Study on Catastrophe Information Characteristics of Water Inrush in Karst Tunnel by Drilling and Blasting Method

Abstract

When building tunnels in karst areas, the hidden high‐pressure water‐bearing karst caves are prone to cause geological disasters such as water inrush and mud gushing. In order to study the disaster process of water and mud resistant rock mass with the quasi‐masonry structure and the accompanying catastrophe information of water inrush in karst tunnels by the drilling and blasting method, a new method based on the DEM and fictitious joint technology is adopted to simulate the evolution process of water inrush and study the evolutionary characteristics of catastrophe information like seepage pressure and displacement under the conditions of different joint inclination angles, tunnel depths, and thickness of the water and mud resistant rock mass. The research results show that (1) the seepage pressure and displacement in the water and mud resistant rock mass decrease and increase respectively along the water and mud resistant rock mass from top to bottom in the process of water inrush. (2) The displacement and seepage pressure in the water and mud‐resistant rock mass increases with the increase of the joint inclination angle. The greater the tunnel depth and thickness of the water and mud‐resistant rock mass, the faster the propagation speed of the fissure zone. (3) With the increase of the water and mud‐resistant rock mass thickness, the failure mode of the tunnel outburst layer structure gradually changes from the overall collapse to the partial collapse of the vault to form a relatively stable slump arch. The research results can provide some guidance for tunnel construction in the karst tunnel.