Study on Prediction Method of Infrasound Waves for Concrete Structure Destruction in Underground Space

Abstract

To study the characteristics of infrasonic wave response during the failure process of concrete samples and analyze the feasibility of infrasonic wave prediction for the failure of concrete structures in underground spaces, rock mechanics loading devices and infrasonic wave acquisition devices were used to carry out infrasonic wave test experiments on concrete samples during uniaxial loading. With the help of MATLAB numerical simulation software, the test results are processed and analyzed by constructing band-pass filtering program, wavelet denoising program and time–frequency analysis program. The analysis results show that: there is infrasound wave during the loading process of the concrete sample; During the loading process, the change of infrasonic wave presents stage characteristics, which can be divided into three stages: the initial stage when a certain amount of infrasonic events occur, the middle stage when there are few infrasonic events and the later stage when infrasonic events increase rapidly and reach a peak. These stages respectively correspond to the compaction deformation stage, elastic deformation stage, plastic deformation and later stage of concrete sample deformation, and there is a good corresponding relationship between them. When the concrete sample is damaged by the peak value, the frequency and amplitude of the infrasound wave have abnormal changes. Therefore, in the early stage of the failure of the concrete structure, when the local failure occurs, there is also an abnormal response of infrasonic wave and the failure of the concrete structure can be predicted based on the abnormal change. At the same time, the infrasound wave, as a kind of low-frequency wave, has the advantages of long propagation distance, small attenuation and flexible position arrangement and has stronger adaptability to the complex underground space environment. It is of great significance to improve the accuracy of underground space concrete structure failure prediction.