Study On Design Method For Tunnel Support Structure Based On Surrounding Rock Deformation

As center of the infrastructure construction like railway and highway shifts to the west, the number and scale of tunnels have developed rapidly. However the difficulties of tunnel construction increase because of the geological complexity of western mountain areas.To determinate the value and distribution pattern of surrounding rock pressure and supporting load is the key to designing tunnel supporting structures. Thus, research have been done mainly on the surrounding rock pressure and supporting load.Relaying on capacity-expansion reconstruction of Jinhua-Wenzhou Line, through investigation, statistical analysis, numerical simulation and field measurement, determination methods of surrounding rock pressure of deep-buried tunnel were studied and results were obtained as follows:1) Through statistical analysis of the existing field data of 174 monitoring sections in 54 tunnels, the overall distribution of surrounding rock pressure in different surrounding rock grade was got, and the relationship between surrounding rock pressure and surrounding rock grade were analyzed, so were the relationship between surrounding rock pressure and span of tunnel. Formula of surrounding rock load of deep-buried tunnel calculated in accordance in Code for Design on Tunnel of Railway was modified.2) Relying on capacity-expansion reconstruction of Jinhua-Wenzhou Line, combined with field-measured surrounding rock pressure, through comparative analysis of common calculation method of surrounding rock pressure, suitable calculation method of surrounding rock pressure for tunnel of Jinhua-Wenzhou Line were selected. Through statistical analysis of field-measured vertical and horizontal surrounding rock pressure and numerical analysis, suitable load distribution pattern for Jinhua-Wenzhou Line railway tunnel were recommended. Surrounding rock pressure calculation method of Jinhua-Wenzhou Line railway tunnel were put forward.3) Combined with field-measured data and numerical analysis, based on safety design principles, suitable displacement load distribution pattern for Jinhua-Wenzhou Line railway tunnel were recommended. Calculation method of tunnel structure internal force based on surrounding rock displacement were put forward.4) The supporting load of Jinhua-Wenzhou railway tunnel is determined by using the characteristics curve method.