Rock Burst Disaster Assessment And Prevention In Xuefeng Mountain Tunnel Of Shanghai-kunming High-speed Railway

Rock burst, a common engineering geological disaster, always happen when large and deep tunnels are excavated. Rock burst disaster, such as peeling, burst loose, and even throwing catapult phenomenon, is a dynamic instability phenomenon occur among brittle rock under high geostress conditions when stored elastic strain energy is redistributed or released. Rock burst disaster, a serious threat to the safety of construction workers, equipments and progress, has become one of the world’s underground engineering problems. Research of the formation mechanism of rock burst, disaster prediction and prevention methods curbing the occurrence of high-strength rock burst effectively to avoid equipment damage, casualties and schedule delays has become a major issue solved urgently for the engineers and technicians.Xuefeng mountain tunnel is deep and long located in Hunan section of Shanghai-Kunming high-speed rail lines, and rock burst may occur in this tunnel. For this problem, we use a variety of methods for each segment of the tunnel to forecast the rock burst possibility and analyze the role of Shotcrete protection measures in the fight against rock burst. Works in this thesis are as follows.(1) Summarize the natural geographical features, lithology, geological structure, hydrogeological and engineering geological features characteristic in Xuefeng Mountain Tunnel.(2) Do some simple plane simulations of the post-secondary stress field surrounding rock tunnel after excavation and get the distribution law of tunnel surrounding rock secondary stress field.(3) Predict the rock burst possibility in each segment of the tunnel by theoretical calculations and numerical simulation techniques using stress intensity ratio method (single factor). Meanwhile, evaluate the risk in typical tunnel section based on fuzzy matter-element theory.(4) Do some numerical simulations using the finite difference software FLAC3D to analyze the role of Anchor and Shotcrete support in preventing the rock burst.All of the forecast and protection measures proposed for rock burst in Xuefeng Mountain tunnel in this thesis will provide some reference and reference value for similar projects at home and abroad.