Research On The Influence Of Existing Tunnel By The Blasting Of The Tunnel Near-by And The Assess Of Existing Tunnel's Safety

Since the new tunnel is close to existing tunnel,the seismic wave induced by blasting endangers the safety and stabilization of the surrounding rock and the lining of existing tunnel. Base on the tunnel,The principle of finite-element method is used to analyze vibration influence of tunneling blasting on the existing tunnel,and some numerical simulations were carried out with MIDAS/GTS program.Discussed two tunnel between different distance, different rock type,the blasting of the new tunnel influence on the deformation, velocity, stress of the existing tunnel.Througe the test of the tunnel,analysis of the cause of the cracks,the cracks on the impact of tunnel safety, assess the tunnel safety, combine with cracks in the tunnel of common diseases, giving some cracks repair technology to ensure the safety of the tunnel.In this paper,the value of researching the influence of existing tunnel by the blasting of the tunnel near-by and assess of existing tunnel safety, the blasting on the domestic and international research status and the compare of the new old research method was expounded and generalized detailedly.The stress wave theory and the failure theory of rock blasting was introduced systematically,how to simulate blasting vibration using MIDAS/GTS were put forward.Some different examples about vibration influence of tunneling blasting on the existing tunnel were analyzed by using the transient dynamics method of MIDAS/GTS,which considered some different cases,such as different space, different distance of the tunnels,different types of surrounding rock.The vibration velocity, stress and distortion of lining and surrounding rock were analyzed,analyzed velocity extreme position,time,the peak velocity changes in different cross-section.And some rules and characteristics about the vibration influence of tunneling blasting on the existing tunnel were put forward by analyzing and comparing the different results;Base on the elastic-foundation beam theory and the theory of structural mechanics,using the MIDAS/GTS,analysis the existing tunnel force status with cracks and damage cases and played an important role on the judgment of how the new tunnel blasting vibration influence the existing tunnel lining.Give some advice about the cause of the cracks and methods to repair cracks,so it can effectively improve the reliability of lining structure.