Study On Dynamic Response Law And Sensitivity Of Blasting Excavation In Deep Tunnel Cross-Fault Area

With the rapid development of the social economy,the demand for resource mobility upgrading among major regions is becoming more and more urgent.It is imperative to improve and strengthen the task of building various types of transportation networks.At the beginning of the design of traffic lines,factors such as economic development,population concentration,engineering construction,and national strategy are often considered.Therefore,in the process of tunnel construction,it is inevitable that it will encounter bad geological sections such as fault fracture zones.A large number of engineering practices and researches have shown that the deformation and damage of tunnel surrounding rock are controlled to a large extent by weak structural planes such as fault fracture zone.Once the soft structural plane is relatively displaced,the tunnel structure will be destroyed and the surrounding rock will be collapsed.And other significant adverse effects.Therefore,in view of the above problems,this paper takes the fault zone of the North Tianshan Tunnel in Xinjiang as the engineering background,and uses the ANSYS/LS-DYNA software simulation as the analysis method to study the dynamic response law of blasting excavation in the deep tunnel cross-fault area and conduct faults.The exploration of the sensitivity of width,ground stress and surrounding rock grade to the dynamic response of tunnel blasting excavation has important theoretical guiding significance for tunnel design and construction.The main research results are as follows:1.Taking the fault zone of the North Tianshan Tunnel in Xinjiang as the engineering background.The ANSYS/LS-DYNA is used to simulate the blasting excavation of fault-containing tunnels.The vertical vibration velocity peak,the vertical displacement peak and the maximum principal stress additional peak value of the representative key points in the surrounding rock of the tunnel cross-fault area are discussed.2.The distribution and levy of the blasting excavation promote the change and distribution of the dynamic response characteristics of the surrounding rock and the surrounding rock along the axis,which provides an effective reference for the design and construction of similar tunnel construction in the future.3.The fault width,the magnitude of the ground stress(the depth of the tunnel)and the level of the surrounding rock are selected as the variables.The scientific methods of three-factor and three-level orthogonal tests are used to investigate the sensitivity of the multi-factor intersection to the dynamic response of the fault tunnel..In this experiment,the finite element software was used to simulate the dynamic response analysis of tunnel blasting excavation,and the peak vibration velocity,peak displacement and peak value of the maximum principal stress added to the tunnel vault were used as evaluation criteria.Finally,the visual analysis method and variance were used.Analytical analysis of the sensitivity of three factors to fault tunnels and their response.Based on the frontier hot subject issues,based on the existing theory and engineering practice,the numerical simulation analysis method is used to carry out the dynamic response analysis and sensitivity research of blasting excavation across the fault tunnel.The high practical application value provides an effective research method for systematically analyzing the blasting excavation problem across the fault tunnel.