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Matriks GALIAN DALAM DeepExcavation

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BIDANG

CODE LUAR NEGERI STANDAR INDONESIA

EUROCODE 7Geotechnical designPart 1: General rules

IBC 2012CHAPTER 18

SOILS AND FOUNDATIONS

PERATURAN KEPALA DINAS P2B PROV.DKI-JAKARTANO. 50 TAHUN 2007

(PERATURAN GUBERNUR DKI-JAKARTA THN 2009)

GALIAN DALAM

KlasifikasiAcuan

Code Code Guidelines/Peraturan/Pedoman

Aplikasi Perencanaan geoteknikPedoman Perencanaan Struktur dan Geoteknik

Bangunan

General Design Section 11 Overall stability

11.1 General(1) Principles (P) The provisions in this Section shall apply to the

overall stability of and movements in the ground, whether natural orfill, around foundations, retaining structures, natural slopes,embankments orexcavations.

(2) Account should be taken of overall stability clauses, related tospecific structures, in Sections 6 to 10 and 12.

11.2 Limit states(1)P All possible limit states for the particular ground shall be

considered in order to fulfil the fundamental requirements ofstability, limited deformations, durability and limitations inmovements of nearby structures or services.

(2) Some possible limit states are listed below: loss of overall stability of the ground and associated structures; excessive movements in the ground due to shear deformations,

settlement, vibration or heave; damage or loss of serviceability in neighbouring structures, roads

or services due to movements in the ground.

11.3 Actions and design situations(1) The list in 2.4.2(4) should be taken into account when selecting the

actions for calculation of limit states.(2)P The effects of the following circumstances shall be taken into

account, as appropriate:

construction processes;

new slopes or structures on or near the particular site;

previous or continuing ground movements from differentsources;

vibrations; climatic variations, including temperature change (freezing and

thawing), drought and heavy rain; vegetation or its removal;

human or animal activities;

variations in water content or pore-water pressure; wave action.

(3)P In ultimate limit states, design free water and ground-water levels,

or their combination, shall be selected from available hydrologicaldata and in situ observations to give the most unfavourableconditions that could occur in the design situation being considered.The possibility of failure of drains, filters or seals shall beconsidered.

(4) The possibility of emptying a canal or water reservoir formaintenance, or due to dam failure, should also be considered. Forserviceability limit states, less severe, more typical water level orpore-water pressure may be used.

(5) For slopes along waterfronts, the most unfavourable hydraulicconditions are normally steady seepage for the highest possibleground-water level and rapid draw-down of the free water level.

SECTION 1801GENERAL

1801.1 Scope. The provisions of this chapter shall apply to building andfoundation systems.1801.2 Design basis. Allowable bearing pressures, allowable stressesand design formulas provided in this chapter shall be used with theallowable stress design load combinations specified in Section 1605.3.The quality and design of materials used structurally in excavations andfoundations shall comply with the requirements specified in Chapters16,19,21,22 and 23 of this code. Excavations andfillsshallalso complywith Chapter 33.

1803.5.7 Excavation near foundations. Where excavation willremoveLateral support from any foundation, an investigation shallbe conductedTo assess the pot ent ia l consequences and address mitigat ionmeasures.

SECTION 1804EXCAVATION, GRADING AND FILL

1804.1 Excavation near foundations. Excavation for any purpose

shall not remove lateral support from any foundation without firstunderpinning or protecting the foundation against settlement or lateraltranslation.1804.2 Placement of backfill. The excavation outside the foundationshall be backfilled with soil that is free of organic material, constructiondebris, cobbles and boulders or with a controlled low-strength material(CLSM). The backfill shall be placed in lifts and compacted in a mannerthat does not damage the foundation or the waterproofing ordampproofing material.

CHAPTER 33SAFEGUARDS DURING CONSTRUCTION

SECTION 3304SITE WORK

3304.1 Excavation and fill. Excavation and fill for buildings andstructures shall be constructed or protected so as not to endanger life orproperty. Stumps and roots shall be removed from the soil to a depth ofnot less than 12 inches (305 mm) below the surface of the ground in thearea to be occupied by the building. Wood forms which have been usedin placing concrete, if within the ground or between foundation sills andthe ground, shall be removed before a building is occupied or used forany purpose. Before completion, loose or casual wood shall beremoved from direct contact with the ground under the building.

