Pile foundation length testing method based on thermal response

Abstract

The invention discloses a pile foundation length testing method based on thermal response. According to the method, a heat source hole, a first temperature measurement hole and a second temperature measurement hole are drilled in the two sides of a pile to be tested and in a position of the periphery of the pile, the distances between the heat source hole and the two temperature measurement holes are equal, and the heat source hole is provided with a heat source (heat transfer pipe) to be used for measuring the temperatures of different depths of each temperature measurement hole and conducting contrastive analysis of the position of the bottom of the pile. The different thermophysical properties of a pile material and oil around the pile are utilized, temperatures are different after heat reaches the same position after passing through different media, and the length of the area where a pile body is located can be analyzed according to the difference. Due to the adoption of pile side drilling, the problems that the work amount is large in the traditional in-situ digging process, the structure of the pile body can be damaged by borehole coring, and only short piles can be tested due to low strain are solved; furthermore, pile head digging is not needed, damage to the pile body is avoided, and nondestructive testing is achieved; the method is suitable for testing piles in various depths with various diameters, and cost is low.

Description

technical field [0001] The invention relates to a thermal response-based pile length detection method, especially a quantitative description method for concrete damage evolution law under repeated impact, which is mainly applicable to the detection field of building pile foundation and pile foundation engineering, and belongs to pile foundation detection technology field. Background technique [0002] As a traditional form of foundation, pile foundation has a long history of development. Since pile foundation is a concealed project, its quality cannot be detected through observation and direct measurement. There are many disadvantages in its construction that will cause quality problems in the pile body, including : Broken piles, necking, mud, segregation, short piles and other phenomena. In particular, phenomena such as broken piles and short piles have a direct impact on the bearing capacity of foundation piles or the ability to resist lateral impact, and even affect the ...

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Problems solved by technology

[0003] Before the present invention, the Chinese invention patent "A Method for Detecting Pile Length by Ultrasonic Side Hole Detection" (Patent No.: CN101929167A) disclosed a method for detecting pile length by ultrasonic side hole detection. The difference in dielectric impedance is large, and during the transmission of ultrasonic waves, there will be reflections of abrupt impedance changes at the pile-soil interface; compared with the traditional method, this invention does not require excavation and is applicable to pile foundations of different lengths, but this method also has shortcomings: When drilling on one side of the pile, you can only test the ultrasonic reflection of the pile-soil contact surface in a small area on this side. If there is a problem with the quality of the pile, a narrow and long pile-forming area will be formed on one side of a certain position, and other areas at the same level will be tested. If the pile is not completed, there will be a large error in the test result; the reflection of ultrasonic waves at the pile-soil interface is the result of different impedances. When there are media such as sand and gravel in the soil, it will cause interference to the launch, resulting in inaccurate test results.

The low-strain wave launch method can only be applied to short-length test piles and steel pipe piles, and the pile head needs to be excavated to be tested at the pile head; It is inconvenient to select detection piles for inspection in the actual completed project, and it cannot be applied if the pile length is detected for the existing expressway; the drilling core method is suitable for cast-in-situ piles, and it is prone to the situation that the drilled hole deviates from the pile, and the The method will cause damage to the pile, which belongs to destructive testing; while the field excavation method has high accuracy, but it needs to be excavated to the depth of the pile, which requires a large economic cost

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