Mechanical effects of advanced supporting on controlling deformation of surrounding rock of tunnel

Research purposes: With the three-dimensional elasto-plastic finite element method, the design parameters of the advanced supporting and the roof supporting for the excavation surface of the tunnel were analyzed, the effects of the different excavation methods and the different lengths of bench and core soil on the ground settlement, the mechanical behaviors of pipe roof supporting and stability of the excavation surface under conditions of having roof supporting and having no roof supporting were studied and the regular knowledges were summarized for providing the reference to the selection of the excavation method of tunnel under the complex geological condition and the design of the roof supporting. Research conclusions: (1) Remaining the core soil can significantly improve the excavation fsurace stability and the optimal length of core soil is in D/3 ~ 2D/3 range. In the process of construction, the length of the core soil should be equal to the bench length. (2) The core soil plays a little role in controlling the horizontal displacement of surrounding rock. In weak stratum, the horizontal displacement can be controlled by using the core soil along with taking the measures of roof supporting like the pipe roof reinforcement, rather than only by using the core soil.