Ballastless track board disengaging nondestructive detection method based on elastic waves

Abstract

The invention discloses a ballastless track board disengaging nondestructive detection method based on elastic waves. By means of confirming a function relationship between shock excitation elastic wave frequency and disengaging surface elastic wave reflectance, a function relationship between the shock excitation elastic wave frequency and packing layer elastic wave reflectance is confirmed, the shock excitation elastic wave frequency which can make the ratio of the disengaging surface elastic wave reflectance to the packing layer elastic wave reflectance obtain the maximum value is found, shock excitation elastic wave with the frequency is directly stimulated, so that a disengaging surface reflected signal is in a state easiest to identify, and the disengaging judgment accuracy of a ballastless track board is greatly improved. On the basis, a judging standard whether the disengaging exits is provided at the same time. The invention further discloses a ballastless track board disengaging rate detection method based on the elastic waves.

Description

technical field [0001] The invention relates to the technical field of safety detection, in particular to a method for detecting empty space of a ballastless track slab. Background technique [0002] The ballastless track cancels the sleeper and ballast bed of the traditional ballast track, and uses the prefabricated reinforced concrete slab to directly support the rail, and fills the CA mortar or self-compacting concrete cushion between the top plate and the base, which is a new fully supported slab type track structure. It has the following advantages: good stability and smoothness; low building height and light weight, which can reduce the second phase load of bridges and reduce tunnel clearance; slow track deformation and good durability; no maintenance or less maintenance and low maintenance costs, etc. advantage. Ballastless track has very high requirements on engineering materials and basic civil engineering, so the initial construction cost is higher than that of b...

AI Technical Summary

Problems solved by technology

[0023] (1) During the test, it is necessary to couple the probe with the measured surface with a coupling agent such as butter, and the test efficiency is low

[0024] (2) The excitation signal has low energy and high signal frequency (generally above hundreds of KHz), which decays quickly in the track plate and the detection depth is shallow

[0026] (4) The linearity of the spectral response curve of the probe is poor, and it is difficult to perform frequency domain analysis

However, since the acoustic impedance of the filling layer (CA mortar or self-compacting concrete) is lower than that of the track slab, the excited shock elastic wave will also be reflected when it encounters the filling layer.

The reflection signal of the filling layer and the reflection signal of the hollow surface are mixed together, which brings great difficulties to the identification of the reflection of the hollow surface

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