing tunnel

New tunnel

Figure 3 Location of the engineering example

tunnel to the main floor of the existing tunnel is 5442mTheriverbed strata are mainly highly weathered conglomerateand moderately weathered conglomerate exists locally Twotypical sections are selected for calculation and analysisAccording to geological data the water depth of the river insection A is 6m the depth of the shield tunnel is 10906mand the whole tunnel is in strong weathered conglomerateThe water depth of river in section B is 1m the depth ofthe shield tunnel is 2673m and the tunnel is also in strongweathered conglomerate

The relevant parameters at section A are as follows thetunnel radius is a = 314m the inner water head is ha = 0mthe water head far enough is h0 = 20m the original rockstress of surrounding rock is P0 = 04MPa the equivalentporewater pressure coefficient is 120585= 10 the surrounding rockelastic modulus is E = 45MPa Poissonrsquos ratio is 120583 = 03 thecohesion is c = 50 kPa and the internal friction angle is 120593 =37∘

By substituting r = 119877119901 in Equation (19) the radial stressPp of the surrounding rock at the elasticndashplastic zone can beobtained Then the plastic zone radius Re can be obtainedCombined with the relevant parameters of surrounding rockand tunnel the radius of the plastic zone after the excavationof tunnel is 576m


R953

R458 Existingtunnel

R1844

R576

Extremely strong impact zoneStrong impact zoneFairly Strong impact zoneWeak impact zoneNo impact zone

Figure 4 Influence zones of section A

The radii of the loose zone and the bearing zone arefurther solved according to (22) When substituting thesurrounding rock and tunnel parameters into the equationthe following can be obtained the loose and bearing zonesradii are 458m and 953m Therefore the range of exten-sively strong influence zone is 3ndash458m the range of stronginfluence zone is 458ndash576m and the range of fairly stronginfluence zone is 576ndash953m After solving the radius ofthe loose and bearing zones according to (15) and (16)then combining the calculation result of the plastic zone thefollowing can be obtained the radius of stress concentrationin the elastic zone is 1844m so the radius of the weakinfluence zone is 1844m The influence zones of section Aare shown in Figure 4

The relevant parameters at section B are as follows thetunnel radius is a = 314m the inner water head is ha = 0mthe water head far enough is h0 = 10m the original rock stressof surrounding rock is P0 = 05MPa and the equivalent porewater pressure coefficient is 120585 = 10 and the surrounding rockelastic modulus is E = 50MPa the Poissonrsquos ratio is 120583 = 02the cohesion is c = 55 kPa and the internal friction angle is 120593= 40∘

Based on the process of calculating the radius of theinfluence zones in section A the radius of the influence zonesin section B can be calculated as follows

It can be obtained from (19) that the radius of the tunnelexcavation plasticity influence zone is 617m then the radiusof the loose zone is 472m and the radius of the bearingzone is 828m Therefore the range of extensively stronginfluence zone is 3ndash472m the range of strong influence zoneis 472ndash617m and the range of fairly strong influence zone is617ndash828m Similarly the radius of the stress concentrationzone in the elastic zone is 1522m so the radius of the weakinfluence zone is 1522mThe influence zones of section B areshown in Figure 5

5 Adjacent Construction Influence Zones andRisk Classification

On the basis of the adjacent construction influence zone divi-sion different influence zones of the adjacent constructionare associated with different risk levels in the risk assessmentso that the risk level can be determined according to differentinfluence zones during construction Then the correspond-ing measures can be taken Different countermeasures areadopted for the adjacent construction with different risklevels which has guiding significance for the actual project

Referring to (GB50652ndash2011 underground rail transiturban construction risk management practices) [29] (GB T 50839ndash2013 urban rail transit safety control technicalspecifications) [30] and (CJJ T 202ndash2013 urban railtransit structural safety protection technical specifications)[31] the influence zones obtained above and risk levels arecorresponded Different risk levels should be taken differentrisk disposal guidelines and control plans as shown inTable 1

6 Control Measures

For the adjacent construction three aspects can be controlledone is to reinforce the existing structure the other is tostrengthen the new structure and the third is to takemeasures against the soil between the existing and the newstructuresTherefore the followingmeasures can be taken forthe adjacent construction(1) Measures to be taken for the existing tunnels orprojects the types of countermeasures include basic mea-sures strengthening measures and repairing measures Thebasic measures include backfilling grouting and preventtunnel lining off the block Strengthening measures includethe use of arches anchorage and crossbar to strengthen


R1522

R617R828

R472

Existingtunnel


Figure 5 Influence zones of section B

tunnel linings Repairing measures include stripping of float-ing blocks that may fall off cleaning the surface of thetunnel lining repairing drainage ditch and preventing waterleakage(2)Measures to be taken for the new tunnels or projectswhen construction has to be conducted in a strong-influencezone in order to reduce the impact on the existing tunnel amore perfect construction scheme or new countermeasuresshould be developed The concrete measures include adjust-ing the driving parameters and changing the supportingstructure of lining(3) Measures to be taken for the surrounding rockbetween the existing and the new construction or projectswhen the adjacent construction has a bad influence theprotection of the existing tunnel and the measures taken tothe side of the new construction are insufficient measuresshould be taken to deal with the intermediate strata inorder to reduce or eliminate the impact Generally methodssuch as grouting method and freezing method are adoptedto strengthen and improve the stratum and methods ofisolating influencemay also be adopted such as undergroundcontinuous walls pipe sheds steel pipe piles and archprotection

