基于植被生态需水的隧道排水量确定方法研究

摘要

隧道地下水大量渗漏易造成洞顶影响范围内生态环境破坏,针对如何确定合适涌渗水量以确保生态平衡问题,引入生态学、农学中有关植被生态需水概念,通过调研分析确定隧址区植被所允许的最大地下水位降深,结合地下水动力学方法以及经验公式,确定隧道涌渗水后地下水达到最大降深时疏干漏斗范围及体积；并通过疏干漏斗体积、涌渗水量以及储水系数关系确定隧道所允许排放的最大水量.结合算例并与实际工程中设计排水量进行对比,在考虑隧址区实际工程地质、水文地质条件情况下,所提出方法计算得出的排水标准与实际工程接近.该方法能够达到隧道工程与地下水环境生态平衡,可为隧道建设提供参考.%The large-quantity leakage of groundwater due to tunnel construction will result in the ecological destruction in the top area of mountain.Thus,to appropriately predicate the quantity of water that seeps out of tunnel is significant to the ecological balance.The ecology and agronomy with respect to the ecological water requirements of vegetation were introduced in this paper.Further,the maximum allowable groundwater level drawdown of the vegetation in the tunnel site was determined through investigation & analysis.Then,combining the groundwater dynamics and the related empirical formula,the area and volume of dewatering funnel were obtained when the drawdown groundwater table reached the maximum value after seepage.Moreover,the allowable maximum amount of discharge was determined by the formula which expressed the relationship among the volume of dewatering funnel,water discharge and storativity.Comparing the numerical example with engineering practice,the calculated drainage standard is found close to the standard adopted in engineering practice when real geological and hydrogeological conditions are taken into consideration for the research area.The presented method can balance tunnel engineering construction and ecological groundwater environment,thereby offering reference to tunnel engineering construction.