The shear box test on soil - Essay Example

The shear box test has an advantage over test because of the simplicity of equipment used and the ease in setting it up. The Shear test box also tests soil samples under different conditions such as consolidation, drainage, and saturation conditions. Another advantage of the shear box test is that it is easy to visualize what is happening to the soil as the test is being carried out. Various processes using the shear box test determine these properties. In determining the soil, these properties the results of the test are tabulated and graphs are drawn.

Interpretation of the graphs is what gives significant meaning to some of the soil properties being studied. Purpose of the test A shear box test is used in geotechnical engineering to test various properties of soil. These soil properties include; friction angle, peak shear strength, soil cohesion, and the residual shear strength of the soil being studied. The key purpose for carrying out the test is to enable geotechnical engineers decide on the consolidated-drained shear strength of a silt to sandy soil.

Shear strength is a very important aspect in engineering when determining soil properties. This is because most structures are based on soil’s shearing strength or resistance. Therefore, any time a structure is to be constructed it is important that the soil’s shear resistance be analyzed as the first step to decide on the whether it will be possible to construct. The shear strength of a discontinuity is considered to be of lower strength when compared to blocks with intact material between the discontinuities.

These important facts and the results of shear tests enable the engineers to determine important aspects of engineering. These include determining the bearing dimensions for foundations, computing the stability of cuts and slopes, and in finding the amount of pressure that an area of soil exerts on the wall it retains (Price & De Freitas, 2009, p. 361). Brief description of the test set up The Apparatus “A definitive test apparatus mainly consists of the following apparatus. Rigid split box that has a top and a bottom these are place inside a shear box carriage, which is box, shaped.

The carriage rests on a pair of rollers that are aligned to move along two grooved tracks. The shear apparatus is controlled by a motor, which is also connected in the apparatus” (Huat, et al., 2005, p. 1284). The set up The test is carried out on three or four specimen taken from a comparatively undisturbed soil samples. The set-up of the test experiment follows the following procedures: 1. The first step is to weigh the initial mass of the soil sample 1. Next is to take the shear box’s measurements that are the diameter and height 2.

From the measurements calculate what 15 percent of the diameter will be in millimeters 3. Next step involves assembling the shear box and placing it into the shear device. 4. Place a porous stone and a filter paper into the shear box 5. Pour the soil sample, for example sand, inside the shear box and remove the top layer to ensure it is level 6. Put a porous stone on top of the sand then cover it with a filter paper and then place the top plate which usually has a ball 7. After that take away the alignment screws that are in the shear box and using these screws open the gap that is between the two shear box halves to 0.

025 inches. After that remove the screws from the gaps 8. Take the weight of the soil again and calculate the total mass of soil used 9. Finish assembling the device and set the three