Triaxial Lab Report Example | Topics and Well Written Essays - 1250 words

Triaxial - Lab Report Example The clisp studio was then set up followed by completing the Pressurising Triaxial Cell checklist. The test stages were then made to run. After completing the stages, the test was terminated using the Clip Studio. The next procedure was completing the Draining Triaxial Cell checklist. The end point was the mohr cicle, for each of the sampled, the angle of shearing resistance of the soil and the apparent cohesion Introduction The triaxial shear test is a method that is commonly used in measuring the mechanical properties of deformable solids such as rock, granular materials, powder, and soil (Byrne 34). For loose granular material such as gravel or sand, the material is often contained in cylindrical latex sleeve with platen closing off the bottom and top ends (Byrne 25). Such as cylinder is immersed in a water bath or any other fluid, which provides pressure along the cylinder sides. Then the top platen is mechanically driven along the cylinder axis with a view to squeeze the material . Generally, there are a number of variations on the test. Although the term triaxial tends to suggest that stresses may be different in 3 directions, this may not be true. In this test with water or oil as a confining medium, confining pressures are all equal in all the directions. This means that for a compressed test, in principle stresses, for compression test, ?1 ? ?2 = ?3, while for tensile test, ?1 = ?2 ? ?3) (Chen 32). Therefore, it is only in true triaxial test that the stresses in all directions (?1 ? ?2 ? ?3) can be different. The distance travelled by the upper platen is then measure as a function of force needed to push it while the pressure of the water surrounding it is carefully controlled (Chen 24). For cohesive materials such as rock, and clay, the test is quite similar to that of loose granular materials (Ferrari 56). However, the test for cohesive materials takes more time than the test for loose materials. For testing of rocks, the sleeve is always a thin metal sheet rather than latex. It is rare to perform a triaxial testing on a rock because the high pressures and forces has to break the rock sample. This is makes it cumbersome and costly.This experiment was focused on undrained triaxial compression test (Ferrari 44). The aim of this lab experiment was to determine the undrained shear strength of soil using triaxial compression test. Procedure The sample was extruded from a tube and trimmed to size with the diameter of the soil as 38mm and its leagth of 76mm. The sample was sleeved with a rubber membrane. The sample was placed on the pedestal at the botton side of the seal and cell using a rubber ring. The loading cap was then placed at the top of a sample and sealed with rubber ring. The top drainage tube was then secured. The cell was mounted over the sample and filled according to the flooding Triaxial cell checklist. The clisp studio was then set up followed by completing the Pressurising Triaxial Cell checklist. The test stages were then made to run. After completing the stages, the test was terminated using the Clip Studio. The next procedure was completing the Draining Triaxial Cell checklist. Results In this lab experiment, the moisture content were calculated as shown in table 1 Table 1: Moisture content Container No. 1 2 3 4 Mass of wet soil + container (m2) g 75.4 48.2 N/A N/A Mass of dry soil + container (m3) g 63.2 42.0 N/A N/A Mass container (m1) g 5.2 5.4 N/A N/A Mass of moisture