METHOD AND DEVICE FOR GROUND TESTING BY ROD PUNCH Russian patent published in 2007 - IPC E02D1/00 

FIELD: investigation of foundation soil in situ, particularly quick ground testing by applying static load thereto in prospecting shafts drilled in building under reconstruction and in construction pitches.

SUBSTANCE: method involves embossing die made as rod preferably having diameter d of 5-20 mm and provided with dynamometer in upper part thereof in ground under the action of static load applied thereto by operator's hand; recording depth of rod immersion in ground and die immersion force. Operator presses upon double-console arm secured to dynamometer. It has been found experimentally that at a given rod die cross-sections specific clay ground adherence or the square of internal sand friction angle tangent φ are proportional to depth h of die immersion and immersion force in clay ground F_c and in sand ground F_s generated as a result of rod die embossing. F_c=k₁·h·c, F_s=k₂·h²·tg²φ, where k₁ and k₂ are dimensional experimentally determined proportionality coefficients. Deformational ground characteristics are determined from experimentally established conditions, which fix that sand stress-strain modulus E_s is proportional to square of internal sand friction angle tangent φ and clay stress-strain modulus E_c is proportional to specific clay ground adhesion c. E_s=B·tg²φ, E_c=D c. It can be tolerated that B=60 MPa for sand, D=800 for loam and D=400 for clay at any sand particle size and porosity and at any clay ground consistence.

EFFECT: possibility to estimate ground deformability by stress-strain modulus determining by express-method.

3 cl, 6 dwg