Research On Tunnel Damage Identification Method Based On Wavelet Analysis

Tunnel is an important part of the transport system and the security of the tunnel structure is the premise that the transportation system is the normal operation. In practical engineering applications, because of the tunnel design, construction and natural disasters and so on, many tunnels often cause aging, cracks, damage and other injuries. The tunnel structure may fracture, collapse and other serious consequences, leading to significant loss of lives and property of people. In recent years, wavelet analysis method is a new kind of time-frequency analysis method which is developed in the international. It has the nature of space localization and unique advantage in signal singularity detection.We can use wavelet analysis to study the damage identification problem of the tunnel structure.It not only has great theoretical significance, but also has important application value for engineering.In this paper, using wavelet analysis theory, we research influence the damage on the dynamic characteristics of the tunnel. For the displacement mode, rotation mode and the curvature mode, we establish principle of the tunnel structure damage identification.This article makes the the tunnel which contains injury as research object, establishes tunnel structure,s curved beam element model, uses the finite element method analysis vibration characteristics of the tunnel structure, obtain the displacement mode, rotation mode and curvature mode of the tunnel by calculating. It makes dbN wavelet as mother wavelet and makes continuous wavelet transform on modal parameters using wavelet analysis, simulate the local damage of the tunnel using decreases of cell size.The paper puts forward two-dimensional rigid foundation tunnel model, establish the corresponding damage identification wavelet analysis method of tunnel.We study vibration characteristics of two-dimensional rigid foundation tunnel model and obtain the displacement mode, rotation mode and curvature mode of the tunnel damage model by using finite element analysis method.This paper makes continuous wavelet transformation on modal parameters using dbN wavelet and simulate the local damage of the tunnel using decreases of cell size. The calculations show that mutation positions of modulus maxima of the wavelet coefficients coincide with the section position of damage. It can also verify the effectiveness of the method in this paper.This paper puts forward two-dimensional elastic foundation tunnel model because of considering the impact of the foundation on the tunnel structure, establishes the corresponding damage identification wavelet analysis method of tunnel,study vibration characteristics of tunnel model,then obtain the displacement mode, rotation mode and curvature mode of the tunnel damage model.It makes continuous wavelet transformation on modal parameters using dbN wavelet and simulate the local damage of the tunnel using decreases of cell size. The calculations show that mutation positions of modulus maxima of the wavelet coefficients coincide with the section position of damage and verify the effectiveness of the method in this paper.The paper is based on Sun tunnel of Dongyue-Changde highway in Hunan province. According to collapsing in the excavation process and combing with the practical monitoring data of tunnel construction, it makes damage identification to tunnel using two-dimensional elastic foundation tunnel model, verify effectiveness of tunnel damage identification method based on modal parameter and has certain directive significance to engineering applications of tunnel structural damage detection.