The borehole shear test (BST) is an in-situ test method to estimate shear strength and its parameters of geomaterials (i.e., cohesion and friction angle). The shear plate with wedges is an important component of the BST for shearing the ground. It is well known that the wedge type of the shear plate affects the shear strength evaluation; therefore, various wedge types of shear plates have been developed according to target geomaterials (i.e., clay, silt, sand, and rock). However, a wedge type for intermediate geomaterials, such as highly to completely weathered rock and residual soil, has not yet been developed. In this study, a series of modified shear tests (MSTs) simulating the shearing mode of the BST was conducted on highly to completely weathered granite and very dense residual soil. The effect of wedge spacing on the shear strength and parameters was evaluated with varying wedge spacings of the shear plate. The MST results were compared with the results of the direct shear test (DST) to determine the optimal wedge spacing for the highly to completely weathered rock and residual soil. The optimal wedge spacing-to-wedge length ratio was determined to be 5 since the shear plane was clearly formed between the wedges, and the shear strength and parameters agreed well with the results of the DST in the case of a wedge spacing ratio of 5.
Influence of Borehole Shear Test Wedge Spacing on Shear Strength Parameters of Intermediate Geomaterials
KSCE J Civ Eng
KSCE Journal of Civil Engineering ; 28 , 8 ; 3137-3150
2024-08-01
14 pages
Article (Journal)
Electronic Resource
English
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