بررسي عوامل موثر بر مقاومت برشي خاك ها در آزمايش برش مستقيم چند مرحله اي

Multistage Of Direct Shear Test or MDST

In many industrial and constructional developing countries, a safe and solid bed of rock and soil is required. An understanding of geotechnical soil properties is very important. To determine the stability of slopes, the limiting stress on the retaining wall, sinking structures, etc., obtaining the shear strength parameters of soil is necessary. Shear strength parameters of soil can be obtained from triaxial tests, direct shear test, vane shear test as well as unconfined compression test. The results of shear strength of soil that are obtained from direct shear tests using standard procedures are highly costly and time consuming. To reduce the cost and time of direct shear tests, multi-stage direct shear test can be suggested, in which can be obtained useful results in less time than the standard procedures. The procedure for multi-stage direct shear test is the same direct shear using standard procedures. The difference is that in multi-stage direct shear test instead of several samples using standard procedures, only one sample with several different overhead can be tested. Of course, this test should be done with double precision and considering some points in order that the acceptable results and comparable with standard tests to be obtained. In this research, multi-stage direct shear tests and how analysis of the data is taken into consideration. According to the direct shear tests using the multi-stage, standard procedures carried out in several projects, the desired results have been achieved. So that without unloading from the sample, tests have been conducted and the multi-stage results desired and closer to the standard procedures have been obtained.

In many industrial and constructional developing countries, a safe and solid bed of rock and soil is required. An understanding of geotechnical soil properties is very important. To determine the stability of slopes, the limiting stress on the retaining wall, sinking structures, etc., obtaining the shear strength parameters of soil is necessary. Shear strength parameters of soil can be obtained from triaxial tests, direct shear test, vane shear test as well as unconfined compression test. The results of shear strength of soil that are obtained from direct shear tests using standard procedures are highly costly and time consuming. To reduce the cost and time of direct shear tests, multi-stage direct shear test can be suggested, in which can be obtained useful results in less time than the standard procedures. The procedure for multi-stage direct shear test is the same direct shear using standard procedures. The difference is that in multi-stage direct shear test instead of several samples using standard procedures, only one sample with several different overhead can be tested. Of course, this test should be done with double precision and considering some points in order that the acceptable results and comparable with standard tests to be obtained. In this research, multi-stage direct shear tests and how analysis of the data is taken into consideration. According to the direct shear tests using the multi-stage, standard procedures carried out in several projects, the desired results have been achieved. So that without unloading from the sample, tests have been conducted and the multi-stage results desired and closer to the standard procedures have been obtained.