Soil Mechanics Testing Equipment

One of the most common testing procedures of Soil Mechanics involve testing the rate and magnitude of consolidation by which the soil decreases in volume. Consolidation involves the decrease in water content of a saturated soil without replacing the water by air. The extraction of water through the application of static loads allows for further analysis regarding the stress impacted on soil samples. Following a consolidation test, the next most common test performed is to determine the shear strength of a soil material. Shear strength allows for the calculation of the magnitude of shear stress that a soil can sustain. The shear resistance of a soil sample is directly related to the result of friction and the interlocking of particles.

Check out our complete line of Soil Mechanics testing equipment.

Further tests are available for the testing of Soil samples which will allow for further analysis of the mechanical properties. Contact your NextGen representative today to further discuss how we can be your Quality Control solution.

What Soil Mechanics Testing Measures

Soil is tested for three things that design depends on: how much strength it has, how much it settles, and how it responds to repeated loading. Strength is reported from direct shear, triaxial or vane tests. Settlement comes from consolidation tests, where a laterally restrained specimen is loaded in steps while the compression and its rate are recorded. Dynamic behavior, such as the stiffness and damping that earthquake and traffic analysis needs, comes from cyclic triaxial and resonant column testing. Moisture content sits behind all of them, because compaction, consistency and strength are reported against it.

Standards for Shear, Consolidation and Triaxial Testing

Direct shear of soil under consolidated drained conditions follows ASTM D3080, with AASHTO T 236 and BS 1377-7 as related references. ASTM D5321 and EN ISO 12957 cover the interface between soil and a geosynthetic. Incremental consolidation follows ASTM D2435 and BS 1377-5.

Triaxial testing is divided by drainage condition: ASTM D4767 for consolidated undrained tests with pore pressure measurement, ASTM D2850 for unconsolidated undrained tests and ASTM D7181 for consolidated drained tests. Load-controlled cyclic response is covered by ASTM D5311, and ASTM D4648 describes the laboratory miniature vane shear test for saturated fine-grained soil.

What Affects Soil Test Results

Several decisions are made before the motor starts. In direct shear, the box has to be large enough for the largest particle in the specimen, because a few coarse stones can bridge the shear plane and the result then describes those stones rather than the soil. The normal stress also has to stay where it was set while the specimen changes volume, which pneumatic closed loop loading is designed to handle. The direct shear guide explains both points.

In triaxial and consolidation work, specimen disturbance, saturation and the drainage condition decide which parameters the result supports. A consolidation series can run for days, so every load change made by hand is a chance for it to drift. Shear and triaxial methods are not interchangeable without engineering review, so match the test to the drainage assumption in the project.

Soil Testing Equipment from NextGen

Consolidation is covered by the NG-Oedometer and the automatic ACE oedometer. Direct shear is covered by the Shearmatic, the NG-Shear DGEN and the Shearmatic 300 for samples up to 300 mm square, with the laboratory vane apparatus for soft soil. Triaxial work runs on the automatic triaxial system and the dynamic triaxial system, and the resonant column and torsional shear tester measures small-strain dynamic properties.

The MULTISPEED handles displacement-controlled tests, and the GenMoist balance measures moisture. Each system is installed and calibrated by NextGen engineers, your team is trained on the procedures, and support continues for the life of the apparatus.