Study On The Structural Design Of Prefabricated Cross Beam And Dynamic Response Of Slope Reinforced By Prefabricated Cross Beam And Anchor Cable

Prestressed anchor cable lattice beam is a kind of slope reinforcement component,which is divided into cast-in-situ and fabricated.Compared with cast-in-situ lattice beam,fabricated lattice beam has the characteristics of less consumables,short construction period and low requirements for slope flatness.It can realize rapid rescue and reinforcement of landslide.At present,the prefabricated cross beam slope protection with prestressed anchor cable is still in the exploratory stage.Although it has been applied in some slope reinforcement projects,it has not formed unified relevant standards and specifications,especially in the earthquake prone areas,there is a lack of reference basis for seismic design.In order to facilitate the mass production and application of prefabricated cross beams and improve the seismic performance of anchorage slope,the stress analysis of prefabricated cross beam structure and the seismic response law of anchorage slope are studied.The main research contents and results of this paper are as follows : The specific research contents are as follows:1)The structural stress analysis of the 600 k N prefabricated prestressed cross beam of the anchorage slope is carried out.The comparison between the bending moment of elastic foundation beam obtained by ABAQUS simulation and that obtained by finite difference decomposition verifies the feasibility of ABAQUS to calculate the internal force of variable cross-section beam.The cross beams with four different slopes and three different foundation coefficients under the anchorage force of 600 k N were designed,and the stress analysis was carried out.The results show that the cross beam structure will not be damaged under normal working conditions.2)The viscoelastic artificial boundary of slope and ground motion input are realized in ABAQUS.Based on the wave theory and viscoelastic artificial boundary theory,the calculation formulas of equivalent nodal forces of each boundary in finite domain slope calculation model are derived.In the seismic analysis of slope site,the boundary equivalent node force is calculated by Matlab programming and the input of viscoelastic artificial boundary and ground motion is completed by secondary development.The effectiveness of viscoelastic artificial boundary application and the accuracy of ground motion input are verified by examples.3)Numerical analysis of dynamic response of slope anchored by assembled anchor cable cross beam is carried out.Based on a slope anchorage project in Kangding,the dynamic characteristics of fabricated cross beam,cast-in-situ beam and anchor cable anchorage slope under horizontal earthquake were studied.The results show that the reinforcement effect of prefabricated anchor and cast-in-place anchor is similar,and the bending moment of cast-in-place beam is larger.Under different seismic waves,the peak ground acceleration amplification factor(PGA)of soil in the fabricated single-row anchor slope increases first and then decreases with the increase of slope height,and reaches the maximum at 3/4 slope height.4)The influence factors of dynamic response of slope anchored by assembled anchor cable cross beam are analyzed.The dynamic characteristics of anchoring slope under different seismic parameters and different elastic moduli are simulated by ABAQUS software.The results show that the axial force response of the prestressed anchor cable near the bottom of the slope varies greatly under earthquake,and the bending moment of the cross beam section near the toe and top of the slope is larger.