Geotest offers a wide variety of permeability and triaxial equipment ranging from basic manual to automatic data acquisition and full computer control. These listings and descriptions present highlights and attempt to differentiate Geotest equipment from comparable equipment of other makes. Among these differences is the use of platens measuring 2.875", the size actually ejected from 3" thin wall tubes, instead of 2.8". Another is the use of 2,000 lbf (10Kn) capacity load frames which we believe are more than adequate for samples up to 4" (100mm) diameter. Higher capacity load frames are also offered, but generally are not needed and add extra expense.
Geotest control panels feature simplicity of operation, strong technical backup for inexperienced technicians and fast test results. Both type control panels conform to ASTM D5084 for flexible wall permeability testing and are equally suitable for triaxial compression testing in accordance with ASTM D2850 and D4767. Both have low air consumption. For that reason these panels do not include venturi type vacuum pumps which require large amounts of air to achieve relatively low vacuums. Two small vacuum pumps are offered as options. Either panel can be used to pressures as high as 300 psi (2,000kPa). Geotest systems assume one panel for each cell. This permits complete flexibility when setting all pressures. Systems using add-on panels require cells being conditioned to have identical pressures. All valves and fittings are highest quality available.
Geotest cells have the least piston friction of any commercial triaxial cell that does not permit liquid to leak past the piston. We go a step beyond ASTM D2850 which permits the piston to be guided by 2 linear ball bushings. The ASTM system is excellent except that these cells must be sealed against leakage. The usual method is a ´U´-cup seal which presses against the piston. Friction increases each time the lateral pressure goes up. Piston friction on a Geotest cell never changes. The piston will slide down by its own weight. This minimal friction never changes despite high applications of lateral pressure.
The triaxial and permeability cells are identical except for the top. For a complete description of the features, please see Triaxial Cell Features (S5020-44).