Abstract:

The design of conventional reverse slope drainage is based on the design water inflow. However, due to the inaccurate estimation on the water inflow, the capacity of the drainage facilities designed is often inadequate or surplus, which may result in water gushing disaster or resource waste. In the paper, the concept of longdistance reverse slope drainage based on the prediction and dynamic monitoring of the water inflow is proposed on basis of the design concept "providing an integrated drainage system in advance and making local optimization during tunneling". The technology described in the paper can position and forecast the water bearing zone and the water inflow ahead of the working face accurately by using the transient electromagnetic technology and induced polarization technology. Furthermore, an optimized drainage formula based on the drainage cost is proposed, and the classification of the pumping stations and the selection of the pump power are optimized. Meanwhile, the water inflow is monitored dynamically, the drainage facilities are arranged based on the monitoring data, and the technology of the enhancement of pumping station is proposed. The technology has been applied in the construction of Liupanshan tunnel on DongMao highway in Ningxia autonomous region and satisfactory effect has been achieved.

Key words: highway tunnel, Liupanshan tunnel, reverse slope drainage, water inflow prediction, dynamic monitoring, cost minimization