| Slope instability has long been one of the main focuses of research by experts and scholars at home and abroad.Slope instability causes immeasurable property losses and a large number of casualties in China every year.Vegetated concrete slope protection,an environment-friendly slope protection technology,can improve the ecological environment around the project and enhance the economic benefits of the slope.In this paper,the stability analysis of the new-type vegetated concrete slope developed by the group is carried out under the coupled action of earthquake and rainfall.In addition,I made a numerical analysis of the ecological slope protection and cone slope of the Beijing-Taiwan Expressway reconstruction and expansion project through ADINA.Firstly,the efficiency of the numerical simulation method in this paper is verified by comparing with the shaking table model tests in the existing papers,and then the stability response law of ecological slope protection and cone slope under three working conditions--earthquake alone,rainfall infiltration and earthquake-rainfall coupling is analyzed.The main research contents and conclusions are as follows:(1)The PGA acceleration amplification coefficient and peak dynamic earth pressure response at the vertical monitoring points,the PGA acceleration amplification coefficient at the slope monitoring point and the displacement response at monitoring point slope shoulder in the literature were calculated by ADINA for ecological slope protection and natural slope under the action of artificial waves at 1m/s~2,and are compared with the related results obtained by shake table model tests and FLAC3D numerical simulations in the literature to verify the efficiency of the simulation method in this paper.(2)According to the engineering design data,a finite element model was established to analyze the initial stress field,the initial displacement field and the safety factor of the ecological slope protection and the abutment cone slope under the self-weight.The research results show that under the action of its own weight,the ecological slope protection and the abutment cone slope did not suffer from overall instability,shallow instability,and failure of slope protection blocks.(3)Carrying out the stability analysis of ecological slope protection and abutment cone slope under the separate action of seismic waves of different wave types and different peak accelerations.To analyze the PGA amplification factor,slope stress response,displacement response of the slope protection block,and safety factor of the slope data monitoring point under different seismic conditions of ecological slope protection and abutment cone slope.The research results show that with the continuous increase of the peak acceleration of seismic waves,the PGA amplification coefficient of monitoring points on the slope increases,and the change law of the PGA amplification coefficient is similar to the"whip sheath effect";The safety factor of ecological slope protection and abutment cone slope is reduced,Under the action of E1(0.1g)and E2(0.3g)earthquakes,the safety factors of ecological slope protection and abutment cone slopes meet the requirements of the code,there is no overall instability occurring;The shear stress of slopes increases,and the stress concentration area at the part foot of the ecological slope protection and the abutment cone slope increases.Under the action of the E1(0.1g)and E2(0.3g)earthquakes,the ecological slope protection did not suffer from overall instability,shallow instability,and loss of slope protection blocks;Under the action of the E1 earthquake(0.1g),the abutment cone slope did not suffer from overall instability,shallow instability,and failure of slope protection blocks;Under the action of the E2 earthquake(0.3g),the local soil shear stress at the foot of the cone slope exceeds the shear strength of the soil,and shallow instability may occur.Under the same peak acceleration EI-Centro wave and artificial wave,the PGA amplification factor,slope shear stress,slope protection block and slope displacement response of the abutment cone slope gradually increase,the safety factor gradually decreases,and the dynamic response is more significant than that of ecological slope protection.(4)Carrying out the stability analysis of ecological slope protection and the abutment cone slope rainstorm(5.8 mm/h)and heavy rain(11.6 mm/h)for 1h.To analyze the effective pore water pressure in the slope,the vertical displacement of the slope protection block,the vertical displacement of the slope,and the safety factor.The research results show that with the increase of rainfall intensity,the effective pore water pressure in the ecological slope protection and the abutment cone slope,the vertical displacement of the slope protection block and the slope body increase,the safety factor gradually decreases;As the rainfall intensity increases,the safety factor gradually decreases.Under different rainfall conditions,the safety factors of the ecological slope protection and the abutment cone slope meet the requirements of the specification,indicating that there is no overall instability;Under the same rainfall conditions,the vertical displacement of the ecological slope protection and the abutment cone slope is smaller than that of the slope protection block,indicating that the ecological slope protection and the abutment cone slope have not suffered shallow instability.Under the same rainfall conditions,the vertical displacement of the abutment cone slope and the reduction of the safety factor are more than the ecological slope protection;the effective pore water pressure is lower than the ecological slope protection.(5)Carrying out the stability analysis of ecological slope protection and abutment cone slope under the coupling effect of E1 earthquake action(0.1g)seismic wave rainstorm(rainfall for 1h).To analyze the acceleration response peak value and PGA amplification factor of each data monitoring point on the slope surface under the coupling effect of the seismic wave torrential rain(rainfall for 1h)of E1 earthquake action(0.1 g),slope protection block and slope displacement response,and the shear stress response of slope.The research results show that the dynamic response of each parameter of the ecological slope protection and the abutment cone slope under the coupling action of E1 seismic action(0.1g)seismic wave rainstorm(rainfall for 1h)is similar to that under the action of earthquake alone.However,the acceleration response peak value and PGA amplification factor of each data monitoring point of the ecological slope protection and the abutment cone slope surface,the sliding displacement of the slope protection block,the vertical displacement of the slope,and the slope shear stress are all more than their dynamic response under the separate action of the earthquake;The safety factors of the ecological slope protection and the abutment cone slope does not meet the requirements of the specification,indicating that the ecological slope protection and the abutment cone slope both are instability;part of the slope protection blocks on the slope face fell off and was damaged.Under the separate action of the E1 earthquake(0.1g),the PGA amplification factor of each data monitoring point on the ecological slope protection and the abutment cone slope is not much different.Under the coupling effect of the E1 earthquake(0.1g)and heavy rain(rainfall for 1h),the PGA amplification factor of each data monitoring point on the ecological slope protection and the abutment cone slope is poor.The value gradually increases as the slope height increases.Under the same earthquake and rainfall coupling conditions,the ecological slope protection has better anti-seepage and seismic performance than the abutment cone slope.This paper presents a numerical analysis of the stability of the new-type vegetated concrete slope applied to the reconstruction and expansion of the Tai’an-Zaozhuang(Shandong-Jiangsu border)section of the Beijing-Taiwan highway under different working conditions,and demonstrates the applicability of the new-type vegetated concrete slope in this project,which is of great significance for breaking through the ecological protection design concept of the northern motorway in China,guiding the reconstruction and expansion project of the Beijing-Taiwan highway and further promoting the vegetated concrete slope protection technology. |
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