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Geotechnical Testing: Tests & Capabilities

Our fully automated laboratory is equipped with two triaxial load frames with flow pumps where we can apply effective confining stresses up to 400 psi. We are capable of performing multi-stage, iso & anisotropic (kO) consolidation, triaxial extension tests, and we’re familiar with the SHANSEP method. We have 13 traditional 1-D consolidation frames and constant rate of strain consolidation capabilities. With our three direct shear boxes we can determine peak and residual strength for single and multi-stage specimens. We also have the ability to perform direct simple shear (DSS).

In addition to this we have 56 triaxial permeability chambers with permeameters for fastest turnaround time possible. TRI also has the ability to determine soil water characteristic curves for unsaturated soils. In addition to our advanced geotechnical testing capabilities we also have the ability to perform classification, granular permeability, Proctor and index density testing.

Shear Strength

RELEVANT STANDARDS
ASTM D2166 Unconfined Compression
ASTM D2850 Unconsolidated Undrained (UU/Q) Triaxial Compression
ASTM D3080 Direct Shear of Soil
ASTM D4767 Consolidated Undrained (CU/R_bar) Triaxial Shear
ASTM D6528 Direct Simple Shear
ASTM D7181 Consolidated Drained (CD/S) Triaxial Shear with Volume Change

TRI has the ability to extrude or remold soil samples for a large variety of diameters ranging from 1.4 to 6 in. (36 – 150 mm) to determine the shear strength of the material. TRI operates twenty 2000 lb (8.9 kN), two 5000 lb (22 kN), and one 40k lb (180 kN) fully automated load frames with ten flow pumps capable of applying effective stresses up to 500 psi (3,500 kPa) for performing a large variety of geotechnical shear strength testing. TRI maintains a direct simple shear apparatus and nine direct shear devices (2.5 in/63.5 mm diameter). In addition to isotropically and anisotropically consolidated triaxial compression/extension and, TRI also performs multi-stage triaxial testing.

Consolidation

RELEVANT STANDARDS
ASTM D2435 Consolidation – Incremental 1-D
ASTM D4186 CRS Loading 1-D
ASTM D4546 1-D Swell Potential
ASTM D4829 Expansion Index
ASTM D5333 Collapse Potential
Triaxial Ko Triaxial Consolidation

TRI operates 12 fully automated 1-D consolidation frames that are capable performing custom loading schedules with loading pressures in excess of 64,000 psf (3,000 kPa). Our capabilities also include secondary compression (cα) analysis, constant rate of strain (CRS, three cells), swell potential, expansion index, and collapse potential analysis.

Hydraulic Conductivity

RELEVANT STANDARDS
ASTM D2434 Hydraulic Conductivity of Granular Soils, Fixed Wall (diameter 2.5-7.0 in.)
ASTM D5084 Hydraulic Conductivity of Fine Grained Soils, Flexible Wall (diameter 1.4-6.0 in.)

TRI has the capability to determine the permeability of soil and aggregates over a large range of velocities ranging from 1 x 10-11 cm/sec to 300 cm/sec. Field samples are extruded and mounted in the laboratory in one of our 55 triaxial permeability cells (Diameters 1.4 to 6 in., or 36 mm to 150 mm) with results often reported within 1-2 days depending on the sample’s initial saturation. For effective stresses less than approximately 5 psi (34 kPa) flow pumps are utilized to control the effective stress during backpressure ramping. For effective stresses greater than approximately 50 psi (340 kPa) and upwards of 400 psi (2,800 kPa) flow pumps are often utilized in concert with aluminum walled cells. The hydraulic conductivity of sand and gravel samples is measured in a variety of fixed wall cells utilizing manometers along the sample length to directly measure head losses. TRI is capable of testing up to approximately one-inch minus coarse grained material and is capable of applying confining loads during permeation.

Unsaturated Soil Mechanics

RELEVANT STANDARDS
ASTM D5298 Soil Potential/Suction via Filter Paper
ASTM D6836 Unsaturated Soils – Soil Water Retention

TRI performes unsaturated soil mechanics testing to support evapotranspirative cover systems, foundation design and field instrumentation and monitoring. TRI has the ability to determine the full soil water characteristic curve using a variety of methods that include hanging column, pressure plate, chilled mirror hygrometer, and humidity chamber. TRI can also perform column studies for multi-layered soil system interaction including capillary break evaluation. TRI has the capabilities to make laboratory measurements to support design of structures on expansive soils including TxDOT’s PVR methodology, PTI, and BRAB. We also have the ability to provide soil specific calibrations of suction-based and volumetric-based field instrumentation equipment for field deployment.

Rock Mechanics

TRI is capable of determining index and shear strength properties of rock interfaces and intact rock. Shear strength capabilities include testing of rock interfaces and intact rock in direct shear, unconfined, and triaxial stress states. TRI has the ability to impart a load of up to 100,000 lb (440 kN) in compression and in shear. TRI also performs testing for the evaluation of tunnel boring machine cutter wear and rock excavatability.

