The instructional geotechnical laboratory is used to conduct laboratory sessions that are part of the coursework for undergraduate classes. The lab consists of five triaxial cell setups which can also be used for conventional triaxial tests (CU, CD, UU) as well as consolidation tests, a direct shear apparatus, constant head and falling head permeability setups, and a mechanical sieve shaker.
Equipment is also available for standard soil classification tests. This laboratory includes an instructional centrifuge, housed in the undergraduate geotechnical laboratory. Although this centrifuge has been in operation since 1996, it was completely refurbished using a grant from NSF during the summer of 2004 to accommodate symmetrical swinging baskets, video data acquisition system, and a high performance AC drive motor.
This centrifuge is primarily used as an instructional tool in undergraduate geotechnical engineering labs to introduce simple concepts taught in undergraduate geotechnical courses, including slope stability, active and passive earth pressure conditions, foundation bearing capacity module, and a mechanically-stabilized earth walls.
The geotechnical group at the University of Colorado at Boulder is also equipped with a cluster of advanced testing equipment suitable for characterization of soils and geosynthetics under static, cyclic, and dynamic applications. A geosynthetic pullout box adapted for the 22 kN testing machine can be used to evaluate the interface shear and pullout resistance of geosynthetics in unsaturated soils.
The laboratory includes 6 cubical cells of different sizes and load capacities which can be used to control the complete principal stress state in a cubical soil, rock, or concrete specimen, with proportional or non-proportional loading under static or cyclic conditions. The largest cubical cell (18 cm side length) has been adapted to evaluate thermally induced water flow in unsaturated soils and to characterize thermally induced volume change in soils under different states of stress.
The laboratory also includes specialized devices which were developed to characterize the thermal properties of soils, concrete, and rock. This includes an oedometer with temperature control to measure thermal-induced consolidation of soils, a triaxial cell incorporating a thermal-needle to measure thermal conductivity as a function of void ratio, and a 3 Hoek cells constructed from high strength aluminum which can be placed within an environmental chamber.
The laboratory also contains a large-scale directional shear apparatus for evaluating anisotropy effects on soil strength, equipment designed for triaxial testing at low confining pressures, a cyclic triaxial cell with local strain measurement capabilities, two resonant column devices for unsaturated soils with flow pump suction control, and bender elements for pulse-wave testing.
A state-of-the-art flow processes laboratory is equipped with custom-made testing equipment used for studying flow phenomena in soils. Three flow pumps for precisely controlling flow rates are connected to modified triaxial cells in which various tests with saturated, unsaturated, and multiphase flow are performed.
Typical tests performed in this laboratory include hydraulic conductivity of saturated and unsaturated soils, seepage-induced consolidation of soft soils, and multi-phase flow experiments. This laboratory is also equipped with conventional unsaturated soils testing equipment for determination of the soil water retention curve (rigid and flexible wall pressure chamber outflow devices and hanging column devices).