| The loess area is one of the most developed regions of geological hazards in China.As the development of cities and towns,a large number of artificially excavated high-steep landslides are produced in the loess area.Because these high-steep landslides are close to residential areas,factories and mining areas,and roads,the construction work surface is narrow and space is limited.It is difficult for traditional treatment methods to achieve rapid disaster recovery.Based on a high-steep loess landslide treatment project,this paper carried out on-site investigation,indoor physical model test,theoretical analysis,numerical simulation and field monitoring and other research methods to adopt the synergistic mechanism of reinforced soil-frame-anchor combination system on the high-steep loess landslide.The main research results are as follows:(1)on the basis of field investigation,the instability characteristics of high-steep loess slopes are discussed;based on the concept of synergy,in order to solve the problems of rapid repair and large deformation displacement of high-steep loess slope,the composite structure of reinforced soil with limited backfill and frame beam with anchor is proposed to strengthen the high-steep loess slope.Based on the numerical calculation model,the synergy mechanism of the combined system is studied,and the concepts of stability coefficient and load sharing ratio are introduced,and the factors affecting the stability of the combined system are discussed,and the sensitivity of each factor is analyzed.Summarizes the variation law of the stability factor and structural load sharing ratio of the combined system with various influencing factors.The results show that the anchor cable prestress design parameters have a greater impact on the stability factor and structural load sharing ratio of the system,which is a follow-up laboratory test and theoretical analysis for reference.(2)The indoor physical model test was carried out to study the action mechanism of reinforced soil with limited backfill and frame beam with anchor system,and the synergistic effect of the combined support system was verified.The cooperative working mechanism of composite system was analyzed from the stress angle.According to the theoretical of additional stress method,the calculation formula of equivalent stress of soil under the action of prestressed anchor cable was established;the calculation method of safety factor of composite structure considering additional stress of prestressed anchor cable was established by introducing the theory of slice method.Through the analysis of engineering examples,the relationship between prestress and safety factor was discussed.It shows that the calculation method in this paper reflects the prestressed effect of anchor cable,and shows that the anchor cable was very important to the overall stability of the support structure.(3)Taking Mingdi 1# slope as the engineering background,the FLAC3 D numerical analysis model of the composite structure of with limited backfill and frame beam with anchor was established.Considering the natural working conditions and rainfall conditions,the synergistic effect of the supporting structure was analyzed;considering the effect of the traffic load on the top of the slope,the synergistic effect of the composite structure was analyzed,and evaluate the influence of the traffic load on the stability of the composite system.According to on-site monitoring data and numerical model results,the practical application deformation characteristics and laws of the composite structure was obtained,and the effectiveness of the composite structure of reinforced soil with limited fill and frame anchor was verified,the key technical problems of rapid repair,limited support space,large reinforcement deformation and incompatible deformation of loess high-steep landslide have been successfully solved. |
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