Abstract
The most common structural defect of a tunnel in the operation period is the cracking of concrete lining. The insufficient thickness of tunnel lining is one of the main reasons for its cracking. This study studied the cracking behavior of standard concrete specimens and the failure behavior of tunnel structures caused by insufficient lining thickness using Cohesive Zone Model (CZM). Firstly, zero-thickness cohesive elements were globally inserted between solid elements of the standard concrete specimen model, and the crack development process of different concrete grades was compared. On this basis, a three-dimensional numerical model of the tunnel in the operation period was established. The mechanism and characteristics of crack propagation under different lining thicknesses were discussed. In addition, the statistics of cracks were made to discuss the development rules of lining cracks quantitatively. The results show that the CZM can reasonably simulate the fracture behavior of concrete. With the increase in concrete strength grade, the number of cohesive damaged elements and crack area increases. The insufficient lining thickness changes the lining stress distribution characteristics, reduces the lining structure’s overall safety, and leads to the cracking of the diseased area more easily. When surrounding rock does not contact the insufficient lining thickness, its influence on the structure is more evident than when surrounding rock fills the entire lining thickness. The number of cohesive damaged elements and the size of the crack area increases significantly.
Highlights
The tunnel was affected by different degrees of damage during operation
Under the action of external force or water pressure, it is easy to cause a series of structural defects such as cracks and the leakage of the concrete lining structure of the tunnel, which seriously affect the safety of the tunnel structure and shorten its service life [5,6]
The feasibility of Cohesive Zone Model (CZM) in ABAQUS, in order to simulate the fracture behavior of concrete, was verified by the simulation of the cracking behavior of standard concrete specimens
Summary
The tunnel was affected by different degrees of damage during operation. The most common structural damage was lining crack damage [1,2,3]. Studied the safety status of tunnel structure with a numerical simulation method due to insufficient lining thickness [14]. The feasibility of CZM in ABAQUS, in order to simulate the fracture behavior of concrete, was verified by the simulation of the cracking behavior of standard concrete specimens On this basis, the cracking mechanism of the concrete lining structure of highway tunnels with insufficient lining thickness was studied. In order to verify the feasibility of CZM to simulate the cracking behavior of concrete structures, a three-dimensional model with the same size as Testing Methods of Cement and Concrete for Highway Engineering was established in ABAQUS.
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