Geotechnical investigation and testing - Field testing - Part 16 : Borehole shear test
This document is applicable to the borehole shear test using the phicometer procedure, commonly named the phicometer test (etymologically derived from phi for friction angle, co for cohesion and meter for measurement).
The test can be performed in all types of natural soils, fills and artificial soils, which can be saturated or not.
It does not apply to very soft fine soils, very loose coarse soils, medium strong to very strong rocks and natural or artificial soils with a predominance of cobbles having a particle diameter greater than 150 mm.
Generally, the test is applicable in soils with an order of magnitude of their in situ resistance characteristics as follows:
— Ménard pressuremeter limit pressure: 0,4 MPa < plM < 3,5 MPa approximately or more than 4 MPa in granular non-cohesive soils;
— CPT Cone resistance: 1,5 MPa <qc <15 MPa approximately, depending on the type of soil (see Annex E);
— SPT N: 8 <N <50 approximately, depending on the type of soil (see Annex E).
The test can also be carried out in soils presenting a resistance outside these application limits as long as the representativeness of the results is assessed or validated by the analysis of the PBST graphs (see Clause 8).
This document applies only to tests carried out at a depth less than or equal to 30 m.
The parameters derived from this test are the shear strength properties, as the cohesion and angle of friction.