Under normal circumstances the abovemeasures are notcompletely independently used and comprehensive appli-cation can achieve better control effect In addition con-struction monitoring is an important part of undergroundengineering Due to the high risk complexity and unpre-dictability of adjacent construction monitoring is even moresignificantMonitoring datamust be fed back in time to guidefollow-up construction

Based on the influence degree of the adjacent construc-tion the risk level is judged and then the actual situation ofthe site is combined to take corresponding measures For thegrade I risk level the existing structure the new structureand the surrounding rock between the existing structure andthe new structure should be taken reinforcement measuresFor the grade II risk level the new structure and thesurrounding rock between the existing structure and thenew structure should take reinforcement measures and themonitoring of existing structures is needed For the gradeIII risk level the surrounding rock between the existingstructure and the new structure should take reinforcementmeasures and the monitoring of the existing and the newstructures are needed For the grade IV risk level themonitoring of the existing and the new structures are neededso as to grasp the impact of construction in real time

7 Conclusions

In this paper based on the HoekndashBrown failure criterion thetheoretical analysis is conducted on the underwater tunneladjacent construction In consideration of seepage flow theinfluence zone of underwater tunnel adjacent construction isdivided then influence zones are matched with risk levels inthe code The following conclusions can be obtained(1)The elasticndashplastic stress state of the surrounding rockof underwater tunnel is different from that of ordinary tunnelThe seepage action can cause a certain degree of deteriorationto the surrounding rock which cannot be ignored(2) According to the proposed zoning method for theinfluence zone of underwater tunnel adjacent construction in


Table1Ad

jacent

constructio

ninflu

ence

zone

andris

kcla

ssificatio

n

No

Adjacent

constructio

ninflu

ence

zone

Risk

levelAc

cepted

guidelines

Disp

osalguidelines

Con

trolplans

1Ex

tensively

influ

ence

zone

LevelI

Unacceptable

Risk

controlm

easuresm

ustb

eimplem

entedto

redu

cethe

riskatleasttoalevelthatiseither

acceptableor

unwilling

Risk

warning

andem

ergencyrespon

seprograms

orprogram

amendm

entsor

adjustmentsshou

ldbe

prepared

2Strong

influ

ence

zone

LevelII

Unw

illingto

accept

Risk

managem

entsho

uldbe

implem

entedto

redu

ceris

kand

thec

osto

frisk

redu

ctionshou

ldno

tbeh

igherthanther

iskaft

erther

iskof

loss

Risk

preventio

nandmon

itorin

gshou

ldbe

implem

entedandris

kmanagem

entm

easures

shou

ldbe

form

ulated

3FairlyStrong

influ

ence

zone

LevelIII

Acceptable

Risk

managem

entsho

uldbe

implem

entedandris

kmanagem

entm

easuresc

anbe

taken

Thed

ailymanagem

entand

mon

itorin

gfre

quency

shou

ldbe

increased

4Weakinflu

ence

zone

LevelIV

Igno

rable

Canim

plem

entrisk

managem

ent

Exam

inationcanbe

cond

ucteddaily

5Noinflu

ence

zone

Non

eNo

Noneed

toconsider

ther

iskGeneralmanagem

entsho

uldbe

checked


this study the influence zone can be divided into extensivelystrong strong fairly strong weak and no-impact zonesDuring the construction measures will be taken on the basisof the different influence zone(3) The influence zones are matched with the risk levelsand different countermeasures are taken according to differ-ent risk levels which have guiding significance for the siteconstruction

Symbols

1205901 The maximum principal stress MPa1205903 The minimum principal stress MPa120590119888 The uniaxial compressive strength ofcomplete rock mass MPa

m The dimensionless parameterS The dimensionless parameter120572 The dimensionless parameterD The disturbance factor that reflects the

type of rock massGSI The integrity of rock mass119886 The radius of the tunnel mℎ119886 The inner water head m119877119901 The surrounding rock plastic zone radius

mℎ119901 The plastic zone radius head m119875119901 The elasticndashplastic contact interface at thenormal stress N119877119890 The elastic zone radius m119877119871 The loose zone radius mℎ0 The water head far enough m1198750 The original rock stress of the surroundingrock N119875119886 The lining support force N120590119903 The radial stress MPa120590120579 The tangential stress MPa120574119908 The unit weight of water120585 The equivalent pore water pressurecoefficient

Data Availability

The data used to support the findings of this study areavailable from the corresponding author upon request

Additional Points

Outlook Some issues remain to be addressed in future stud-ies In the latter study field test andmodel experimentswill becarried out to improve the calculationmethod of the adjacentconstruction influence zone division Further a constructionmanual to guide the adjacent-construction will be preparedand a complete set of adjacent-construction technology willbe formed to ensure the safety of construction

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this study

Acknowledgments

The study presented in this article is supported by theNational Science Foundation of China Research Grant no50908234

References

[1] Design Manual Tunnel Construction Maintenance Edition(Adjacent Construction) Japan Highway Public Corporation1998

[2] W G ChouThe study on mechanics principle and countermea-sure of approaching excavation in underground works [PhDDissertation] Southwest Jiao tong University Chengdu China2003

[3] J L Du In-Situ Experimental Research on Soil DisturbanceCharacteristics during The Shield Construction Process WhenLarge Shield Was Crossing Existing Subway Shanghai Jiao TongUniversity Shanghai China 2009

