Patent RU-2750919-C1 (RU)
Title: Method for testing ground foundation with pile
Inventor: LYASHENKO PAVEL ALEKSEEVICH
IPC: E02D1/00
Filed: 2020-10-26
Granted: 2021-07-06
Abstract: FIELD: construction. 
     SUBSTANCE: invention relates to construction, namely to methods for testing piles with static load. The method for testing the ground foundation with a pile includes the application of a pressing force continuously increasing at a constant speed to the model pile, synchronous registration of the pressing force, the time of its application and the pile sediment with a step of 0.005 mm of the pile sediment. As a model pile, a natural bored pile is used in the foundation of the structure. At the lower end of the model pile, a ground pressure sensor is placed. On the side surface of the model pile, meters of vertical ground deformation relatively to the side surface of the pile are placed. At the levels of the meters, depth marks are placed along a closed contour in the plan with a radius of 1-2 of the pile diameter from the pile axis in the directions from the axis of the model pile to neighboring working piles in this pile foundation. Vertical ground deformation relatively to the side surface of the pile, vertical movements of depth marks, ground pressure under the lower end of the pile, which is synchronous to registering pile sediment with a step of 0.005 mm of pile sediment, are additionally registered. After reaching the final value of the indentation force at its constant value, until the model pile sediment is stabilized according to the condition of 0.005 mm/h, the pile sediment, the time of its registration, the vertical ground deformations relatively to the side surface of the pile and the vertical movements of the depth marks at all levels of their placement and the ground pressure under the lower end of the pile, which is synchronous to the pile sediment with a step of 0.005 mm of the pile sediment, are synchronously recorded. According to the measurement data, the cycles of changes in the pile sedimentation rate are distinguished. The values of vertical ground deformations relatively to the side surface of the pile and vertical movements of the depth marks are distinguished, which are synchronous to the bursts of the pile sedimentation rate. The lengths of the projections of the traces of shear and separation cracks on the horizontal plane are calculated and taken as the horizontal dimensions of the pile base. Additionally, the position of the beginning of the shear and ground separation crack is determined. The directions of the greatest slopes of the surfaces of the depth marks movement are determined. Based on the obtained data, the increments of elastic and plastic deformation of the ground base are calculated in each cycle of changes in the sedimentation rate of the model pile. The increments of the resistance of the ground base to the immersion of the working pile and the corresponding increments of elastic and plastic deformations of the ground base in the entire range of the pressing force are determined. The load-bearing capacity of the working pile is determined by the condition of limiting its precipitation. The increments of the vertical and horizontal components of the elastic reaction of the ground base for the working pile are calculated at distances equal to the horizontal dimensions of the base.  
     EFFECT: increasing reliability and accuracy of determining the load-bearing capacity of the working pile in the foundation of the structure, the resistance of the ground base to the immersion of the pile, determining the size of the ground base of the pile at different levels along the length of the pile and the forces exerting influence from the tested pile to neighboring piles in this pile foundation. 
     1 cl, 3 dwg