Risk Assessment of Water Inrush in Karst Tunnels Based on the Efficacy Coefficient Method

With the rapid development of China's economy, more and more long-deep tunnels are under construction, especially in the mountainous area of western China and in karst areas [1-2], which pose a great challenge for tunnel engineering. Long-deep tunnels are always buried in complex geological conditions with high geo-stress, high water pressure, strong karst geology, and construction disturbance Additionally, it is quite difficult to make a