[4] C-L Li and L-C Miao ldquoDetermination of the range of shieldtunneling-induced soil disturbancerdquo Yantu LixueRock and SoilMechanics vol 37 no 3 pp 759ndash766 2016

[5] X Huang H Huang and D Zhang ldquoCentrifuge modellingof deep excavation over existing tunnelsrdquo Proceedings of theInstitution of Civil Engineers Geotechnical Engineering vol 167no 1 pp 3ndash18 2014

[6] Y F Xu J S Chen and D M Fu ldquoEffect of shield tunnelingon mechanical properties of soilsrdquo Chinese Journal of RockMechanics and Engineering vol 22 no 7 pp 1174ndash1179 2003(Chinese)

[7] C F Tao and Y Chen ldquoCalculation and analysis of plastic areaand ground settlement for shield tunnelrdquo Modern Transporta-tion Technology vol 6 no 5 pp 55ndash57 2009

[8] X Huang H F Schweiger and H Huang ldquoInfluence of deepexcavations on nearby existing tunnelsrdquo International Journalof Geomechanics vol 13 no 2 pp 170ndash180 2013

[9] M-N Wang X-J Zhang M-Z Gou and G-Y Cui ldquoMethodof three-dimensional simulation for shield tunneling processand study of adjacent partition of overlapped segmentrdquo YantuLixueRock and Soil Mechanics vol 33 no 1 pp 273ndash279 2012

[10] B Liu D Zhang and L Fang ldquoStructural response of existedmetro tunnels to adjacent large-section pipe jacking construc-tionrdquo Procedia Engineering vol 189 pp 11ndash17 2017

[11] V Avgerinos D M Potts and J R Standing ldquoNumericalinvestigation of the effects of tunnelling on existing tunnelsrdquoTunnelling in the Urban Environment vol 67 no 9 pp 808ndash8222018

[12] Z Zhang and M Huang ldquoGeotechnical influence on existingsubway tunnels induced bymultiline tunneling in Shanghai softsoilrdquo Computers amp Geosciences vol 56 pp 121ndash132 2014

[13] Z F Hu Z Q Yue J Zhou and L G Tham ldquoDesign andconstruction of a deep excavation in soft soils adjacent to theShanghai Metro tunnelsrdquo Canadian Geotechnical Journal vol40 no 5 pp 933ndash948 2003

[14] J S Sharma A M Hefny J Zhao and C W Chan ldquoEffectof large excavation on deformation of adjacent MRT tunnelsrdquoTunnelling and Underground Space Technology vol 16 no 2 pp93ndash98 2001

[15] M Fang and Z Liu ldquo3D numerical simulation of influence ofundercrossing shield construction on existing tunnelrdquo Journalof Railway Science and Engineering vol 8 no 1 pp 67ndash72 2011


[16] J X Wang X Z Yang and B Ruan ldquoNumerical simulation ofshield tunnel construction on the impact of neighboring pilesfoundationrdquo Journal of Railway Science and Engineering vol 11no 1 pp 73ndash78 2014

[17] R B Peck ldquoDeep excavation and tunneling in soft groundState of the Art Reportrdquo in Proceedings of the 7th InternationalConference on Soil Mechanics and Foundation Engineering vol7 pp 225ndash290 1969

[18] C Sagaseta ldquoAnalysis of undrained soil deformation due toground lossrdquo Geotechnique vol 37 no 3 pp 301ndash320 1987

[19] R C J Howland ldquoStresses in a plate containing an infinite rowof holesrdquo Proceedings of the Royal Society of London Series A -Mathematical and Physical Sciences vol 148 no 864 pp 471ndash491 1935

[20] CWWNg J Shi and YHong ldquoThree-dimensional centrifugemodelling of basement excavation effects on an existing tunnelin dry sandrdquo Canadian Geotechnical Journal vol 50 no 8 pp874ndash888 2013

[21] Y-B Zhao and Z-M Zhang ldquoAdditional stress of surroundingsoil caused by propelling of shield tunnelingrdquo Yantu GongchengXuebaoChinese Journal of Geotechnical Engineering vol 32 no9 pp 1386ndash1391 2010

[22] J-F Zhang J-J Chen J-H Wang and Y-F Zhu ldquoPredictionof tunnel displacement induced by adjacent excavation in softsoilrdquo Tunnelling and Underground Space Technology vol 36 pp24ndash33 2013

[23] B Nawel and M Salah ldquoNumerical modeling of two paralleltunnels interaction using three-dimensional finite elementsmethodrdquo Geomechanics and Engineering vol 9 no 6 pp 775ndash791 2015

[24] G Wei X Lin and R Jin ldquoSecurity discrimination of adjacentunderground pipelines during the construction of twin shieldtunnelsrdquo Rock and soil Mechanics vol 1 pp 181ndash190 2018

[25] Z Ding X-J Wei and G Wei ldquoPrediction methods ontunnel-excavation induced surface settlement around adjacentbuildingrdquoGeomechanics and Engineering vol 12 no 2 pp 185ndash195 2017

[26] R Liang W Wu F Yu G Jiang and J Liu ldquoSimplified methodfor evaluating shield tunnel deformation due to adjacent exca-vationrdquo Tunnelling and Underground Space Technology vol 71pp 94ndash105 2018

