Geotechnical &Mining Engineering

Services

Geotechnical &Mining Engineering

Services

Southwest Research InstituteSan Antonio, Texas

Southwest Research InstituteSan Antonio, Texas

®

A s an independent, nonprofit research and developmentorganization, Southwest Research Institute (SwRI®) uses a multidisciplinary, integrated approach to solvingcomplex problems in science and applied technology.

SwRI provides effective solutions to a broad range of geotechnical and mining engineering problems.Experienced staff members use state-of-the-art computer,laboratory, and field study equipment to solve diversescientific and engineering problems related to surfaceand underground structure stability.

The Institute has developed an international reputation for its expertise in thefollowing technologies:

■ Physical and earth sciences■ Material sciences and engineering■ Hazard and risk assessment■ Environmental science and engineering■ Regulatory interpretation, implementation, and compliance

demonstration

The Institute’s comprehensive services address geotechnical and mining industry needs in areas such as:

■ Numerical modeling■ Site investigations■ Laboratory testing■ Reliability analyses■ Borehole stability assessment

About the Cover Inset:Numerical simulations are used to calculate stresses and displacementsresulting from a combination of in situ stresses and thermal loads.

© 2006. Southwest Research Institute.All Rights Reserved.

Equal Opportunity Employer M/F/D/VCommitted to Diversity in the Workplace

TransformerHall Machine

Hall

18.5 m 41.75 m 22.0 m

Unsupported underground excavationsmay be unstable when subjected to mineseismic events or high stresses.

Underground excavations may also bestabilized using shotcrete.

SwRI staff have experience applying numericalmodeling to the design analysis of TransformerHall and Machine Hall in an underground cavern.

Underground excavations may bestabilized using rockbolts.

SwRI engineers assess the effectiveness of ground supports under complexground conditions using numerical models.

Numerical ModelingThe Institute develops and applies numerical modeling to solve a variety of geotechnical and mining engineering problems. Staff members have also modified available numerical codes to meetclient needs in:

■ Underground and surface structural stability assessment (for example, longwall chain and yield pillars and entry; multiple seam mining optimization; and surface slope) using continuum, discontinuum, and particle flow methods

■ Earthquake and rockburst stability determination■ Support system design and analysis including rock bolts, lining, and shotcrete■ Rock- and soil-structure interaction■ Earthquake ground response analysis■ Failure zone and progression estimation

Site InvestigationThe Institute conducts comprehensive field studies to characterize sites and evaluate effects of mining-induced seismicity on underground excavation stability. SwRI field experience includes awide range of investigations and assessments, including the following:

■ Instability prediction and monitoring under earthquake loads■ Underground pillar and entry stress and deformation measurements■ Support systems (including

rock bolt, lining, shotcrete, and soil nailings) design and effectiveness assessment

■ Rockburst and mine seismicity monitoring and investigation

■ Damage zone estimation, monitoring, and propagation assessments

■ Slope stability monitoring and assessment under gravity, hydrological, and earthquake loads

■ Surface subsidence measurements and assessments

■ Soil and rock mass classification and characterization

■ Rock fracture geometry surveying and fracture network simulation

■ Blasting-induced structural damage assessment

■ Hydrological response assessment

BEDDING

5/22/91(2.4)

(141,199)(1622)

70°

LFM95-C1Depth 1591 m

5/21/91(1.5)

(66,134)(1618)

11/11/91(2.5)

(76,221)(1615)

1/30/92(2.5)

(99,180)(1619)

3/27/91(2.6)

(88,143)(1635)

12/11/91(3.0)

(92,130)(1528)

- Seismic Event

- Event Magnitude

- Peak Particle Velocity (mm/sec)

at LFM95-c1 and LFM95-C2 site

- Depth from Surface, Meters

- Peak Particle Velocity Calculated

11/13/91(2.3)

(68,82)(1627)

LUCKYFRIDAY

VEIN

8/09/91(2.2)

(109,109)(1604)

7/31/91(2.6)

(54,60)(1742)

5/23/91(2.5)a

(173,200)b

(1622)c

LFM95-C2Depth 1598 m

3/27/92(2.0)

(113,199)(1630)

6/18/91(1.6)

(104,76)(1595)

70°

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Dim

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D0

2.6540 560 570 580 590550 600 610

Time, sec

2.7

2.8

2.9

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Institute staff members extensively instrumented sites to aidthe design of an underground hydropower facility.

SwRI engineers are developing a methodologyfor early warning of rockburst potential.

