Concrete shallow-surface-layer ultrasonic surface wave detection method based on arrangement type ultrasonic seismic focus

Abstract

The invention discloses a concrete shallow-surface-layer ultrasonic surface wave detection method based on an arrangement type ultrasonic seismic focus. The concrete shallow-surface-layer ultrasonic surface wave detection method is implemented by a seismic focus device and a receiving device and comprises three stages of data acquisition, data processing and shallow surface layer shear wave velocity calculation; in the data acquisition stage, before data acquisition is started, firstly, a detection region needs to be determined, region meshing is carried out on a to-be-detected surface according to a detection level resolution demand, and all scanning point positions are determined, then scanning is sequentially carried out on each point position, and the process is repeated until scanningon all the point positions is finished; the data processing comprises signal coherence analysis, phase extraction and average surface wave velocity calculation; and according to a data processing result, shallow surface layer shear wave velocity calculation is carried out so as to judge whether a shallow surface layer below the detection region has defects. According to the invention, a surface wave phase velocity is extracted by phase analysis and an average shear wave velocity of a shallow surface layer of concrete is estimated hereby; and on the basis of a corresponding relationship between the shear wave velocity and medium hardness, a defect region of the shallow surface layer of the concrete is detected and identified.

Description

technical field [0001] The invention relates to an ultrasonic surface wave detection method of concrete shallow surface layer based on arrayed ultrasonic vibration sources. Background technique [0002] With the continuous and stable development of my country's economy, the country is increasingly strengthening infrastructure construction. High-speed (passenger dedicated line) / heavy-haul railways and expressways are the main directions for the development of railways, roads and land transportation respectively. The level of new railways and road tunnels , scale and quantity are increasing year by year. In tunnel engineering, concrete is one of the main structural materials of buildings. Concrete is a multiphase composite system, and the phases are randomly intertwined to form an extremely complex internal structure. The damage of concrete is inevitable, including physical Processes, such as freeze-thaw cycles, fire, water erosion, and chemical processes, such as carbonizatio...

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Problems solved by technology

[0005] The conventional detection method drag chain method has two shortcomings. On the one hand, it is severely restricted by the external environment and cannot detect reinforced concrete structures with asphalt coverings; The area to be tested; strict traffic control is required during detection, and no traffic noise is allowed; on the other hand, due to the size of the chain itself and the limitation of acoustic feedback sensitivity, the accuracy is relatively low and can only reach the meter level, and the judgment standard is too subjective. Determined by technicians based on experience, resulting in poor stability of results

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