[27] T AsanoM Ishihara Y Kiyota H Kurosawa and S Ebisu ldquoAnobservational excavation controlmethod for adjacentmountaintunnelsrdquo Tunnelling and Underground Space Technology vol 18no 2-3 pp 291ndash301 2003

[28] R D Xu and L S Xu ldquoLinear elastic analysis of stress insurrounding rock of double tunnelsrdquo Geotechnical EngineeringTechnique vol 19 no 3 pp 127ndash129 2005

[29] GB 50652 ldquoCode for risk management of underground worksin urban rail transit Chinardquo 2011

[30] GBT 50839 ldquoTechnical code of urban rail transit engineeringsafety control Chinardquo 2013

[31] CJJT ldquoUrban rail transit structural safety protection technicalspecifications Chinardquo 2013

Hindawiwwwhindawicom Volume 2018

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International Journal of


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Journal of


Function SpacesAbstract and Applied AnalysisHindawiwwwhindawicom Volume 2018

International Journal of Mathematics and Mathematical Sciences


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Hindawiwwwhindawicom Volume 2018Volume 2018

Numerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisNumerical AnalysisAdvances inAdvances in Discrete Dynamics in

Nature and SocietyHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Dierential EquationsInternational Journal of

Volume 2018


Decision SciencesAdvances in


AnalysisInternational Journal of


Stochastic AnalysisInternational Journal of

Submit your manuscripts atwwwhindawicom


stress due to shield tunneling Tao et al [7] calculated thestress of infinite elastic plate by using elastic theory of planestrain in which the stress and the different stress of it onlycaused before metro tunnel excavation were piled up andthen derived ground settlement curve equation from thesolution of infinite elastic plate Huang et al [8] presenteda finite-element parametric study of tunnel behavior causedby nearby deep excavation and investigated the effects ofseveral parameters that may affect the tunnel response Wanget al [9] established a three-dimensional simulation methodthat can fully reflect the whole process of shield tunnelingto study the impact of the adjacent construction to the pilefoundation Liu et al [10] investigated the effects of pipejacking on existing underlying tunnels and analyzed thevertical displacement horizontal displacement and diameterconvergence of the tunnel based on the field observationsAvgerinos et al [11] developed a basic three-dimensional (3D)finite-element (FE) model and discussed changes in hoopforces bending moments and lining deformations of theexiting tunnel due to excavation of the new tunnel Zhanget al [12] presented the deformation analyses of existingsubway tunnels induced by an earth pressure balance (EPB)shield during the process of above-overlapped and down-overlapped crossing tunnels with oblique angles based onthe Shanghai Railway transportation project and in situmonitoring data Hu et al [13] discussed in detail the criteriaandmeasures for controlling the soil and tunnel deformationSharma et al [14] found that the stiffness of the tunnellining has significant influence on the displacement anddistortion of tunnels caused by an adjacent excavation Inworks [15 16] different numerical simulation methods werealso used to evaluate the influence zone of the adjacentconstruction In theoretical deduction the influence zoneof the adjacent construction was often simplified to theelastic mechanics analysis and calculation of double-holeor multihole tunnel excavation Classical solutions are asfollows Peck formation loss model [17] Sagaseta ldquomirrormethodrdquo [18] and Howland [19] infinite circular hole stressfunction Ng et al [20] designed and carried out two three-dimensional centrifuge tests in dry sand to investigate theeffects of a basement excavation on an existing tunnel locatedin two horizontal offsets in relation to the basement Zhao etal [21] determined the additional stress of shield tunneling onthe basis of Mindlin solution of elastic mechanics to evaluatethe influence range Zhang et al [22] used a viscoelastoplasticmodel (VEP model) to simulate the rheologic deformationof soil and studied the behavior of the tunnel underneathexcavation by the new method to discuss the influence ofdifferent factors including excavation area relative distanceand construction procedure Nawel et al [23] used FiniteElement Method to simulate numerically the interactioneffects caused by construction of two parallels tunnels Weiet al [24] presented a method for security discrimination ofadjacent underground pipelines during the construction oftwin shield tunnel Ding et al [25] analyzed the law of soil dis-placement caused by shield tunnel construction of adjacentbuildings Liang et al [26] proposed a simplified analyticalmethod to predict the shield tunnel behaviors associated withadjacent excavation by introducing the Pasternak foundation

model with a modified subgrade modulus Asano et al [27]presented an observational excavation control method for amountain tunnel excavated adjacent to an existing tunnel inactive service Xu et al [28] obtained the stress expressionsof mutual influence of parallel tunnels from the point of viewof linear elasticity and proposed the concept of interferencecoefficient in the proximity construction impact zoning

Summarizing previous studies it is found that the currentresearch on the influence zone of tunnel adjacent construc-tion is rarely about the underwater tunnel Using the Japanesetunnel construction guidelines as examples all of them arecomprehensively evaluated on the basis of distance engi-neering geology and construction design When applied tounderwater tunnels it is insufficient due to the lack of consid-eration of water weakening and permeation to surroundingrock In addition most scholars use the MohrndashCoulombfailure criterion for the theoretical analysis Based on thedevelopment of constitutive models of rock mass in recentyears the HoekndashBrown failure criterion is considered as amore universal model The HoekndashBrown nonlinear theoryis extensively used in various kinds of problems due to itsrelatively accurate solutions In this study based on theHoek-Brown yield criterion considering the influence of waterseepage the elastoplastic analysis of the underwater tunnelconstruction is carried out and the method of zoning of theunderwater tunnel adjacent construction is further proposedCorresponding the influence zones with the risk levels in thecode then the appropriate control measures are selected onthe basis of the risk level to guide the site construction

