scope:

This document deals with field testing with borehole jack test as part of geotechnical investigation and testing according to EN 1997-1 and EN 1997-2. The present document describes the procedure for conducting a borehole jacking test in natural soils, treated or untreated fills and in very hard soils, soft rocks (EB 1 000 MPa) or jointed rocks either on land or off-shore. The borehole jacking test is performed by the diametrical opening of two cylindrical steel loading plates placed in the ground. Pressure applied to, and associated opening of the probe are measured and recorded so as to obtain a stress-displacement relationship of the ground as tested in the range of the expected design stresses (see Figure 1).