Technology for performing foundation pile quality detection and geology survey by adopting single tube longitudinal wave method

Abstract

The invention relates to a technology for performing foundation pile quality detection and geology survey by adopting a single tube longitudinal wave method. The technology is relevant to comprehensive testing of the actual using effect of a foundation pile and is characterized in that longitudinal wave transmitting downwards along a pile body is generated by knocking the top surface of the foundation pile, the longitudinal wave velocity and pile length of the foundation pile can be accurately measured by detecting the time difference of arrival of the longitudinal wave in a sounding pipe, and the quality of pile body concrete can be judged; actual measurement on the time difference of arrival of the longitudinal wave which is transmitted from the pile side soil along the knocked pile body can be conducted in adjacent pipelines or geological bore holes, and the length of the foundation pile, the pile body quality and the chambering degree can be measured; and the wave length of a geological soil layer can be measured, the condition of the geological soil layer around the pile can be judged, and the rock-inlet condition of the foundation pile can be analyzed. By means of the technology for performing foundation pile quality detection and geology survey by adopting the single tube longitudinal wave method, a signal processor can be configured externally or inserted in on the basis of the existing low-strain ultrasonic detection devices and the like, the technology can achieve foundation pile quality nondestructive testing and geology survey, is an economic and ready-made pile foundation nondestructive testing auxiliary validation method and can remarkably improve accuracy and service level of pile foundation quality decision.

Description

Technical field [0001] The invention relates to the technology of foundation pile construction quality non-destructive testing and geological detection. Background technique [0002] Under the existing technical conditions of pile foundation dynamic measurement, there are still many uncertainties in the detection of pile foundation construction quality, which affect the correct judgment of pile foundation construction quality: [0003] 1. Although the pile dynamic measurement method can sense the information of the soil around the pile and the rock formation at the bottom of the pile, it cannot confirm the bearing capacity of the pile foundation because it cannot quantify the specific indicators corresponding to its geological conditions. [0004] 2. The wave velocity of the foundation pile cannot be accurately measured, so that the pile length cannot be accurately determined and the overall level of the concrete quality of the foundation pile cannot be evaluated. There are...

AI Technical Summary

Problems solved by technology

[0002] Under the existing technical conditions of pile foundation dynamic measurement, there are still many uncertainties in the detection of pile foundation construction quality, which affect the correct judgment of pile foundation construction quality:

[0003] 1. Although the pile dynamic measurement method can sense the information of the soil around the pile and the rock formation at the bottom of the pile, it cannot confirm the bearing capacity of the pile foundation because it cannot quantify the specific indicators corresponding to its geological conditions.

[0004] 2. The wave velocity of the foundation pile cannot be accurately measured, so that the pile length cannot be accurately determined and the overall level of the foundation pile concrete quality cannot be evaluated

There are still some application difficulties in the method of using dual sensors to calibrate the wave velocity of foundation pile concrete at the pile head, such as: (1). The situation of exposed pile head rarely exists; (2). Relatively poor, cannot represent the average quality of the whole pile, etc.

[0005] 3. Cast-in-place piles with variable pile sections and large variations, as well as geological conditions with obvious changes in the soft and hard soil layers around the piles, will lead to inaccurate test results, and other auxiliary methods need to be used for verification

[0006] 4. For the quality inspection of super-long piles, artificially dug-in-place piles, and multi-segment prefabricated driven piles, etc., it is often impossible to detect the reflection signal at the bottom of the pile, so it can only rely on the comprehensive judgment of the inspection personnel combined with experience, or use other methods. Method for further testing

[0008] The existing detection technology of pile foundation ultrasonic transmission method has its limitations, and there are situations such as the inability to implement effective detection and false detection and re-judgment:

[0009] 1. The pile foundation ultrasonic transmission method can only reflect the concrete quality of the pile body within the scope of the acoustic measuring tube, but cannot reflect the soil around the pile and the bearing layer at the pile tip

[0010] 2. Since the buried acoustic tube is prone to displacement, distance measurement becomes an important parameter of uncertainty, so it is difficult to obtain an accurate average wave velocity that can represent the construction quality level of the whole pile; complete deviations from the physical meaning often occur at the bottom of the pile The maximum or minimum value of , making it difficult to judge

[0011] 3. When small defects such as local mud inclusions appear around the acoustic tube, it is easy to be misjudged as major quality problems such as serious diameter shrinkage and broken piles

[0012] 4. When the inner wall of the acoustic measuring tube is corroded, the outer wall is thicker in mud, or the acoustic measuring tube is separated from the concrete and cracked, the ultrasonic wave cannot be transmitted. These situations may lead to mismeasurement and misjudgment

[0013] 5. When the acoustic measuring tube is deformed or blocked, the pile body or pile bottom cannot be effectively detected and judged, and core pulling is required

[0014] Under the existing technical conditions of non-destructive testing of pile foundation construction quality, when it is impossible to detect and judge or there are quality doubts, the core-pulling method is generally used for verification, but the cost of core-pulling method for pile inspection is high and time-consuming. For long piles It is also difficult to pull the core to the bottom of the pile. At the same time, it can only provide the bearing layer at the pile end, and cannot fully analyze the bearing capacity of the pile foundation. Therefore, the existing pile foundation construction quality inspection technology cannot fully meet the actual needs.

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