2 Elastoplastic Analysis of Surrounding Rockunder Seepage Conditions

21 HoekndashBrown Failure Criterion and Basic AssumptionsBased on the Griffith brittle fracture theory the HoekndashBrownfailure criterion believed that the cause of rock failure isthe deformation and expansion of the existing cracks whichhas no significant relationship with the complete rock bodyyield strength It is assumed that the rock mass cracks areirregular and the whole rock is isotropic After years ofresearch and development the HoekndashBrown failure criterionhas been amended several times Finally the relationshipbetween rock parameters 119898 119904 120572 and GSI is established andits mathematical expression is as follows

1205901 = 1205903 + 120590119888 (119898119887 1205903120590119888 + 119904)120572 (1)

In the formula1205901 and1205903 are themaximumandminimumprincipal stresses when rock mass is destroyed (the compres-sive stress is positive) 120590119888 is the uniaxial compressive strengthof complete rock mass and m s and 120572 are the dimensionlessparameter which have the following equivalent expressions

119898119887 = 119898119894 sdot exp [(119866119878119868 minus 100)(28 minus 14119863) ] (2)

119904 = exp [(119866119878119868 minus 100)(9 minus 3119863) ] (3)



6 (4)




12059721198671205971199032 + 1119903 120597119867120597119903 = 0 (5)

119867(119903)119903=119886 = ℎ119886 (6)


be obtained

119867(119903) = 1ln (119877119890119886) (ℎ0 ln

119903119886 + ℎ119886 ln 119877119890119903 ) (8)


119891119903 = minus120574119908 119889 (120585119867)119889119903 = 120574119908120585 (ℎ119886 minus ℎ0)119903 ln 119896 (9)


119889120590119903119889119903 + 120590119903 minus 120590120579119903 + 120574119908120585 (ℎ119886 minus ℎ0)119903 ln 119896 = 0 (10)

Plasticzone

Elastic zone

P0

P0

Rp

Pa

Re

a P0

P0




120576120579 = 119906119903 120576119903 = 119889119906119889119903 120574119903120579 = 0

(11)

120590119903 = (1 minus 120583) 119864(1 + 120583) (1 minus 2120583) (120576119903 +

1205831 + 120583120576120579)

120590120579 = (1 minus 120583) 119864(1 + 120583) (1 minus 2120583) (120576120579 +

1205831 + 120583120576119903) (12)

119906 = 1198623119903 + 1198624119903 + (1 + 120583) (1 minus 2120583)2 (1 minus 120583) 119864


(13)



120590119903 100381610038161003816100381610038161003816119903=119877119901 = 119875119901120590119903 10038161003816100381610038161003816119903=119877120576 = 1198750

(14)



(15)


11987711989021199032 + 1)


(16)


120590120579 = 120590119903 + 120590119888 (119898119887 120590119903120590119888 + 119904)120572 (17)


119889120590119903119889119903 minus 120590119888 (119898119887 (120590119903120590119888) + 119904)120572119903 + 120574119908120585 (ℎ0 minus ℎ119886)119903 ln 119896 = 0 (18)


int120590119903119875119886


119889119903119903= ln 119903119886

(19)

119903 = 119886times exp[int120590119903

119875119886

119889120590119903120590119888 (119898119887 (120590119903120590119888) + 119904)120572 minus 120574119908120585 (ℎ0 minus ℎ119886) ln 119896] (20)



120590120579 = 120590119897 + 120590119888 (119898119887 120590119897120590119888 + 119904)120572 = 1198750 (21)


119877119871 = 119886 sdot exp[int120590119897119875119886


(22)



int1198771198870119877119901

(120590120579119890 minus 1198750) 119889119903 = 12 int119877119890

119877119901

(120590120579119890 minus 1198750) 119889119903 (23)


int1198771198870119877119901


11987711989021199032 + 1)



11987711989021199032 + 1)


(24)











1 2 3 4

P

r


A

B

147m

Existing tunnel

New tunnel






R953

R458 Existingtunnel

R1844

R576










6 Control Measures



R1522

R617R828

R472

Existingtunnel






7 Conclusions



Table1Ad

jacent

constructio

ninflu

ence

zone

andris

kcla

ssificatio

n

No

Adjacent

constructio

ninflu

ence

zone

Risk

levelAc

cepted

guidelines

Disp

osalguidelines

Con

trolplans

1Ex

tensively

influ

ence

zone

LevelI

Unacceptable

Risk

controlm

easuresm

ustb

eimplem

entedto

redu

cethe


acceptableor

unwilling

Risk

warning

andem

ergencyrespon

seprograms

orprogram

amendm

entsor

adjustmentsshou

ldbe

prepared

2Strong

influ

ence

zone

LevelII

Unw

illingto

accept

Risk

managem

entsho

uldbe

implem

entedto

redu

ceris

kand

thec

osto

frisk

redu

ctionshou

ldno

tbeh

igherthanther

iskaft

erther

iskof

loss

Risk

preventio

nandmon

itorin

gshou

ldbe

implem

entedandris

kmanagem

entm

easures

shou

ldbe

form

ulated

3FairlyStrong

influ

ence

zone

LevelIII

Acceptable

Risk

managem

entsho

uldbe

implem

entedandris

kmanagem

entm

easuresc

anbe

taken

Thed

ailymanagem

entand

mon

itorin

gfre

quency

shou

ldbe

increased

4Weakinflu

ence

zone

LevelIV

Igno

rable

Canim

plem

entrisk

managem

ent

Exam

inationcanbe

cond

ucteddaily

5Noinflu

ence

zone

Non

eNo

Noneed

toconsider

ther

iskGeneralmanagem

entsho

uldbe

checked



Symbols





Data Availability


Additional Points




Acknowledgments


References








































Journal of












Journal of







Volume 2018






Volume 2018










6 (4)




