Abstract:Since entering the 21st century, with the improvement of the country"s comprehensive strength and the rapid development of economy, convenient transportation is a major work of China"s rapid development. Every mountain tunnel, water bridge, so that China"s infrastructure level far ahead of the world. However, the vast domestic, geographical position relative disparity between the east region, especially in the southwest area due to the geographical position is more complex, most of highway is located in the mountains, make the engineering construction is difficult, especially some super-long tunnel most tunnel through the cave, coal mine goaf, high gas area, rock burst and the rich water area, such as complicated geology, It brings many difficulties to construction and later operation and maintenance. In the process of operation of some long tunnels in China, the lining falls out, the road arch and the structure deformation often occur. In this paper, taking The Bayue Mountain tunnel of Chongqing and Chengdu expressway as the background, OCTEM is used to detect the specific range of mined-out area of coal mine behind the tunnel lining, which solves the situation that the detection effect of traditional natural electromagnetic method is not ideal due to the influence of site topography and environment, and also accumulated valuable experience for other similar projects..