3304.1.1 Slope limits. Slopes for permanent fill shall be notsteeper than one unit vertical in two units horizontal (50-percent

Pasal 12 Perencanaan Galian, Stabilitas Lereng

(1) Perencanaan galian besmen dalam, harus dianalisis secara terincimengenai keamanan galiannya apabila dijumpai salah satu ataulebih kondisi sebagai berikut :a. Terdapat bangunan di sekitar zona tekanan aktif tanahb.Kondisi tanah adalah lempung lunak dan/atau loose uncemented

sandc.Kondisi pelaksanaan pembangunan yang menggunakan open-cut

dan/atau ground-anchored walld. Bila dilakukan penurunan muka air tanah lebih dari 3.00 m

(2) Untuk analisa perhitungan keamanan galian, tes tanah harusdilakukan dengan memperhatikan hal-hal sebagai berikut :a.Mencakup Tes triaksial CU (Consolidated Undrained) dengan

pengukuran tekanan air pori, sehingga didapatkan parameter kuatgeser kondisi tegangan total dan tegangan efektif.

b.Test konsolidasi harus dilakukan dengan memberikan bebanminimum sebesar 2 (dua) kali beban maksimum yang akan

bekerja dan denganm engakomodasi peninjauan heave.c.Bagian/daerah pengambilan contoh tanah mencakup kedalaman

1.50 kali lebar terkecil tapak besmen.d.Apabila pengambilan contoh tanah tak terganggu tidak

memungkinkan, maka dapat dilakukan test lapangan yang sesuai

(3) Angka keamanan kemantapan lereng untuk analisis stabilitas galiantanah, ditentukan sesuai tabel 1.

(4) Analisis struktur dinding penahan tanah dengan anggapan keadaanekses tekanan air pori terdrainase (drained) atau keadaan terburukyang mungkin timbul harus meliputi:a. Penjelasan sistem yang digunakanb. Pemodelan dari sistemc. Pembebanan (termasuk yang berhubungan dengan tahapan

galian tanah)d. Deformasie. Kehandalan strukturnyaDengan FK untuk struktur dinding penahan tanah sementara diambilminimal 1.25 (untuk kondisi terburuk) dan untuk kondisi permanensebesar = 2.0

(5) Untuk sistem galian yang menggunakan dinding penahan seperti


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(6)P In deriving design distributions of pore-water pressure, accountshall be taken of the possible range of permeability anisotropy andvariability of the ground.

11.4 Design and construction considerations(1)P The overall stability of a site and movements of natural or made

ground shall be checked taking into account comparableexperience, according to 1.5.2.2.

(2)P The overall stability and movement of ground supporting existing

buildings, new structures, slopes or excavations shall beconsidered.

(3) In cases where the stability of the ground cannot be clearly verifiedprior to design, additional investigations, monitoring and analysisshould be specified according to the provisions of 11.7.

(4) Typical structures for which an analysis of overall stability should beperformed are: ground retaining structures; excavations, slopes or embankments; foundations on sloping ground, natural slopes or embankments;foundations near an excavation, cut or buried structures, or

shore.

NOTE Stability problems or creep movements occur primarily incohesive soils with a sloping ground surface. However, instabilitycan also occur in non-cohesive soils and fissured rocks in slopeswhere the inclination, which may be determined by erosion, is closeto the angle of shearing resistance. Increased movements are often

observed at elevated pore-water pressures or close to the groundsurface during freezing and thawing cycles.

(5)P If the stability of a site cannot readily be verified or the movementsare found to be not acceptable for the sites intended use, the siteshall be judged to be unsuitable without stabilising measures.

(6)P The design shall ensure that all construction activities in and on thesite can be planned and executed such that the occurrence of anultimate or serviceability limit state is sufficiently improbable.

(7)P Slope surfaces exposed to potential erosion shall be protected ifrequired, to ensure that the safety level is retained.

(8) Slopes should be sealed, planted or protected artificially. For slopeswith berms, a drainage system within the berm should beconsidered.

(9)P Construction processes shall be taken into account as far as theymight affect the overall stability or the magnitude of movement.

(10) Potentially unstable slopes may be stabilised by: a concrete cover with or without anchorage;

an abutment of gabions, either of steel net or geotextile cages;

ground nailing;

vegetation;

a drainage system;

a combination of the above.(11) The design should follow the general principles of Sections 8 and

9.

11.5 Ultimate limit state design11.5.1 Stability analysis for slopes(1)P The overall stability of slopes including existing, affected or

planned structures shall be verified in ultimate limit states (GEO andSTR) with design values of actions, resistances and strengths,where the partial factors defined in A.3.1(1)P, A.3.2(1)P and

A.3.3.6(1)P shall be used.

slope). Cut slopes for permanent excavations shall be not steeperthan one unit vertical in two units horizontal (50-percent slope).Deviation from the foregoing limitations for cut slopes shall bepermitted only upon the presentation of a soil investigation reportacceptable to the building official.

