Existing building foundation pile quality detecting method and device

Abstract

The invention discloses an existing building foundation pile quality detecting method. The existing building foundation pile quality detecting method comprises the steps that an excitation hole filledwith water in a cushion cap is used as a discharge space of a pulse discharge electrode, pulse discharge is performed, and the excitation force generated by the discharge does not need to pass through the cushion cap and is directly transferred to a lower pile body of a foundation pile through a water medium, and then a reflected wave pressure waveform collected by a hydrophone in the excitationhole and a reflected wave vibration waveform collected by an acceleration sensor in a waterless collection hole are used for determining whether defects exist in the pile body or not and determining the specific location, type and size of the defects through time-domain and frequency-domain analysis of the reflected wave pressure waveform and the reflected wave vibration waveform; and the hole bottoms of the excitation hole and the collection hole are the top of the foundation pile to avoid the situation that attenuation of longitudinal wave energy is excessive due to the fact that the cushioncap is too thick. The invention further discloses a detection device applying the existing building foundation pile quality detecting method. The detection method and device can accurately judge thequality of the foundation pile and have the advantages of high efficiency and low cost.

Description

technical field [0001] The invention relates to the field of non-destructive detection of building foundation piles, in particular to a quality detection method and device for existing building foundation piles. Background technique [0002] Existing building foundation piles are used as the bearing foundation of the building, and their quality will directly determine the safety and durability of the superstructure; For bridges impacted by water, ships and floods, the quality inspection of foundation piles of houses and bridges will become very important; in addition, for the phenomena of tilting, deformation, settlement and cracking of superstructures caused by foundation problems or construction quality problems, It is necessary to carry out quality inspection on the foundation piles of the corresponding buildings; when repairing and strengthening old buildings, adding loads and adding floors, it is necessary to understand the integrity and bearing capacity of the original...

AI Technical Summary

Problems solved by technology

[0003] Different from newly-built foundation piles with free pile ends, the upper pile ends of existing building foundation piles are very hidden, the detection environment is complex, and the detection results are greatly hindered and interfered by the cap platform and the upper building structure. Currently, the commonly used method in foundation pile detection , such as the core drilling method, static load test method, traditional high-low strain method, etc. are not applicable, while the acoustic wave transmission method is obviously not suitable for the foundation pile detection of existing buildings because it needs to arrange acoustic tubes in the pile in advance; For foundation pile detection, the traditional low-strain reflection method is a relatively reliable foundation pile integrity detection method. It is difficult to directly contact with the pile end due to the obstruction of the building structure, and this method cannot know the bearing capacity of the foundation pile; the traditional hydroelectric effect method places a bucket device at the pile end, and places a high-voltage discharge electrode in the bucket device. The high-voltage pulse discharge generates a pressure pulse to excite the top of the foundation pile, and then the pressure sensor placed in the barrel receives the dynamic response of the pile-soil system under the action of the pressure pulse, and the vibration characteristics of the pile-soil system are analyzed in the time domain and frequency domain respectively. analysis, deduce the nature, size and location of the pile body defects, and calculate the allowable bearing capacity of the foundation pile, but when the hydroelectric effect method detects the foundation pile, the bucket needs to be placed on the top of the foundation pile, which is obviously not suitable for existing building foundations. pile detection

Patent CN85104819 introduces a method for testing the integrity of foundation piles using the hydroelectric effect. This method uses the method of placing a water bucket on the top of the installation to generate an exciting force, and places a speed sensor on the top or side of the pile. It mainly uses self-power The quality of foundation piles can be judged by the spectrum, and the installation method of acquisition equipment is still not suitable for foundation pile detection of existing buildings

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