Low-strain quality detection measuring tool and testing method thereof

Abstract

The invention discloses a low-strain quality detection measuring tool and a test method based on a test die. The measuring tool is arranged on the top of the exposed pipe pile in a sleeved mode when in use, and the measuring tool includes an impact disc and a positioning support, a sensor is arranged on the lower surface of the impact disc and serves as a detection point, the upper surface is provided with a sand layer, and the surface of the sand layer is leveled and is provided with an impact plate; the positioning support comprises a cross-shaped support and a telescopic rod body, a movablevibration excitation hammer body installation support is arranged on the cross-shaped support so as to locate and install a vibration excitation hammer body to perform vibration excitation impact. According to the method, auxiliary measurement is carried out through the measuring tool, and data collection is carried out through quantitative and standardized operation, through the cooperation of the sand layer and the reasonably arranged detection point, the spread of strain in the horizontal plane and the influences of errors between materials can be buffered and counteracted, and then afterthe data is amplified, the accurate measurement data of the tube pile can be obtained.

Description

technical field [0001] The invention belongs to the field of testing the mechanical properties of materials, and relates to a low-strain quality testing tool and a testing method for monitoring the deformation of high-strength prestressed pipe piles. Background technique [0002] The stress wave reflection method is the most widely used method for detecting the integrity of pipe piles in engineering. Its principle is based on the one-dimensional wave equation. The elastic wave propagates downward. If there are structural defects such as pile bottom, broken pile, severe segregation, necking, and neck expansion in the pile body, obvious wave impedance will be generated at the defect section, so that the stress wave propagating downward will be suppressed. Reflected back to the top of the pile, the signals of these reflected waves are received by the sensors on the top of the pile. After these reflected wave signals are amplified, filtered, analyzed and calculated, the reflecti...

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Problems solved by technology

[0003] Since the theoretical basis of the traditional stress wave reflection method is the one-dimensional wave theory based on the assumption of a plane section, the pile is simplified as a one-dimensional rod, and only the propagation of the stress wave along the pile axis is considered, which makes the drop hammer The height inconsistency will lead to differences in the collected signal waves. When performing data analysis, the signal screening has a certain degree of randomness, which is not conducive to further curve analysis and statistics.

At the same time, there is another problem that is not easy to ignore. The propagation of stress wave is a three-dimensional problem, and the high-frequency wave interference on the pile top is serious when using a vibrating hammer on the pile top. Therefore, for pipe piles with a certain diameter, especially large As far as the diameter pipe pile is concerned, it will make it difficult to judge the defects of the pile body: the same inspection pile, the signal curves collected by different people may be inconsistent; different positions on the top of the pile are struck by the vibrating hammer, and different signals may be generated. As a result, even the same operator will have poor reproducibility and untraceable defects due to the different selection of sensor installation and excitation point position, and it is difficult to ensure the consistency of low-strain acquisition signals, resulting in low-strain detection signals The results of judging the integrity of the pile body are different

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