Study On The Failure Mechanism And Control Techniques Of The Voids Behind Tunnel Lining

China railway tunnel construction has been nearly a hundred years of history, road tunnels has developed rapidly in recent decades, due to the limitations of the geological conditions, construction technology, management methods and other factors, many tunnels are varying degrees of all kinds of diseases, the voids behind the lining is a very common disease phenomenon. Some events show that the voids is the main culprit for the tunnel collapse, it gives the construction and operation of tunnel a tremendous security risk. It is an important subject to study the voids’s failure mechanism, influencing factors, as well as coupling effect with other diseases. The main research work as follows:1. This paper analysis the main causes of the voids behind the lining, and summarizes the failure modes of the lining caused by the voids.2. Focus on the arch crown, load-structure method has been used to study the relaxation effect of pressure, layer-structure method has been used to study the void effect, and cracking mechanism of cracks caused by the voids are studied by using XEFM.3. According to the three-dimensional numerical analysis of the voids behind lining, it comes to the conclusion that the crack patterns are determined by the length-width ratio of the voids, the destruction test of the one, two-way slab perfectly explains this feature.4. This paper analysis the influence of different depths, sizes, positions of the voids on the lining structure stress characteristic with considering the lateral pressure coefficient of surrounding rock, surrounding rock, and support form factors.5. The effects of the voids coupling with frost heave, earthquake, cracks and thickness lack on the bearing capacity of the lining are analyzed respectively.6. Connecting with the actual production process, the preventive measures of the voids are provided. According to the distress characteristics, risk classification of the voids is set up, and renovating countermeasures are put forward. According to analysis the failure mechanism, influencing factors, as well as coupling effect with other diseases of the voids behind the lining, this dissertation aims to provide references and enlightenment for the prevention and remedy of the voids.