Bore Hole Shear Test
Soil is a critical component of any construction project. Engineers need to understand the strength of the soil in order to design stable structures, such as foundations, retaining walls, and slopes. In-situ methods of testing soil strength are useful for obtaining accurate and reliable information about the soil's properties.
One such method is the borehole shear test (BST). The BST is an in-situ method of assessing the drained shear strength of soil. The test involves drilling a borehole and loading the sides of the boring with plates. A normal load is then applied to the plates, and the soil is allowed to consolidate. The plates are then raised, thus shearing the adjacent soil, and the equipment provides a direct measurement of shear strength.
The BST is a robust and simple method of testing soil strength that provides accurate and reliable results. Unlike some other methods, the BST provides a direct measurement of shear strength and has the potential to provide high quality in-situ test data at a reasonable cost.
To evaluate the effectiveness of the BST, a range of soils were tested in-situ using this method, and laboratory tests were conducted on undisturbed samples of the same soils for comparison. All of the soils tested were unsaturated, but customary practice requires the saturated shear strength for design. Therefore, laboratory tests were conducted at both the in-situ and saturated conditions.
The results of the study showed that the BST shear strength parameters had only modest agreement with those obtained from direct shear tests on soaked samples and triaxial tests on backsaturated samples. This indicates that caution should be exercised when interpreting the results of the BST and that laboratory tests may still be necessary for design purposes.
In conclusion, the borehole shear test is a valuable method for assessing the drained shear strength of soil in-situ. However, it is important to keep in mind that the results may not always agree with laboratory tests, and further evaluation may be necessary to ensure accurate design of construction projects.