Research On The Supporting Measures Of Shaofang Yakou Sandstone Tunnel Passing Through Rich Water Area

The tunnel construction in southwest China is often faced with the situation of the soft surrounding rock crossing the rich water geological body,and its construction difficulty is large,the progress is slow,the project cost is high,the accident frequently becomes the common problem.The careless attention to the tunnel excavation of the water-rich sandstone tunnel,which may bring about the accident of collapse,water inrush,mud,and even initial support loss,and support structure beyond limit.Based on the survey data of tunnel design,this paper studies the safety support measures of the sandstone tunnel through the water-rich geological zone.This paper revolves round the tunnel surrounding rock properties,researching the effect of groundwater seepage stress to the stability of the tunnel and analyzing the differences on the impact of different supporting measures on tunnel stability,by means of theoretical analysis,field test and numerical simulation,field monitoring,which helps to determine the best support plan in the end.At the same time,demonstrating the reliability of numerical simulation in the engineering scheme by the monitoring data of the settlement and surrounding convergence project.Based on the research results of the paper,reasonable Suggestions are put forward to avoid the occurrence of disasters.The main research contents are as follows:(1)From Shaofangyakou argillaceous sandstone itself,in combination with hydrogeological environment,study the engineering mechanical properties of rock and rock mass parameters by theoretical calculation of transformation,the parameter for the constitutive model for data base.Field using advanced geological forecast,high-density electrical resistivity exploration,field exploration,clear water rich period of adverse geological range of surrounding rock and rock type,embodies rich water pile number range and rich water state,to make preparation for establishing a threedimensional model.(2)In this paper,the deformation characteristics and laws of tunnel excavation in the soft rock rich soil mass are studied,and the theory analysis of the supporting principle of soft rock tunnel provides the theoretical basis for the construction of tunnel construction.(3)Finite difference method of fluid-structure coupling between seepage and the original rock stress,contrast analysis with seepage and seepage of two kinds of working condition of tunnel stability,simulation of tunnel excavation supporting tunnel under the condition of no water penetration is severe,surrounding rock stress and pore water pressure change rule after excavation.(4)Treat the New Austrian method supporting principle as the core,refer to the literature and analogy to the similar engineering construction experience,put forward three kinds of tunnel support scheme,simulating three plans and spot plan with FLAC3 D respectively,contrast four schemes of the plastic zone,displacement of stress nephogram and size.The comprehensive consideration factors mainly depend on the support effect and the engineering cost.Plan two is considered as the optimal solution to meet the safety requirements of the tunnel and avoid excessive support and waste of engineering expenses.(5)Applied the thorough monitoring information feedback process to the field monitoring,use the surrounding rock deformation curve data,verify the consistency of the simulation and actual analysis,more reasonable support and construction scheme is put forward.Provide scientific and practical theoretical basis for actual production.