Protective Measures And Numerical Analysis For Safety Of Adjacent Existing Tunnel During Cut Slope Construction

ABSTRACT:Nowadays more and more new roads get close or cross over the existing underground structures, with the conservation and intensive land use policy and the increase of engineering project. The construction of cutting will inevitably impact on adjacent existing tunnel. If the soil displacement on existing tunnel caused by cutting excavation exceed a certain degree, it will cause the tunnel lining tilt, cracking, safety performance lessen, etc., which will threat to the security and normal use of the existing tunnel. So the research on cutting excavation effects on nearby existing tunnel foundation has very important practical significance and application value. A numerical model of the cutting excavation adjacent to tunnel is built with ANSYS. Combined with engineering experience, the prevention and control measures were developed and the following conclusions are obtained:(1)Based on the theoretical analysis, Numerical model was established by ANSYS to analyze the influence of cutting excavation on existing tunnel(2)With numerical simulations of statics response analysis by both up-down excavation method and left-right excavation method in existing tunnel lining have been studied, law of their influence on existing tunnel lining were achieved, which showed that up-down excavation method was more safer than left-right excavation method.(3)Based on practical engineering, analysis model, which would be used to study the vibration influence of blasting excavation of cutting on adjacent existing tunnel lining, was built. The result got by simulating blasting excavation of cutting showed that method of blasting excavation is not suitable for this cutting.(4)With practical projects has been combined, aiming at ensuring construction safety, safety measures, which would provide guidance for safe construction on site, was proposed.