RELEVANT STANDARDS
ASTM D3967 Indirect Tensile / Brazilian
ASTM D4543 Dimensional Tolerances for ASTM D7012
ASTM D4644 Slake Durability
ASTM D5084 Hydraulic Conductivity of Rock Cores, Modified Method
ASTM D5607 Direct Shear of Natural or Saw-Cut Rock Interface
ASTM D5731 Point Load Strength Index
ASTM D5873 Rock Hardness by Schmidt/Rebound Hammer
ASTM D7012 Compressive Strength
A – Undrained Triaxial Compression (ASTM D4543 Preparation)
B – Undrained Triaxial Compression with Elastic Moduli
C – Unconfined, Peak Load Only
D – Unconfined, with Elastic Moduli
ASTM D7625 CHERCHAR Abrasivity
Punch Indent Punch Indentation/Penetration – Dollinger & Handewith 1998, Round & Conical

Analytical Chemistry

TRI performs chemical analysis of soil samples for soil corrosion, thermal conductivity, and leachate analysis in support of geotechnical projects. TRI utilizes spectrographic methods and wet methods for analysis. TRI maintains laboratory grade equipment for testing and is capable of performing additional testing methods upon request.

RELEVANT STANDARDS
AASHTO T288 Min. Electrical Resistivity
AASHTO T290 Water Soluble Sulfate
AASHTO T291 Water Soluble Chloride
ASTM C289 Potential Alkali-Silica Reactivity, Wet Chemical
ASTM C837 CEC of Clay – Methylene Blue Index
ASTM C1580 Water-Soluble Sulfates, Water Extraction
ASTM D512 Water-Soluble Chloride, Water Extraction
ASTM D516 Water-Soluble Sulfates, Water Extraction
ASTM D1411 Water Soluble Chloride Ion
ASTM D4972 pH of Soil
ASTM D4978 Screening of Reactive Sulfides in Waste
ASTM D5334 Thermal Soil Properties, Dry-Back Curve Testing
ASTM D6276 Soil-Cement/Lime Mixtures – Soil-Lime Proportion by pH
ASTM G51 pH of Soil, Corrosion Testing
ASTM G57 Electrical Resistivity
ASTM G187 Electrical Resistivity
ASTM G200 Oxidation-Reduction Potential (ORP) of Soil
EPA 9045D Analytical – Soil and Waste pH
SM4500 Sulfides, Methylene Blue
Walkley Black Soil Organic Matter (Oxidation Method)

Index Properties

RELEVANT STANDARDS
ASTM C29 Bulk Density and Voids in Aggregate, Rodded Unit Weight
ASTM C88 Particle Size – Soundness of Aggregates by Use of Sodium or Magnesium Sulfate
ASTM C117 Fines
ASTM C127 Lightweight Particles
ASTM C123 Relative Density (Specific Gravity) of Coarse Aggregate
ASTM C136 Particle Size of Fine and Coarse Aggregate
ASTM C142 Clay Lumps and Friable Particles
ASTM C535 LA Abrasion of Coarse Aggregate
ASTM D422 Particle Size Analysis
ASTM D698 Moisture Density – Standard Proctor
ASTM D854 Specific Gravity
ASTM D1140 Particle Size – Percent Finer than No. 200
ASTM D1557 Moisture Density – Modified Proctor
ASTM D1883 CBR (California Bearing Ratio)
ASTM D2216 Moisture Density – Moisture Content
ASTM D2419 Sand Equivalent
ASTM D2487 Index Properties – USCS Classification
ASTM D2488 Visual Manual Classification
ASTM D3042 Carbonate Content of Aggregate – Fine Aggregate
ASTM D4221 Double Hydrometer
ASTM D4253 Maximum Index Density
ASTM D4318 Atterberg Limits (Method A – Multipoint)
ASTM D4373 Rapid Carbonate Content
ASTM D4718 Correction of Unit Weight and Water Content for Soils Containing Oversize Particles
ASTM D4791 Flat and Elongated Particles of Aggregate
ASTM D4943 Shrinkage Factors of Soils by Wax Method
ASTM D5821 Percentage of Fractured
ASTM D6572 Crumb Test for Clayey Soils
ASTM D7263 Moisture Content and Density (Unit Weight)
ASTM D7626 Loss on Ignition
DOTD TR Organic Matter in Soil Louisiana 413-10
USDA Textural Soil Classification

Specialty Testing

RELEVANT STANDARDS
ASTM D558 Soil-Cement/Lime Mixtures – Moisture-Density of Soil-Cement Mixtures
ASTM D559 Soil-Cement/Lime Mixtures – Wetting and Drying Compacted Soil-Cement Mixtures
ASTM D1429 Specific Gravity of Water and Brine
ASTM D1633 Soil-Cement/Lime Mixtures – Compressive Strength of Soil-Cement Mixtures
ASTM D4542 Soluble Salt Content
ASTM D4647 Pin Hole Dispersion
TEX-117-E TxDOT Triaxial – Accelerated Method
Viscosity Couette Coaxial Cylinder