12059721198671205971199032 + 1119903 120597119867120597119903 = 0 (5)

119867(119903)119903=119886 = ℎ119886 (6)


be obtained

119867(119903) = 1ln (119877119890119886) (ℎ0 ln

119903119886 + ℎ119886 ln 119877119890119903 ) (8)


119891119903 = minus120574119908 119889 (120585119867)119889119903 = 120574119908120585 (ℎ119886 minus ℎ0)119903 ln 119896 (9)


119889120590119903119889119903 + 120590119903 minus 120590120579119903 + 120574119908120585 (ℎ119886 minus ℎ0)119903 ln 119896 = 0 (10)

Plasticzone

Elastic zone

P0

P0

Rp

Pa

Re

a P0

P0




120576120579 = 119906119903 120576119903 = 119889119906119889119903 120574119903120579 = 0

(11)

120590119903 = (1 minus 120583) 119864(1 + 120583) (1 minus 2120583) (120576119903 +

1205831 + 120583120576120579)

120590120579 = (1 minus 120583) 119864(1 + 120583) (1 minus 2120583) (120576120579 +

1205831 + 120583120576119903) (12)

119906 = 1198623119903 + 1198624119903 + (1 + 120583) (1 minus 2120583)2 (1 minus 120583) 119864


(13)



120590119903 100381610038161003816100381610038161003816119903=119877119901 = 119875119901120590119903 10038161003816100381610038161003816119903=119877120576 = 1198750

(14)



(15)


11987711989021199032 + 1)


(16)


120590120579 = 120590119903 + 120590119888 (119898119887 120590119903120590119888 + 119904)120572 (17)


119889120590119903119889119903 minus 120590119888 (119898119887 (120590119903120590119888) + 119904)120572119903 + 120574119908120585 (ℎ0 minus ℎ119886)119903 ln 119896 = 0 (18)


int120590119903119875119886


119889119903119903= ln 119903119886

(19)

119903 = 119886times exp[int120590119903

119875119886

119889120590119903120590119888 (119898119887 (120590119903120590119888) + 119904)120572 minus 120574119908120585 (ℎ0 minus ℎ119886) ln 119896] (20)



120590120579 = 120590119897 + 120590119888 (119898119887 120590119897120590119888 + 119904)120572 = 1198750 (21)


119877119871 = 119886 sdot exp[int120590119897119875119886


(22)



int1198771198870119877119901

(120590120579119890 minus 1198750) 119889119903 = 12 int119877119890

119877119901

(120590120579119890 minus 1198750) 119889119903 (23)


int1198771198870119877119901


11987711989021199032 + 1)



11987711989021199032 + 1)


(24)











1 2 3 4

P

r


A

B

147m

Existing tunnel

New tunnel






R953

R458 Existingtunnel

R1844

R576










6 Control Measures



R1522

R617R828

R472

Existingtunnel






7 Conclusions



Table1Ad

jacent

constructio

ninflu

ence

zone

andris

kcla

ssificatio

n

No

Adjacent

constructio

ninflu

ence

zone

Risk

levelAc

cepted

guidelines

Disp

osalguidelines

Con

trolplans

1Ex

tensively

influ

ence

zone

LevelI

Unacceptable

Risk

controlm

easuresm

ustb

eimplem

entedto

redu

cethe


acceptableor

unwilling

Risk

warning

andem

ergencyrespon

seprograms

orprogram

amendm

entsor

adjustmentsshou

ldbe

prepared

2Strong

influ

ence

zone

LevelII

Unw

illingto

accept

Risk

managem

entsho

uldbe

implem

entedto

redu

ceris

kand

thec

osto

frisk

redu

ctionshou

ldno

tbeh

igherthanther

iskaft

erther

iskof

loss

Risk

preventio

nandmon

itorin

gshou

ldbe

implem

entedandris

kmanagem

entm

easures

shou

ldbe

form

ulated

3FairlyStrong

influ

ence

zone

LevelIII

Acceptable

Risk

managem

entsho

uldbe

implem

entedandris

kmanagem

entm

easuresc

anbe

taken

Thed

ailymanagem

entand

mon

itorin

gfre

quency

shou

ldbe

increased

4Weakinflu

ence

zone

LevelIV

Igno

rable

Canim

plem

entrisk

managem

ent

Exam

inationcanbe

cond

ucteddaily

5Noinflu

ence

zone

Non

eNo

Noneed

toconsider

ther

iskGeneralmanagem

entsho

uldbe

checked



Symbols





Data Availability


Additional Points




Acknowledgments


References








































Journal of












Journal of







Volume 2018






Volume 2018









120590119903 100381610038161003816100381610038161003816119903=119877119901 = 119875119901120590119903 10038161003816100381610038161003816119903=119877120576 = 1198750

