Study On Deformation And Failure Characteristic Of Water Bursting Protective Rock Formation In Deep Tunnel

With the vigorous development of the western development in our country,traffic tunnel、hydropower station、inter-basin water transfer and the rapid development of deep mining and other underground engineering construction in mountains region,the engineering geological conditions become increasingly complex,Geological problems become more and more challenging.Especially in the deep,High pressure water inrush, mud, rock burst, landslides often appear,underground engineering assignments are in the great threat of all kinds of unexpected disasters.Therefore it has great realistic and far-reaching significance to strength the study on deformation and failure mechanism of protection rock structure in deep tunnel.In this paper,using morden research methods such as model experiment and numerical simulation,study on confining pressure level、lateral pressure coefficient and the length of the crack.This paper got main conclusion as follows:(1) Protection rock’s progressive failure characteristics was be explored under high ground stress and high confined water stress, 3d digital camera and acoustic emission location was used in the model test,It is a helpful exploratory try.(2) The bearing capacity of protection rock will increase with the increasing of confing pressure.The rock will break from fragile character to plastic character.The crack propagation from the middle to outside of the protection rock’s free surface.The displacement when the confining pressure is high is greater than when the confining pressure is low.The rock’s break surface is in cone,and it has obvious water inrush channel in the compression surface.(3) The rock’s bearing capacity is strongest when the lateral pressure coefficient is 1.The rock’s bearing capacity will go down no matter when the lateral pressure coefficient become bigger or smaller.With the coefficient’s increasing(the degree of bias improving),the rock break clear-cut.When the coefficient low,the rock break is in compression-shear damage,when high,in integral shear failure.(4) The rock’s bearing capacity will go down when there is crack in the rock.The crack propagation will starts at crack tip when the rock in complex stress state.With the crack’s length change,failure pattern will change as the same.