1.1 This practice describes an in-situ direct shear test performed on the wall of a borehole using an expandable probe. The test provides information about the strength characteristics of the soil for use in design of foundations and other earth works or forensic investigation of failed slopes, embankments, dams or other earth works. To obtain reliable results, the disturbance to the borehole wall must be minimized. 1.2 This practice covers the procedure for drilling the borehole, inserting the probe, and performing borehole shear tests in soils and weak rock but does not include high pressure testing in hard rock. This practice applies best to sands, silts, clays, and weak rocks, which will maintain an open borehole or which can be held open with drilling fluid. 1.3 Two alternate testing procedures are provided as follows: Method A: Multi-Stage Testing Method and Method B: Single-Stage Testing Method 1.4 This practice includes an alternate for obtaining pore-water pressure measurements during performance of the test. 1.5 This practice includes specific instructions for the reduction of borehole shear test data to obtain the shear strength parameters of the soil. It does not specify how the engineer shall use these properties.
This standard is needed to provide guidance on the proper execution of Borehole Shear Tests and interpretation of the resulting data. It will be used by Geotechnical engineers to obtain in-situ measurement of soil shear strength parameters for design or analysis.
Borehole Shear Test; BST; Automated Borehole Shear Test; ABST; drill holes; shear strength; in-situ; soil tests
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
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