3D Model of the Excavations

Drainage Galleries

Upper ExpansionChamber

MachineHall Transformer

Hall

Draft Tube

Bus Duct

PressureTunnel

SwRI engineers monitored mining-induced seismicity greater than magnitude 1.5 on the Richter scale at a deep undergound mine.

Laboratory TestingTo understand rock and soil behavior under a variety of conditions, SwRI engineers determinephysical and mechanical properties through a battery of laboratory tests. These test results con-tribute to the design, structural modeling, and stability assessments of mines, shafts, tunnels, andvarious underground storage structures. Using methods approved by the American Society forTesting and Materials and the International Society for Rock Mechanics, SwRI performs laboratorytests on rock specimens and joints, soils and granular materials, and scale models of openings injointed rock masses. Laboratory testing services include:

■ Direct shear tests of large rock fractures and soil specimens■ Small-scale physical model tests of underground and surface structures under static and

dynamic loads■ Specialized laboratory tests, including damage assessment of underground excavations

under repetitive seismic loads■ Shear and creep tests ■ Uniaxial and triaxial compression tests for rock strength, modulus, shear wave

velocity, and compressive wave velocity measurements■ Surface profile measurement and roughness characterization

SwRI has extensive laboratory testing capabilities to evaluate potential problems in the field.

SwRI-conductedfield investiga-tions to show the stepwise closure of anundergroundexcavation as a result of mine seismicity.

An Institute laboratory experimentmeasured the deformation around anunderground excavation subject toan earthquake ground motion.

Engineers investigated the effects of mine seismicity usingstandard and customized tests.

SwRI engineers studied the effects of mineseismicity on the stability of underground excavations.

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Laboratory FacilitiesAs an internationally recognized multidisciplinary research and development organization, SwRIhas extensive laboratory facilities. The Institute has innovative and state-of-the-art facilities for per-forming a variety of geotechnical and geological evaluations including:

■ Environmentally controlled scale-model evaluation■ Rock sample preparation and physical testing■ Rock strength, modulus, and shear and compressive wave velocity measurements

Experienced SwRI engineers design and build specialized test equipment, such as this device for large-scale dynamic shear tests of natural rock fractures under earthquake loads.

A triaxial test cell enables engineers to determine a rock matrix failure envelope

under various environments including pore-pressure and heated conditions. The test cell also measures the shear

and compressive wave velocities of rocks undergoing progressive damage.

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Reliability AnalysesThe Institute conducts comprehensive reliability analyses on a variety of geological andsupport structures, including

■ Soil and rock slope■ Tunnel reliability■ Support systems

Institute engineers assess the reliability of a slope considering uncertainties relatedto slope geometry, material and fracture properties, and watertable location.

Using advanced numerical modeling, SwRI engineers assesspotential borehole breakout mechanism and recommend methods of preventing or reducing the severity of breakouts.

Borehole Stability AssessmentThe oil and gas industry is striving to reduce drilling-related costs and downtime and to enhancewell production by controlling potential borehole stability and sanding problems. SwRI engineersconduct numerical analyses to identify potential borehole failure mechanisms and to provide cost-effective solutions. SwRI provides a variety of drilling and borehole-related service support including:

■ Borehole stability estimation considering presence of weak zones, fractures, and variation of material properties

■ Mud weight estimation while drilling

■ Potential caving analysis■ Drill performance estimation■ Potential sand formation■ Material properties investigation■ Wave propagation analysis

1Factor of Safety

ProgressiveBoreholeBreakout

Minor Principal Stress

ProgressiveBoreholeBreakout

MajorPrincipalStress

MajorPrincipalStress

Boreh

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We welcome your inquiries.For more information, please contact:

Dr. Asadul H. Chowdhury, ManagerGeosciences and Engineering DivisionSouthwest Research Institute6220 Culebra Road • P.O. Drawer 28510San Antonio, Texas 78228-0510(210)522-5151 • Fax (210)522-6081E-mail: asadul.chowdhury@swri.orgWeb Site: swri.org

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Southwest Research Institute is an independent, nonprofit, applied engineering and physical sciences research and development organization using multidisciplinary approaches to problem solving. The Institute occupies more than 1,200 acres and provides nearly two million square feet of laboratories, test facilities, workshops, and offices for more than 3,000 employees who perform contract work for industry and government.

SwRI Business Development • San Antonio, Texas • (210) 522-2122 • Fax: (210) 522-3496 • E-Mail: BD@swri.org