| The paper relies on the research background of Daping landslide anti-slide pileregulation project in Sunjiaya tunnel on Fengxi expressway in Chongqing city, due to that theSunjiaya tunnel crosses deep-strata landslide section, super long anti-slide pile is used to treatthe deep-strata landslide body to ensure the tunnel is not affected by the landslide. Combinedthe finite element numerical simulation with the field monitoring data, reinforcementmechanism of super long anti-slide pile reinforcing Daping landslide is studied.Research contents and methods:(1) concrete stress of wall protection of super long anti-slide pile, axial force of steel andearth pressure behind the pile are monitored on the field, strength performance of wallprotection in the construction process of anti-slide force is studied through each kind ofmonitoring data.(2) Settlement variation of deep soil is analyzed through the monitoring data of7surveying slant holes, and the position of sliding surface is determined based on the peakvalue of settlement.(3) Finite element software MIDAS-GTS is used to establish2D and3D model ofanti-slide pile reinforcing landslide, the safety and stability of slope is studied by analyzingthe safety coefficient and settlement changing of landslide.(4)3D finite element model of the construction process of super long anti-slide pile isestablished; compare the simulation results and monitoring data to study the influence ofexcavation on deformation and stress of soil around the pile.The main research results:(1) The change of settlement of deep soil of Daping landslide is acquired through theanalysis of monitoring data of surveying slant hole, and according to the peak value ofsettlement, the shallow and deep sliding surface of landslide is respectively16m~20m and36m~40m.(2) The shallow and deep sliding surface of landslide are drawn through the peak valueof sliding settlement monitored from surveying slant hole.(3) Through2D simulation of anti-slide pile reinforcing the landslide, it is acquired thatthe safety coefficient is increased from0.8875to1.2125after the reinforcement, maximumsettlement at the foot of slope is decreased from71.27cm to5.59cm.(4) Through3D simulation of anti-slide pile reinforcing the landslide, it is acquired thatthe safety coefficient is increased from0.9125to1.3225after the reinforcement, maximumsettlement at the foot of slope is decreased from91.63cm to9.54cm. (5) Comparative analysis is conducted between the monitoring data and numericalsimulation results of the construction process of super long anti-slide pile, combined with thechange of excavation depth of anti-slide pile, it is concluded that the stress and settlement ofsurrounding rock increases with the increase of the depth of excavation in the constructionprocess of anti-slide pile. |
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