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Numerical Simulation of the Groundwater Seepage Field of a Tunnel Group in an Ejective Anticline Zone
(1 The State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059; 2 Southwest Electric Power Design Institute Co. Ltd. of China Power Engineering Consulting Group Corporation, Chengdu 610021)
Abstract The ejective anticline is a special geological karst structure found in eastern Sichuan, which may result in engineering hazards and could seriously affect the groundwater environment during tunnel group construction. Since it is difficult to effectively predict the induced variation of a groundwater seepage field by analytical methods, this paper establishes a conceptual model based on the hydrological conditions in the studied ejective anticline zone and predicts variation of the groundwater seepage field using Visual Modflow software. The results show that:1) with the excavation of tunnels, the seepage field changes are obvious and the water level declines sharply, with a maximum drawdown of 48 m and a maximum influential radius of 2.3 km; and 2) after a two-year operation with water being blocked, the water seepage field was almost returned to the normal state before excavation with the water level raised to 1 m below the original level, indicating that the influence of tunnel group construction on the ground water environment decreases gradually. The simulated results are consistent with the measured ones, proving the feasibility of this numerical method.
Abstract:
The ejective anticline is a special geological karst structure found in eastern Sichuan, which may result in engineering hazards and could seriously affect the groundwater environment during tunnel group construction. Since it is difficult to effectively predict the induced variation of a groundwater seepage field by analytical methods, this paper establishes a conceptual model based on the hydrological conditions in the studied ejective anticline zone and predicts variation of the groundwater seepage field using Visual Modflow software. The results show that:1) with the excavation of tunnels, the seepage field changes are obvious and the water level declines sharply, with a maximum drawdown of 48 m and a maximum influential radius of 2.3 km; and 2) after a two-year operation with water being blocked, the water seepage field was almost returned to the normal state before excavation with the water level raised to 1 m below the original level, indicating that the influence of tunnel group construction on the ground water environment decreases gradually. The simulated results are consistent with the measured ones, proving the feasibility of this numerical method.
ZHAO ,
RUI 1,
Xu etc
.Numerical Simulation of the Groundwater Seepage Field of a Tunnel Group in an Ejective Anticline Zone[J] MODERN TUNNELLING TECHNOLOGY, 2015,V52(3): 69-74