Tubular pile static bearing capacity testing method and system based on traveling wave tracing principle

Abstract

The invention discloses a tubular pile static bearing capacity testing method and system based on the traveling wave tracing principle, and the method comprises the steps: arranging sensors on the inner wall of a tubular pile in the axial direction of a pile body, and arranging various types of sensors on the pile body in a one-to-one correspondence manner in a ring shape; hammering the pile top of the tubular pile, and synchronously collecting and recording force wave signals and velocity wave signals of each measuring point of the pile body along the axial direction of the pile body; force waves propagating in the axial direction of the pile body are decomposed into upward waves and downward waves through a traveling wave decomposition method, and pile body traveling wave tracing is achieved; calculating to obtain a dynamic resistance time history curve and a pile end soil dynamic resistance time history curve of each pile section, and determining pile side soil dynamic resistance and pile end soil dynamic resistance; and determining the maximum static bearing capacity of the tubular pile and the ultimate bearing capacity of the pile. According to the method, the static bearing capacity of the pile is directly evaluated through the actually measured pile body dynamic signal, the calculation process does not involve specific parameters of soil around the pile and human factors, and the influence of the property complexity of the soil around the pile and the subjectivity of testers on the bearing capacity evaluation result is effectively avoided.

Description

technical field [0001] The invention belongs to the technical field of pile foundation engineering detection, in particular to a method and system for testing the static bearing capacity of pipe piles based on the principle of traveling wave tracing, which is suitable for evaluating the bearing capacity of pile foundations. Background technique [0002] In recent years, with the rapid development of my country's engineering construction, pile foundations have been widely used in various infrastructure projects such as construction, transportation, water conservancy and municipal administration. Whether the bearing capacity of the pile foundation meets the design requirements is very important to the safe service of the superstructure, so the effective test of the bearing capacity of the pile foundation is an indispensable part of engineering inspection and has extremely important engineering practical significance. [0003] The existing test methods of pile foundation bearin...

AI Technical Summary

Problems solved by technology

Both of these two pile foundation bearing capacity dynamic measurement methods are to install a group of acceleration and strain sensors symmetrically near the top of the pile, and calculate the limit of the pile foundation by testing the velocity and stress wave signals at the top of the pile under the hammer load. Bearing capacity, although the CASE method has a relatively mature theoretical system, it makes many rough assumptions about the pile-soil system, which greatly limits its application range and working conditions, especially for piles with good support conditions at the pile end. The test results deviate greatly from the actual ones; the waveform fitting method selects one of the actual measured pile top velocity and stress signals as the input signal, substitutes it into the pre-built pile-soil theoretical model, and inverts it with the help of the huge computing power of modern computers. The output signal, by changing the parameters of the theoretical model, repeatedly compares the measured output signal and the theoretical inversion output signal until a better fitting effect is achieved, and then calculates the pile foundation using the inversion of the pile-soil system parameter values Static bearing capacity

It can be seen from its principle that the accuracy of its prediction results is greatly affected by the theoretical model of the pre-built pile-soil system. If the pre-built theoretical model is relatively rough, it cannot reflect the actual state of pile-soil interaction, which will lead to a relatively large degree of deviation in the test results. However, choosing a complex theoretical model that is closer to reality will lead to too many parameters to be determined, too much inversion calculation, and poor inversion effect, mainly reflected in the fact that there may be multiple parameter combinations that can achieve the same Waveform fitting effect, which leads to non-uniqueness of test results

In addition, whether it is the CASE method or the waveform fitting method, there is a problem of empirical judgment of the parameters, which leads to the test results being greatly affected by the subjectivity of the testers.

The limitations of the test theory itself and the subjectivity of the testers make the test results of the high strain method less stable and lack engineering convincing

[0004] It can be seen that there are still many problems in the existing test methods for pile foundation bearing capacity, and it is difficult to meet the actual needs of engineering development. Especially for large-diameter pipe piles at sea, traditional test methods are often difficult to obtain good test results. A new method of testing the bearing capacity of pile foundations to improve the pain points of the existing technology, realize the rapid and effective testing of the bearing characteristics of pipe piles, and further promote the development of offshore engineering and marine resources development

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