METHOD FOR DETERMINING THE SPECIFIC RESISTANCE FORCES ON THE SIDE SURFACE OF THE FOUNDATION OF FROZEN SOILS AT DIFFERENT TEMPERATURES IN THE PROCESS OF THAWING AND APPARATUS FOR IMPLEMENTATION THEREOF Russian patent published in 2021 - IPC E02D33/00 

FIELD: building.

SUBSTANCE: invention relates to the field of building, in particular, to determining the bearing capacity of foundations in permafrost soils. The method for determining the specific resistance forces on the side surface of a pile foundation in frozen soils at various temperatures and in the process of thawing consists in the fact that frozen soil is frozen to a model of the pile foundation in the form of a rectangular plate made of the foundation material at a fixed value of negative temperature, a normal shear load is applied to the plate, pressing the plate to the soil and constantly increasing, and based on the value of the shear load whereat the plate is shifted relative to the soil, the value of specific resistance of the frozen soil on the side surface of the foundation is estimated. The frozen soil is extracted from the core when drilling a borehole for the pile, the core is sawed in half in the plane of the diameter and each half thereof is enclosed in a metal cage. The soil is pressed to the plate from both sides using screws with pressure cells at the end with force. The increasing shear load is applied stepwise via an elastic element, each step of the relaxing shear load is maintained until stabilisation thereof, after the stabilised value of the relaxing subsequent load step is equal to the previous one, the absolute value of negative temperature of the soil is reduced and the new stabilised value of the relaxing shear load is fixed at this temperature, then the last operation is repeated until the soil is fully thawed, and based on the values of the stabilised value of the relaxing tangential load at different values of the temperature, the value of specific resistance forces on the side surface of the pile foundation at different values of negative temperatures is estimated.

EFFECT: provided increase in the accuracy of determining the bearing capacity of a pile in frozen soils and increase in the accuracy and informative value of testing, thereby providing a possibility of predicting a change in the bearing capacity of the pile in the event of a change in the temperature field of the mass and in case of thawing thereof.

4 cl, 1 dwg