Cast-in-place pile integrity detection device and method based on densely distributed fiber grating temperature sensing technology

Abstract

The invention discloses a cast-in-place pile integrity detection device and method based on a densely distributed fiber grating temperature sensing technology. A metal material with a large thermal expansion coefficient is adopted as a temperature sensitization element, the temperature sensitization element is annularly pasted to the position, without a protective layer, of an optical fiber, and the optical fiber is bound to a main rib of a reinforcement cage in a fixed-point manner; after the reinforcement cage is put down, the optical fiber is connected with a densely distributed temperature demodulator; concrete starts to be poured, and the mass and the use amount of the concrete are recorded; the monitoring time of the temperature of a pile body is determined according to the use amount and the mass of the concrete; after pouring of the concrete of the pile body is completed, the densely distributed temperature demodulator immediately starts to collect temperature data; and the difference of hydration heat of the concrete along the pile body is obtained according to the collected temperature data, whether concrete pouring is uniform or not and the pile diameter range are judged, and the integrity of a cast-in-place pile is further obtained. By means of the cast-in-place pile integrity detection device and method, the temperature measuring precision and the positioning precision are greatly improved, active heating is not needed, and pile foundation defects can be found as soon as possible and repaired in time.

Description

technical field [0001] The invention discloses a device and method for detecting the integrity of cast-in-situ piles based on densely distributed optical fiber grating temperature sensing technology, and relates to the technical field of quality detection of cast-in-situ piles. Background technique [0002] Cast-in-situ piles have large bearing capacity and strong adaptability, and are widely used in most high-rise buildings, bridges and other projects in my country. With the rapid development of infrastructure projects, the demand for cast-in-situ piles will inevitably develop in the direction of larger and deeper. However, affected by factors such as the uncertainty of geological conditions and the complexity of the construction process, the possibility of integrity defects (defects such as broken piles, diameter shrinkage, segregation, and mud inclusions) will appear during the formation of cast-in-situ piles. As high as 15% to 20%. Due to the large depth and high conce...

AI Technical Summary

Problems solved by technology

However, the existing traditional temperature measurement methods need to deploy a large number of temperature sensors, which increases the cost of pile foundation detection and cannot guarantee the survival rate of the sensors; while the existing thermal method based on distributed optical fiber temperature measurement technology (DTS) The body integrity detection technology is limited by the spatial resolution and temperature measurement accuracy of the distributed optical fiber temperature measurement technology (DTS), and the detection accuracy for small-scale defects is low, especially for low-quality concrete and short pile lengths. Pouring pile detection accuracy is low

Another method is the pile body integrity detection technology based on the active heating distributed optical fiber temperature measurement technology (DTS), which also judges the integrity of the pile foundation based on the heat conduction characteristics of the pile body, but this method requires Sensing optical fiber heating in cast-in-situ piles is used to detect pile foundation defects, which is complicated to operate and prolongs the time of pile foundation detection

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