METHOD TO TEST SOIL BASE WITH PUNCH Russian patent published in 2015 - IPC E02D1/00 

FIELD: construction.

SUBSTANCE: method to test a soil base with a punch includes soil loading in a massif with pressure at the punch foot to the final pressure and maintenance at continuous final pressure to stabilise punch subsidence, to record punch subsidence during loading and final pressure, and determination of characteristics of deformability of the soil base. Soil is submerged by pressure rising with permanent speed, and punch subsidence is recorded with a pitch of not more than 0.005 mm, at the same time in process of soil loading they calculate speed of punch subsidence at each step of punch subsidence recording according to the given dependence. Cycles of variation of punch subsidence speed are identified from the first one (n₀), where irregularities of the soil base under the punch foot are smashed, to the last one (n_k), where the last cycle of punch subsidence speed variation was completed, they determine the maximum value of punch subsidence speed (f_max.i, m/kPa) in each cycle of punch subsidence speed variation and average value of punch subsidence speed (avg f_max.i, m/kPa) for all cycles of variation of punch subsidence speed from n₀ to n_k and value of variation coefficient. Upon completion of each new (n_k+1) cycle of variation of punch subsidence speed they calculate the average value of punch subsidence speed for all cycles of variation of punch subsidence speed from n₀ to n_k+1 and the variation coefficient value. They build a row of average values of punch subsidence speed (f_max.i, m/kPa) for all cycles of punch subsidence speed variation from n_k+1 to n₀ and their appropriate values of variation coefficient, after the variation coefficient, as pressure rises at the punch foot, takes the minimum value, soil loading continues to the moment, when speed of punch subsidence becomes equal to the limit speed of soil base subsidence for this structure, following the results of testing, they calculate the module of soil deformation according to the given dependence, they determine the rated resistance of the soil base as the value of the final pressure and characteristics of soil creep by approximation of the curve of punch subsidence on time at p_fin=const according to the given dependence of the function.

EFFECT: determination of a deformation module, value of rated resistance and characteristics of soil base creep under conditions modelling soil base loading during real construction of the structure, increased validity of testing results and reliability of forecast of soil base deformation in a foundation during one test.

4 dwg