(14)



(15)


11987711989021199032 + 1)


(16)


120590120579 = 120590119903 + 120590119888 (119898119887 120590119903120590119888 + 119904)120572 (17)


119889120590119903119889119903 minus 120590119888 (119898119887 (120590119903120590119888) + 119904)120572119903 + 120574119908120585 (ℎ0 minus ℎ119886)119903 ln 119896 = 0 (18)


int120590119903119875119886


119889119903119903= ln 119903119886

(19)

119903 = 119886times exp[int120590119903

119875119886

119889120590119903120590119888 (119898119887 (120590119903120590119888) + 119904)120572 minus 120574119908120585 (ℎ0 minus ℎ119886) ln 119896] (20)



120590120579 = 120590119897 + 120590119888 (119898119887 120590119897120590119888 + 119904)120572 = 1198750 (21)


119877119871 = 119886 sdot exp[int120590119897119875119886


(22)



int1198771198870119877119901

(120590120579119890 minus 1198750) 119889119903 = 12 int119877119890

119877119901

(120590120579119890 minus 1198750) 119889119903 (23)


int1198771198870119877119901


11987711989021199032 + 1)



11987711989021199032 + 1)


(24)











1 2 3 4

P

r


A

B

147m

Existing tunnel

New tunnel






R953

R458 Existingtunnel

R1844

R576










6 Control Measures



R1522

R617R828

R472

Existingtunnel






7 Conclusions



Table1Ad

jacent

constructio

ninflu

ence

zone

andris

kcla

ssificatio

n

No

Adjacent

constructio

ninflu

ence

zone

Risk

levelAc

cepted

guidelines

Disp

osalguidelines

Con

trolplans

1Ex

tensively

influ

ence

zone

LevelI

Unacceptable

Risk

controlm

easuresm

ustb

eimplem

entedto

redu

cethe


acceptableor

unwilling

Risk

warning

andem

ergencyrespon

seprograms

orprogram

amendm

entsor

adjustmentsshou

ldbe

prepared

2Strong

influ

ence

zone

LevelII

Unw

illingto

accept

Risk

managem

entsho

uldbe

implem

entedto

redu

ceris

kand

thec

osto

frisk

redu

ctionshou

ldno

tbeh

igherthanther

iskaft

erther

iskof

loss

Risk

preventio

nandmon

itorin

gshou

ldbe

implem

entedandris

kmanagem

entm

easures

shou

ldbe

form

ulated

3FairlyStrong

influ

ence

zone

LevelIII

Acceptable

Risk

managem

entsho

uldbe

implem

entedandris

kmanagem

entm

easuresc

anbe

taken

Thed

ailymanagem

entand

mon

itorin

gfre

quency

shou

ldbe

increased

4Weakinflu

ence

zone

LevelIV

Igno

rable

Canim

plem

entrisk

managem

ent

Exam

inationcanbe

cond

ucteddaily

5Noinflu

ence

zone

Non

eNo

Noneed

toconsider

ther

iskGeneralmanagem

entsho

uldbe

checked



Symbols





Data Availability


Additional Points




Acknowledgments


References








































Journal of












Journal of







Volume 2018






Volume 2018
















1 2 3 4

P

r


A

B

147m

Existing tunnel

New tunnel






R953

R458 Existingtunnel

R1844

R576










6 Control Measures



R1522

R617R828

R472

Existingtunnel






7 Conclusions



Table1Ad

jacent

constructio

ninflu

ence

zone

andris

kcla

ssificatio

n

No

Adjacent

constructio

ninflu

ence

zone

Risk

levelAc

cepted

guidelines

Disp

osalguidelines

Con

trolplans

1Ex

tensively

influ

ence

zone

LevelI

Unacceptable

Risk

controlm

easuresm

ustb

eimplem

entedto

redu

cethe


acceptableor

unwilling

Risk

warning

andem

ergencyrespon

seprograms

orprogram

amendm

entsor

adjustmentsshou

ldbe

prepared

2Strong

influ

ence

zone

LevelII

Unw

illingto

accept

Risk

managem

entsho

uldbe

implem

entedto

redu

ceris

kand

thec

osto

frisk

redu

ctionshou

ldno

tbeh

igherthanther

iskaft

erther

iskof

loss

Risk

preventio

nandmon

itorin

gshou

ldbe

implem

entedandris

kmanagem

entm

easures

shou

ldbe

form

ulated

3FairlyStrong

influ

ence

zone

LevelIII

Acceptable

Risk

managem

entsho

uldbe

implem

entedandris

kmanagem

entm

easuresc

anbe

taken

Thed

ailymanagem

entand

mon

itorin

gfre

quency

shou

ldbe

increased

4Weakinflu

ence

zone

LevelIV

Igno

rable

Canim

plem

entrisk

managem

ent

Exam

inationcanbe

cond

ucteddaily

5Noinflu

ence

zone

Non

eNo

Noneed

toconsider

ther

iskGeneralmanagem

entsho

uldbe

checked



Symbols





Data Availability


Additional Points




Acknowledgments


References








































Journal of












Journal of







Volume 2018






Volume 2018









R953

R458 Existingtunnel

R1844

R576










6 Control Measures



R1522

R617R828

R472

Existingtunnel






7 Conclusions



Table1Ad

jacent

constructio

ninflu

ence

zone

andris

kcla

ssificatio

n

No

Adjacent

constructio

ninflu

ence

zone

Risk

levelAc

cepted

guidelines

Disp

