水库蓄水对铁路隧道安全的影响

Influence of Reservoir Filling on the Safety of Railway Tunnel

为定量分析隧道施工及水库蓄水对隧址区地下水及周边生态环境的影响,以某铁路大梁山隧道为例,运用地下水渗流理论和三维有限差分方法,对比分析隧道施工降水前后隧址区地下水的运移变化情况,并结合剖面二维渗流模拟,开展了瓦沟台水库蓄水对隧道施工安全的影响研究。结果表明:瓦沟台水库和隧道DK56+724~DK57+000段位于大梁山山脊东西两侧不同的地下水流系统中,它们之间的水力联系并不紧密;水库蓄满水后,周边地下水位呈现先快速上升后渐平缓的现象,在水力梯度作用下,起初地下水接受水库水补给,但在历时近2年后,地下水将向水库排泄,该水力联系发生转变的时间远小于地下水从大梁山山脊流动到水库所需时间。综上可以判断,瓦沟台水库蓄满水对大梁山隧道安全的影响不大。

To analyze the effects of reservoir filling on groundwater and ecological environment quantitatively during tunnel construction,groundwater migrations were simulated and compared before and after precipitation in construction by means of groundwater percolation theory and 3D finite-difference method around Daliang Mountain tunnel of a railway. On this base,influence of Wagoutai Reservoir filling on tunnel safety was analyzed by using sectional twodimensional numerical modeling. The results were as follow. Firstly,Wagoutai Reservoir and tunnel section from DK56+724 to DK57+000 respectively located in different groundwater flow systems on both sides of the Daliang Mountain ridge,thus the hydraulic connection between them was not closely related. Secondly,in the initial period of Wagoutai Reservoir being fully charged,groundwater level nearby increased rapidly,and then increased slowly. Under the action of hydraulic gradient,groundwater was recharged for nearly two years by reservoir water,and then would discharge to the reservoir. The transfer time of two yeas was much less than the time needed for groundwater movement from Daliang Mountain ridge to reservoir. Since that is so,it follows that Wagoutai Reservoir being fully filled has less effect on tunnel safety of Daliang Mountain,and the research conclusions can provide academic basis in railway's design and construction.