Study On Stability Evaluation And Control Measures Of Luoyugou Landslide In Tianshui City

The Landslide Research Area of Luoyugou Area Reconstruction and Resettlement Housing Project is located in Qinzhou District,Tianshui City,Gansu Province.The area is located in the south of Gansu Province and is a high-prone area for geological disasters.There are a large number of hidden dangers of landslide hazards in the area,which are concentrated in the composite area of NWW and NE-oriented fold shafts and compression-torque strike-slip faults and strong earthquakes near Luoyugou.The total number of landslides in the area accounted for 51.4% of the total number of landslides in Qinzhou District.This situation has had a major impact on the safety of people's lives and property in the region.In order to relocate residents in areas with severe geological disasters to different places,it is necessary to carry out deep excavation and high-level filling and reconstruction of the old landslide areas in Luojinggou area,and provide engineering sites for the reconstruction of resettlement houses in Luojinggou area.Based on this,the paper takes the Luojinggou landslide where the proposed project site is located as the research object.Firstly,based on the collection of regional geological environment and loess landslide and other research materials,through detailed on-site investigation and surveying,exploration,indoor geotechnical tests,etc.The development characteristics,scale,deformation and failure characteristics of Luojinggou landslide are qualitatively analyzed,and the interaction between landslide and engineering construction is qualitatively analyzed.Secondly,the stability coefficient and residual sliding force of the landslide under different working conditions are calculated by the limit equilibrium transfer coefficient method.Finally,a safe,reliable and economical landslide comprehensive treatment design proposal is proposed.The following main results:(1)Through on-site investigation and surveying,exploration and indoor and outdoor tests,it is determined that the Luojinggou landslide can be divided into three levels,namely,the first-level landslide H,the second-level landslides H1,H2 and H3,and the third-level landslides H1-1 and H3-1.H3-2.According to the scale of the landslide,the nature of the landslide and the soil of the slip zone,it is concluded that the landslides at all levels belong to the large loess-shale contact zone landslide;the mechanical properties formed according tothe landslide are all traction landslides.Among them,the secondary H1 and H2 landslides directly threaten the project areas A1 and A2.(2)Firstly,the shear strength index is determined by back analysis model.The index is compared with the index determined by experiential method and experimental method,and two important parameters C and ? used for calculating stability are finally determined by using a certain influence ratio.The calculation of the landslide stability under different working conditions by using the transfer coefficient method shows that the first-level landslide H is in a stable state,while the secondary landslides H1 and H2 are in a basically stable state under heavy rainfall conditions,and the secondary landslide H1.The stability coefficient of H2 under seismic conditions is relatively small,and it is in an unstable state,especially the residual sliding force is large,and there is the possibility of instability.(3)According to the scale of landslide,deformation and failure characteristics,steady state and potential threat areas,the comprehensive engineering treatment plan of anchor cable anti-slide pile + Gufangba is proposed from three comparison schemes.The research results have important engineering practical significance for the project safety of the Luojingou area reconstruction and resettlement housing project,and also have important reference and guiding significance for the engineering construction of similar geological environment conditions in the loess landslide area of Tianshui City.