| There are a large number of mountainous areas in China,and they are poor due to the constraints of the terrain.In order to solve the problem of transportation infrastructure in poor mountainous areas and further win the battle against poverty,China has made a lot of investment in railroads.Xingquan Railway is a national railroad Class I single-line passenger and freight common line electrified railroad in China,connecting Xingguo County,Ganzhou City,Jiangxi Province and Quanzhou City,Fujian Province,in which there is an 80 m high side slope at Dehua Station located in Quanzhou,Fujian Province.Since the Dehua station is located in the subtropical maritime monsoon climate zone,and according to the China Earthquake Parameter Zoning Map(GB18306-2015),the peak acceleration of ground vibration in this section is 0.05 g,and the characteristic period of ground vibration response spectrum is 0.35 s.Therefore,the slope of Dehua station faces the double influence of strong rainfall and earthquake,and it is necessary to study its seismic stability.To address the appeal problem,this paper,based on the project "Research on long-term stability and monitoring and evaluation technology of high and steep road graben slopes",after fully investigating the stability of slopes under rainfall and earthquake at home and abroad,takes the slope section of Dehua station as the research object and conducts in-depth research on the seismic stability of slopes under different rainfall intensity and earthquake intensity by combining basic physical and mechanical tests of soil,large shaking table tests,numerical simulations and theoretical calculations,etc.My main content is:(1)The rainfall seepage theory of slope,the seismic stability theory of slope and the stability of slope under the coupling effect of rainfall and earthquake were fully investigated(Chapter 1).(2)The basic physical and mechanical properties of the slope soil were tested,including the direct shear test at different water contents,the saturated permeability test and the dynamic triaxial test at different dynamic stresses.From the tests,it can be seen that the shear strength of the soil decreases with the increase of water content,the damping ratio of the soil increases with the increase of dynamic stress amplitude,and the dynamic modulus of elasticity of the soil decreases with the increase of dynamic stress amplitude and increases with the increase of surrounding pressure(Chapter 2).(3)Three groups(A/B1/B2)of large shaking table model tests with different working conditions were conducted.Combining the test phenomenon and monitoring data analysis,it was found that rainfall would reduce the seismic stability of the slope,the support structure could improve the seismic stability of the slope,and the self-oscillation frequency of the slope would decrease with the increase of the damage of the slope(Chapter 3).(4)Rainfall and seismic simulation of slopes by Geo-studio and FLAC3 D.The stability of slopes under different rainfall conditions,support conditions and seismic conditions is studied.It can be found from the numerical simulation that different rainfall conditions affect the infiltration of rainwater in the slope,and the horizontal displacement and the maximum shear strain increment of the slope under the rainfall condition are larger than those without rainfall,and the support structure can effectively limit the horizontal displacement and the maximum shear strain of the sliding surface(Chapter 4).(5)After fully considering the effects of rainfall and support structure,the seismic stability of the slope is calculated by the proposed static method.For the fast and accurate calculation and the generalizability of the method,a set of slope safety coefficient calculation program was written by using python.The safety factor of the slope in extreme cases was calculated by the program as 1.08(Chapter 5). |
