Using coupled fluid-solid theory to forecast the water inflow for conveyance project of Dahuofang reservoir

摘要

Water inflow is a key parameter in the design and construction of tunnel with rich water. The geological condition of Dahuofang water conveyance project is complicated and the fault structure is well developed, which is endowed with abundant water, such that gushing water is prone to happen. According to the geological survey of Liuhe section, which is the key control of the project, three-dimensional numerical model was built to represent the actual mechanical behavior under the scope of coupled fluidsolid theory. FISH language program was compiled to record the water inflow information in the process of excavation by using 'gp_flow' command. At the same time, empirical formula was applied to predict the water inflow amount. It was indicated that large velocity of flow water before working face of fault and vault of section 15 + 750 was observed, which will lead to higher gushing water hazard. Both numerical result and empirical value fit with the field survey very well, in which the maximum water inflow reached 590 m3/d. It was proposed that strengthening the geological forecast in the process of construction is required. According to the actual survey value, geological parameters are modified to guarantee the safety of the project.