Research methods: On the basis of survey and design data, studies are made on the karat development regularity and on the relations between the water inflow and the karat development by investigations on the engineering geology and hydrogeology of ground surface along the tunnel alignment and inside the tunnel.
Research results :By means of studying on the development states and distribution regularity of the karats in the prediction region , it is concluded that huge and deep fractures control the development of the deep karat caves and underground rivers and the critical water inflow sections within the tunneling region are determined; Small-medium distance electrical prediction methods compatible with the prediction aims are selected for the detailed prediction and determination of the water inflow scales in the critical water inflow sections. The geological data recorded inside the tunnel are used to modify the prediction programme and the relevant technical parameters so as to gradually optimize the prediction system.
Research conclusions: Huge and deep factures control the development of the karsts and the general development orientations of the large-scale water-filling karst caves are the same as the orientations of the fractures; the highly- accurate electrical prediction methods for small-medium distances, which are more sensitive to water than elastic- wave prediction method , is suitable for the detailed predictions in critical water inflow sections. A combination of different prediction methods should be adopted for the prediction of the water inflow in karst regions so as to improve the prediction reliability and the working efficiency; the prediction process is a gradually-optimized process.
2007, Vol. 24 
