深埋长大隧道施工中存在大量不确定因素,往往难以对涌水量进行准确预测.因此,本文提出基于压水试验和裂隙测量的深埋隧道涌水计算方法.该法采用压水试验附近的裂隙测量对获得的透水率进行修正,根据修正后的透水率对地层进行分层,并把每层的透水率作为随机变量处理,拟合透水率的概率密度函数并推导出总体渗透系数的概率密度函数.最后,采用地下水动力学公式计算出任意涌水量的超越概率,绘制出涌水概率曲线图,并通过实例验证了该方法的可行性.
It is very difficult to predict the amount of water inflow accurately because of lots of uncertainties in deep buried tunnel.Accordingly,a method based on water pressure test and field measurement of fractures is established.Measurement of fractures near boreholes is used to modify the result of field water pressure test.Moreover,rock mass is divided into several layers by modified absorption rate and absorption rate of each layer is considered as a random variable.The probability density function of absorption rate is fitted and the probability density function of permeability coefficient is deduced.Finally,exceedance probability of amount of water inflow can be calculated by groundwater dynamics formula and water inflow probability curve can be drawn.The method is proved correct with a practical example.