Tunnel introduction: After measurement, the main lane of the existing tunnel in Shandi Village is 1,626 meters long, with a maximum length of about 1.8 meters and a minimum of about 1.4 meters. It includes 9 main lanes, a compound lane of 304 meters, and a branch lane of 13,666 meters. There are 2 large caves, 6 small hiding cave entrances, 4 traps, and many tunnels that radiate to nearby villages such as Wangkan and Sufeng.