APPENDIX JGRADING

SECTION J101GENERAL

J101.1 Scope. The provisions of this chapter apply to grading,

excavation and earthwork construction, inc luding fills andembankments. Where confl icts Occur between the technicalr equ irements o f th is chapt er and the geotechnical repor t, thegeotechnical report shallgovern.

SECTION J106EXCAVATIONS

J106.1 Maximum slope. The slope of cut surfaces shall be no steeperthan is safe for the intended use, and shall be no steeper than two unitshorizontal to one unit vertical (50-percent slope) unless the owner orauthorized agent furnishes a geotechnical report justifying a steeperslope.Exceptions:

1. A cut surface shall be permitted to be at a slope of 1.5 units

horizontal to one unit vertical (67-percent slope) provided that allof the following are met :1.1. It is not intended to support structures or surcharges.1.2. It is adequately protected against erosion.1.3. It is no more than 8 feet (2438 mm) in height.1.4. It is approved by the building code official.1.5. Ground water is not encountered.

2. A cut surface in bedrock shall be permitted to be at a slope of oneunit horizontal to one unit vertical (100-percent slope).

sheet-pile, soldier-pile, diaphragm-wall, strut, tiebacks, rakers danlain-lain, maka stabilitas galian harus ditinjau baik terhadap bahayakelongsoran global maupun bahaya heaving, pipingdan perubahanmuka air tanah untuk setiap tahapan pekerjaan galian.

(6) Kekuatan elemen-elemen dinding dan bagian-bagiannya termasukstrut, raker, atau ground anchorharus mampu menahan tegangandan deformasi yang terjadi. Nilai Minimum FK dapat diambil sesuaiTabel 2.

(7) Analisis Heave pada galian

a. Pada galian dengan dinding penahan tanah, pada dasar galianharus dilakukan analisis Angka Keamanan terhadap heave, yaitusehubungan dengan kemungkinan naiknya dasar galian, akibatdilampauinya daya dukung tanah pada taraf dasar galian olehbobot sendiri lajur tanah selebar 0,707 B yang berbatasan dengantepi lubang, ditambah dengan beban atas (surcharge) dandikurangi oleh tahanan geser sepanjang bidang batas lajur tanah,dimana B adalah lebar galian.

b. Berhubung dasar galian hanya akan terbuka untuk jangka waktuyang relatif singkat, jika parameter drained digunakan dalamperhitungan faktor keamanan, maka FK minimum dapat diambilsebesar 1.25. Untuk analisis undrained FK minimum adalah tetapsebesar 1.5 sesuai Tabel 1.

(8) Analisis Blow-In pada galian Untuk perencanaan galian dengandinding penahan tanah, pada dasar galian harus dilakukan analisisterhadap blow-in, dengan FK=1.25.

(9) Untuk galian dengan dinding penahan galian berupa dindingsheetpile, soldier piles, atau diaphragm wallyang diperkuat denganground anchor, maka perlu dilakukan analisis stabilitas dan

kekuatan elemen-elemen ini dengan ketentuan FK minimum dan UjiPembebanan sesuai Tabel 3.

(10) Sistem fondasi dan/atau struktur penahan lateral tidak bolehmengganggu stabilitas dan deformasi tanah di lokasi bangunandan sekitarnya, baik selama masa pelaksanaan pembangunanmaupun selama masa layanan.

(11) Dampak dari sistem fondasi yang mencakup pekerjaanpenggalian, pekerjaan penahan tekanan tanah lateral,pemancangan dan pemboran tiang, pemasangan dinding penahantanah beserta angkur dan elemen penahan lateral terkait, danpekerjaan pengeringan air, serta semua elemen yang tercakupdalam sistem fundasi harus dapat dibatasi sehingga tidakmengakibatkan kegagalan ataupun deformasi di luar batas yangdiijinkan pada fasilitas bangunan di sekitar lokasi.


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NOTE The values of the partial factors may be set by the National annex. Therecommended values for persistent and transient situations are given inTables A.3, A.4 and A.14.

(2)P In analysing the overall stability of the ground, of soil or rock, allrelevant modes of failure shall be taken into account.

(3) When choosing a calculation method, the following should beconsidered:

soil layering;

occurrence and inclination of discontinuities; seepage and pore-water pressure distribution; short- and long-term stability; creep deformations due to shear; type of failure (circular or non-circular surface; toppling; flow); use of numerical methods.(4) The mass of soil or rock bounded by the failure surface should

normally be treated as a rigid body or as several rigid bodiesmoving simultaneously. Failure surfaces or interfaces between rigidbodies may have a variety of shapes including planar, circular andmore complicated shapes. Alternatively, stability may be checkedby limit analysis or using the finite element method.

(5) Where ground or embankment material is relatively homogeneousand isotropic, circular failure surfaces should normally be assumed.

