Method for analyzing bearing capacity of foundation pile by joint inversion of multiple hammering signals

Abstract

The invention relates to a method for analyzing the bearing capacity of a foundation pile by joint inversion of multiple hammering signals. The method for analyzing the bearing capacity of the foundation pile by the joint inversion of the multiple hammering signals comprises the steps that a heavy hammer is lifted from low to high to different heights, strain and acceleration response signals produced by different times of hammer impact are recorded by strain rings and accelerometers on the two symmetric sides under a pile tip, and the measured impact force and the measured particle velocity of different times of hammering are obtained from the measured signals of the positions of measure points; the particle velocity theoretical values of the corresponding hammering times are calculated from the measured forces of different times of hammering and the preset parameters of a pile-soil interaction model; the objective function related to pile-soil parameters is established by the difference value between the measured and theoretical calculating values of the particle velocity of different times of hammering; and model parameters are adjusted, and when the difference value of the previous and subsequent step objective function is less than the preset error, the calculation value of the ultimate bearing capacity and other parameters of the pile-soil interaction model are obtained.According to the method for analyzing the bearing capacity of the foundation pile by the joint inversion of the multiple hammering signals, hammer tests at different heights of the foundation pile arecarried out, the amount of data for inversion analysis is increased, the sensitivity of the optimized objective function to the variation of pile-soil interaction parameters is improved, and the uncertainty of solution in the inversion analysis is reduced.

Description

technical field [0001] The invention relates to the field of foundation foundations, in particular to testing and analysis of foundation single pile bearing capacity, and is applicable to road bridges, civil and industrial buildings, docks, power plants and other single pile foundation projects. Background technique [0002] The ultimate bearing capacity test of foundation piles is very important to the safety of foundation engineering. Commonly used tests include load method, heap load method and self-balancing method. Although these methods have intuitive results and high precision, they are time-consuming, costly and complicated to operate. The high-strain dynamic measurement method is a method for testing the bearing capacity of foundation piles developed in the 1960s. However, the uniqueness and accuracy of the solution of this method are affected by the following factors. (1) Test factors: the uneven force on the pile top section caused by the position deviation of th...

AI Technical Summary

Problems solved by technology

However, the geometric parameters of the actual pile length are different, and the weight and height of the drop hammer are also different. It is difficult to divide the time intervals of pile-soil interaction loading, sliding, and unloading. In addition, the signal-to-noise ratio of the follow-up reflected wave response at the bottom of the pile is low, which is not conducive to increasing the analysis time period. length

The above analysis shows that in the high-strain dynamic test of foundation pile bearing capacity, it is difficult to make a final decision, and the calculation results are uncertain, which affects the popularization and application of dynamic test piles in actual engineering.

Images