Experimental Study On The Performance Of Tunnel Lining Concrete Under "Seepage Stress Field"and Two Factors

The tunnel lining concrete under the ground under the ground is always in a complex environment of erosion,In areas rich in water resources,In addition to bearing the surrounding formation pressure,lining also bear water pressure,due to the permeability of concrete,The groundwater will flow through the cracks and pores in the concrete,and bring the internal pore water pressure to the concrete.With corrosive medium in groundwater,the shield lining will be eroded by the shield of corrosive media,Such as containing chlorine ion and sulfate erosion of groundwater in northwest area of Saline Lake and eastern coastal areas.the shield lining concrete structure in these areas will be affected by the"seepage stress fields"and the interaction of ion erosion.In this paper,a combination of simulation test and theoretical analysis is designed,The law of deterioration of material and structure of lining concrete under seepage stress field and double factor erosion is systematically studied.In order to provide the basic theory and method for long-term safety evaluation of shield lining structure affected by environmental corrosive media.The main contents and achievements of this paper are as follows:?1?By testing the thickness of corrosion layer of concrete block corroded by chloride ion and sulfate ion,XRD diffraction analysis and electron microscope scanning,it is confirmed that chloride salt inhibits sulfate corrosion concrete which causes the time of corrosion of steel bar in concrete is postponed.?2?A"seepage stress field"and a two factor simulated test of erosion environment are designed,the influence of different load and water pressure is considered.At the material level,the residual strength of lining concrete and the concentration of sulfate ion and chloride ion in different depth are obtained under seepage stress field and two factor erosion,The influence of loading level and water pressure on the concentration of sulfate ion and chloride ion was analyzed.The law of penetration of sulfate ion and chloride ion was obtained and the corresponding function model was established.?3?The environment of underground reinforced concrete structure?such as tunnel lining?is simulated through tests?formation pressure,infiltration of groundwater and the joint action of corrosive medium?.By testing the bearing capacity of corroded eccentrically compressed members,the effects of ion concentration and erosion time on the bearing capacity,failure characteristics and tensile strength of the eccentric compression members are studied,and the factors influencing the bearing capacity of the members are analyzed at the component level,and the seepage stress field and the corrosion model of steel in the shield lining structure under double factor erosion are established.?4?A model of resisting force attenuation under the action of"seepage stress field"with SO₄^2-and Cl^-of reinforced concrete lining in eccentric compression reinforced concrete member of tunnel is established.