osalguidelines

Con

trolplans

1Ex

tensively

influ

ence

zone

LevelI

Unacceptable

Risk

controlm

easuresm

ustb

eimplem

entedto

redu

cethe


acceptableor

unwilling

Risk

warning

andem

ergencyrespon

seprograms

orprogram

amendm

entsor

adjustmentsshou

ldbe

prepared

2Strong

influ

ence

zone

LevelII

Unw

illingto

accept

Risk

managem

entsho

uldbe

implem

entedto

redu

ceris

kand

thec

osto

frisk

redu

ctionshou

ldno

tbeh

igherthanther

iskaft

erther

iskof

loss

Risk

preventio

nandmon

itorin

gshou

ldbe

implem

entedandris

kmanagem

entm

easures

shou

ldbe

form

ulated

3FairlyStrong

influ

ence

zone

LevelIII

Acceptable

Risk

managem

entsho

uldbe

implem

entedandris

kmanagem

entm

easuresc

anbe

taken

Thed

ailymanagem

entand

mon

itorin

gfre

quency

shou

ldbe

increased

4Weakinflu

ence

zone

LevelIV

Igno

rable

Canim

plem

entrisk

managem

ent

Exam

inationcanbe

cond

ucteddaily

5Noinflu

ence

zone

Non

eNo

Noneed

toconsider

ther

iskGeneralmanagem

entsho

uldbe

checked



Symbols





Data Availability


Additional Points




Acknowledgments


References








































Journal of












Journal of







Volume 2018






Volume 2018









R1522

R617R828

R472

Existingtunnel






7 Conclusions



Table1Ad

jacent

constructio

ninflu

ence

zone

andris

kcla

ssificatio

n

No

Adjacent

constructio

ninflu

ence

zone

Risk

levelAc

cepted

guidelines

Disp

osalguidelines

Con

trolplans

1Ex

tensively

influ

ence

zone

LevelI

Unacceptable

Risk

controlm

easuresm

ustb

eimplem

entedto

redu

cethe


acceptableor

unwilling

Risk

warning

andem

ergencyrespon

seprograms

orprogram

amendm

entsor

adjustmentsshou

ldbe

prepared

2Strong

influ

ence

zone

LevelII

Unw

illingto

accept

Risk

managem

entsho

uldbe

implem

entedto

redu

ceris

kand

thec

osto

frisk

redu

ctionshou

ldno

tbeh

igherthanther

iskaft

erther

iskof

loss

Risk

preventio

nandmon

itorin

gshou

ldbe

implem

entedandris

kmanagem

entm

easures

shou

ldbe

form

ulated

3FairlyStrong

influ

ence

zone

LevelIII

Acceptable

Risk

managem

entsho

uldbe

implem

entedandris

kmanagem

entm

easuresc

anbe

taken

Thed

ailymanagem

entand

mon

itorin

gfre

quency

shou

ldbe

increased

4Weakinflu

ence

zone

LevelIV

Igno

rable

Canim

plem

entrisk

managem

ent

Exam

inationcanbe

cond

ucteddaily

5Noinflu

ence

zone

Non

eNo

Noneed

toconsider

ther

iskGeneralmanagem

entsho

uldbe

checked



Symbols





Data Availability


Additional Points




Acknowledgments


References








































Journal of












Journal of







Volume 2018






Volume 2018









Table1Ad

jacent

constructio

ninflu

ence

zone

andris

kcla

ssificatio

n

No

Adjacent

constructio

ninflu

ence

zone

Risk

levelAc

cepted

guidelines

Disp

osalguidelines

Con

trolplans

1Ex

tensively

influ

ence

zone

LevelI

Unacceptable

Risk

controlm

easuresm

ustb

eimplem

entedto

redu

cethe


acceptableor

unwilling

Risk

warning

andem

ergencyrespon

seprograms

orprogram

amendm

entsor

adjustmentsshou

ldbe

prepared

2Strong

influ

ence

zone

LevelII

Unw

illingto

accept

Risk

managem

entsho

uldbe

implem

entedto

redu

ceris

kand

thec

osto

frisk

redu

ctionshou

ldno

tbeh

igherthanther

iskaft

erther

iskof

loss

Risk

preventio

nandmon

itorin

gshou

ldbe

implem

entedandris

kmanagem

entm

easures

shou

ldbe

form

ulated

3FairlyStrong

influ

ence

zone

LevelIII

Acceptable

Risk

managem

entsho

uldbe

implem

entedandris

kmanagem

entm

easuresc

anbe

taken

Thed

ailymanagem

entand

mon

itorin

gfre

quency

shou

ldbe

increased

4Weakinflu

ence

zone

LevelIV

Igno

rable

Canim

plem

entrisk

managem

ent

Exam

inationcanbe

cond

ucteddaily

5Noinflu

ence

zone

Non

eNo

Noneed

toconsider

ther

iskGeneralmanagem

entsho

uldbe

checked



Symbols





Data Availability


Additional Points




Acknowledgments


References








































Journal of












Journal of







Volume 2018






Volume 2018










Symbols





Data Availability


Additional Points




Acknowledgments


References








































Journal of












Journal of







Volume 2018






Volume 2018
































Journal of












Journal of







Volume 2018






Volume 2018















Journal of












Journal of







Volume 2018






Volume 2018








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