Methodology for the Prediction of Water Gushing in Tunnels in Igneous Fracture Tectonic Zones: A Case Study of a Tunnel in Guangdong Province, China

The disaster of water gushing is very liable to occur when tunnels are built in the water-rich fracture structures in igneous rock areas. Different sources of water gushing result in different sizes of disaster. The safety of human life and property are in danger. For the prediction of water gushing in tunnels, the fuzzy clustering method was used to determine the source of the water gushing in this paper. The problem of subjectivity in traditional identification methods was solved by this method. On the basis of the fuzzy clustering method, dynamically changing parameters of the effective radius of the water gushing were introduced and regressed with the dynamic monitoring data and the hydrogeological survey results in an improved method for predicting water gushing. Then, an improved method for predicting water gushing, considering the source, was proposed. A deep underground, extra-long tunnel under construction in the igneous region of southern China was used to verify the soundness of this improved method. Research results showed that the water gushing into the tunnel had a low correlation with surface water with a similarity index of λmin=0.3967 in the results of the second test. The water came mainly from within the rock mass. The effective radius were jointly determined by the average thickness of the rock aquifer and water gushing time, together with a positive correlation. The period of water gushing was divided into three stages. The predictions had a good accuracy rate with an error of 10% or less. These results could provide a reference and theoretical support for site construction.