基于集水廊道的裂隙岩体隧道涌水压力折减分析

Analysis of the pressure reduction of the water in the crack rock tunnel based on the collection corridor

随着隧道建设中,由于对地下水环境的要求日益提高,对涌水的处置,也由“以排为主”向“以堵为主、堵排结合”发生转变。因此对隧道结构在开挖支护过程中,所承受的地下水压力如何分析以及各主要因素影响程度是隧道勘察设计中面临新的地质问题。论文根据裂隙岩体在隧道开挖过程中集水廊道的形成分析方法,推导了地下水水头折减系数公式,并根据公式分析了渗透系数k、埋深高度r_(0)等对水头折减系数的影响。通过分析说明了渗透系数是裂隙岩体水头折减系数的主要影响因素,可以采用注浆降低围岩渗透性,来降低水头折减系数,减少地下水对隧道结构的水头压力。对于全断面注浆封堵开挖,地下水不进入隧道,支护结构所承受的地下水压力可以直接通过水头折减系数与地下水相乘即获得;而在以封堵为主,地下水部分进入隧道,则隧道结构所承受的地下水压力受进入隧道的涌水量与隧道总涌水量的相对关系以及水头折减系数所确定。

With the construction of the tunnel,due to the increasing demand for groundwater environment,the disposal of the incoming water has also changed from“row-based”to“block-based,blocking combined”.Therefore,how to analyze the groundwater pressure and the degree of influence of various main factors in the tunnel structure in the process of excavation and support is facing new geological problems in the tunnel survey design.According to the method of analysis of the formation and analysis of the water collection corridor in the process of tunnel excavation,the paper deducts the formula of the subtractor coefficient of the groundwater head,and analyzes the influence of the osmosis coefficient k and the depth height r_(0)on the water head de-reduction coefficient according to the formula.Through the analysis,it is shown that the osmosis coefficient is the main factor of the water head de-reduction coefficient of the fissure rock body,and the permeability of the surrounding rock can be reduced by injection of slurry,so as to reduce the water head de-reduction coefficient and reduce the pressure of groundwater on the water head of the tunnel structure.For full-sectional slurry sealing excavation,groundwater does not enter the tunnel,the groundwater pressure of the support structure can be obtained directly by multiplying the water head reduction coefficient with the groundwater,while in order to seal the main part of the groundwater into the tunnel,the groundwater pressure of the tunnel structure is determined by the relative relationship between the amount of water flowing into the tunnel and the total amount of water flowing into the tunnel and the water head de-decrease coefficient.