METHOD FOR IN-SITU GROUND STRAIN CHARACTERISTICS DETERMINATION Russian patent published in 2006 - IPC E02D1/00 

FIELD: investigation of foundation soil in situ, particularly to construct and reconstruct existent buildings and building structures.

SUBSTANCE: method involves lowering die connected to lower pipe string end in borehole for predetermined test depth; performing ground test by applying load in predetermined stages with the use of die; measuring change of specific load applied to ground with the use of dynamometer installed between upper pipe string end and rigid anchor means on day surface before test performing; measuring ground settlement under the action of above load at time intervals set by test program. Ground settlement is measured with the use of linear displacement sensor installed on reference means on day surface and brought into cooperation with pipe string. If conditional stabilization is achieved one may shift to the next stage and process test result with the use of standard procedure. The die is made as screw member with single blade. The die is lowered to predetermined test depth by screwing thereof into borehole. Hydraulic jack is provided with rod travel limiter. The load is applied up to predetermined deformation value obtaining by hydraulic jack body position fixation relative anchor means along with following ground strain release at each test stage. As additional ground settlement under the die increases the ground settlement is reduced at each stage to approximate value thereof to that at predetermined deformation stage but not to reach thereof.

EFFECT: reduced ground investigation time.

3 cl, 3 dwg