Study On The Stability Of Weak Surrounding Rock In Du Jia Shan Tunnel

With the implementation of the western development strategy, the expressway construction has the mountains from plain region in advance, the highway tunnel have been developing rapidly. Tunnel project is oftenkey to highway construction,the cycle and quality of which will directly affect the whole highways construction. in the mountain zones, it is inevitable for tunnels to penetrate rock layers of complex geological conditions, bringing a lot of construction geological hazards.Deformation of Soft rock is one of the common kind, once the cause engineering accident, not only would seriously affect the security of the tunnel construction, and will cause serious economic loss. Therefore,the study of the tunnel deformation mechanism and the support stability,which has great practical significanc in the rapid construction safety after tunnel.Based on the expressway of Du Jiashan tunnel construction as an example, the use of geological survey, the theory analysis and numerical simulation methods tunnel large deformation are analyzed and summarized, and put forward the reasonable measures to support stability of surrounding rock, get the main achievements are as follows:(1) Through of research in geological characteristics and engineering properties, analysis of the deformation of the surrounding rock for imported large causes of Du Jiashan tunnel. According to the actual situation Du Jiashan tunnel excavation, this happens large deformation and surrounding rock tunnel excavation and supporting of strength, way and construction method of groundwater measures, such as the relationship between the factors. (2) According to the particularity of the tunnel, through strong earthquake zone in tunnel engineering after carry out especially in thousands pieces as a representative of the Du Jiashan rock tunnel testing set, compared with the original design optimization, not only solved the Du Jiashan excavating tunnel encountered the deformation of the disaster, with the smooth construction of the tunnel that obstacle, for wide Kennedy expressway smooth transfixion all lay the foundation of similar type of tunnel construction has important realistic meaning and value of popularization.(3) Using ANSYS software of tunnel excavation process in numerical simulation analysis. Through the comparison of the excavation, whole section reserved core soil plus two steps excavation, three steps excavation this three kinds of methods, the results show that the the three methods to reduce the deformation of the tunnel excavation in turn. The three steps the testing method of reserve core soil, reduce in supporting system for surrounding rock in the load proportion, and narrowed the scope of plastic zone, which can effectively restrain the deformation caused by tunnel excavation.