(6) For slopes in layered soils with considerable variations of shearstrength, special attention should be paid to the layers with lowershear strength. This may require analysis of non-circular failuresurfaces.

(7) In jointed materials, including hard rock and layered or fissured soils,the shape of the failure surface can partly or fully be governed bydiscontinuities. In this case analysis of three dimensional wedgesshould normally be made.

(8) Existing failed slopes, which can po tentially be reactivated should beanalysed, considering circular, as well as non-circular failuresurfaces. Partial factors normally used for overall stability analysesthen need not be appropriate.

(9) If the failure surface cannot be assumed to be two-dimensional, theuse of threedimensional failuresurfaces should be considered.

(10) A slope analysis should verify the overall moment and verticalstability of the sliding mass. If a method of slices is used andhorizontal equilibrium is not checked, the inter-slices forces shouldbe assumed to be horizontal.

(11)P In cases where a combined failure of structural members and theground could occur, ground-structure interaction shall beconsidered by allowing for the difference in their relative stiffnesses.Such cases include failure surfaces intersecting structural members

such as piles and flexible walls.(12) Since a distinction between favourable and unfavourable gravity

loads is not possible in assessing the most adverse slip surface,any uncertainty about weight density of the ground should beconsidered by applying upper and lower characteristic values of it.

(13)P The design shall show that the deformation of the ground underdesign actions due to creep or regional settlements will not causeunacceptable damage to structures or infrastructure sited on, in ornear the particular ground.

11.5.2 Slopes and cuts in rock masses (Tidak Dipakai)

(12) Beban stabilitas galian dan penahan lateral harus ditinjau terhadapbeban yang berada pada jarak dari tepi galian sebesar minimalsama dengan kedalaman galian.

(13) Dalam hal pekerjaan penggalian, pekerjaan penahan tanah lateral,

pemboran tiang, serta pekerjaan pengeringan air tanah(dewatering) tidak boleh mengakibatkan terjadinya beban yangmelampaui kapasitas semula atau deformasi di luar batas toleransifasilitas yang ada di sekitar lokasi.

(14) Apabila dilakukan penggalian pada lokasi yang sudah ada fondasitiang bor atau tiang beton bertulangnya, maka tiang yang adaharus ditinjau terhadap beban tarik yang mungkin akan timbulakibat naiknya permukaan tanah sebagai akibat berkurangnyategangan vertikal efektif.

(15) Apabila dilakukan penggalian pada lokasi yang sudah ada fondasitiangnya, maka beban tambahan akibat galian tersebut harusditambahkan dalam analisis sistem fondasi terhadap beban lateral.

(16) Gambar-gambar perencanaan struktur dinding penahan tanahharus meliputi:1) Lay-out/denah dan potongan2) Dimensi-dimensi struktur berikut sambungan batang penopang

(struts) atau penopang miring (inclined bracing), jangkar tanah(ground anchor) dengan struktur penahan tanah

3) Detail-detail yang diperlukan


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11.5.3 Stability of excavations(1)P The overall stability of the ground close to an excavation, including

excavation spoil and existing structures, roads and services shall bechecked (see Section 9).

(2)P The stability of the bottom of an excavation shall be checked inrelation to the design pore-water pressure in the ground. For theanalysis of hydraulic failure (see Section 10).

(3)P Heave of the bottom of deep excavations due to unloading shall beconsidered.

11.6 Serviceability limit state design(1)P The design shall show that the deformation of the ground will not

cause a serviceability limit state in structures and infrastructure onor near the particular ground.

(2) Subsidence of the ground due to the following causes should beconsidered: change in ground-water conditions and corresponding pore-

water pressures; long-term creep under drained conditions; volume loss of deep soluble strata; mining or similar works such as gas ex traction.

(3) Since the analytical and numerical methods available at present donot usually provide reliable predictions of the deformation of anatural slope, the occurrence of serviceability limit states should beavoided by one of the following: limiting the mobilised shear strength; observing the movements and specifying actions to reduce or

stop them, if necessary.

11.7 Monitoring(1)P The ground shall be m onitored using appropriate equipment if:

it is not possible to prove by calculation or by prescriptivemeasures that the occurrence of the limit states given in 11.2 issufficiently unlikely;

the assumptions made in the calculations are not based onreliable data.

(2) Monitoring should be planned to provide knowledge of: ground-water levels or pore-water pressures in the ground, so

that effective stress analyses can be carried out or checked; lateral and vertical ground movements, in order to predict

further deformations; the depth and shape of the moving surface in a developed slide,

in order to derive the ground strength parameters for the designof remedial works;

rates of movement, in order to give warning of impending

danger; in such cases a remote digital readout for theinstruments or a remote alarm system may be a ppropriate.

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