矿山法城市隧道运营期排水量与水压力关系的一种预判方法

预判隧道运营期排水量与二衬外水压力的关系是城市隧道设计中的关键问题，而高、低水位隧道的渗流场影响范围存在较大差别，理论预测隧道排水量和水压力时不能忽视其边界效应的作用。首先，利用地下水渗流理论、复变函数保角映射理论和二维稳态流动的复变函数理论，并结合围岩-支护结构精细化模型和气象因素，分别对高水位和低水位隧道运营期排水量及二衬外水压力进行分析，然后依托在建的深圳东部过境高速公路连接线工程，对不同注浆圈渗透系数和厚度条件下城市隧道排水量及水压力之间的关系进行研究，结果表明:无论低水位还是高水位城市隧道，二衬外水压力均随隧道排水量增加呈线性降低，且注浆圈渗透系数的变化相比其厚度的变化，对水压力随排水量的折减作用更加明显；注浆圈渗透系数的增减比例相同时，低水位城市隧道水压力随排水量的折减速率更快，而注浆圈厚度增减量值相同时，高、低水位隧道水压力随排水量的折减速率基本相同。

A METHOD TO PREDICT THE RELATIONSHIP BETWEEN WATER DISCHARGE AND PRESSURE DURING OPERATIONAL PERIOD OF CITY TUNNELS CONSTRUCTED USING THE MINING METHOD

To predict the relationships between water discharge and secondary lining external water pressure over the operational phase is a key issue in tunnel design. Differences in the reach of the seepage field of tunnels subject to high and low water levels requires the consideration of boundary effects when theoretically predicting the water discharge-pressure relationship. This study analyzed water discharge during tunnel operational stage and the secondary lining external water pressure of tunnels subject to high and low water levels, employing the groundwater seepage theory, the complex conformal mapping theory, and the complex two-dimensional steady flow theory combined with the refined model of surrounding rock-supporting structure and the meteorological factors. Based on the being constructed connecting line project of Shenzhen Eastern Transit expressway, the relationship between water discharge and pressure of city tunnels was investigated considering various permeability coefficients and thickness of the grouting circle. The results show that the secondary lining external water pressure reduces linearly as the tunnel water discharge increases, regardless of what the water level is. The effect of the variation in permeability on reducing water pressure due to water discharge appears to be more prominent than the variation in the thickness of the grouting circle. With the same increase or decrease proportion of permeability coefficient of the grouting circle, the reduction rate of water pressure-discharge of city tunnels with low water level is faster, whereas with the same change in the thickness of the grouting circle, the reduction rates of water pressure-discharge of city tunnels of both high and low water levels are almost the same.