Application And Monitoring Analysis Of Pile Design Technology For Accumulational Landslide

In recent years,Micro pile as a new retaining structure applications in a wide range of landslide control in the southern area of Shaanxi Province.because of its small pile diameter,convenient construction,characteristics of flexible pile.However,the application time of the micro pile is not very long,so it has not formed a complete theoretical system and design method,which largely limits the popularization and application of the micro pile.Because of the special geographical environment in southern Shaanxi area and geological structure,the geological hazards in the area there are certain difficulties in governance,in the face of geological disasters in southern Shaanxi frequent phenomenon,in order to seek effective and economic security measures and further optimize the micro pile used in the process of system design theory,this paper mainly through the collection of 72 Shaanxi landslide engineering example,through the summary analysis,summed up the characteristics of regional landslide in southern Shaanxi,the applicability of the control measures and various factors selection measures of landslide impact;on this basis,through the summary of 24 with micro pile as the landslide engineering supporting means,summed up the characteristics and advantages of the micro pile compared to other landslide prevention and control measures of micro pile with the combination and design method and design parameters.Finally,through the field monitoring,the displacement deformation,the earth pressure and the pile stress are analyzed to reflect the working state and the supporting effect of the micro pile.The main conclusions include:(1)Southern Shaanxi landslide mainly in the landslide,accounting for 97.3%of the total,mostly in small scale landslides,accounting for 97.2%of the total,the overall stability is poor,greater harm.(2)According to the southern Shaanxi landslide,the main supporting form of retaining wall,pile and anti slide pile,the statistics were accounted for 36.1%,25%and 20.8%.The retaining wall is mainly applicable to the sliding body thickness is less than 5m,the stability is relatively good,the landslide thrust is less than 300kn/m and no groundwater development small scale soil landslide;micro pile is mainly applicable to the sliding body thickness is less than 10m,poor stability,less than the development of landslide thrust of small and medium scale landslide groundwater or 1000kn/m;anti slide pile for landslide the thickness is more than 10m,the landslide thrust is greater than 1000kn/m,or with multi-level sliding surfaces of large landslides.(3)In the slope with quincunx pile,and the pile layout linking beam width and thickness.The link beam is not less than 2D?3D,reasonable pile spacing pile embedded in continuous beam depth of not less than 2D.of the micro pile is 8D?10d,row spacing is 8D?10d;anchorage depth of not less than L/3 not less than 2m.and the practice shows that in the process of actual Grouting grouting quantity and calculation of grouting volume ratio of 1.5 to 2 between the best effect.(4)The monitoring data through the analysis of lateral earth pressure,lateral earth pressure coefficient was 0.95,significantly higher than that of static earth pressure,micro pile improves soil bearing capacity,control effect is obvious.The vertical soil pressure is obtained by monitoring data monitoring value conversion coefficient and the theoretical value of 2.91,providing reference for similar engineering calculation of the area.(5)Through the analysis of soil pressure in each row piles that in layout of three rows of piles under the condition of attack from the soil surface to the back surface of soil,the first row of pile by the landslide thrust,the second and third row times,combined with the existing conclusions,in the design of micro pile can be increased at the first row pile soil surface the diameter of the pile and reinforcement or reduce the pile spacing and pile back;soil surface can reduce or increase the reinforcement pile spacing,in the economy at the same time,to achieve the best treatment effect.(6)Through the pile stress data analysis,landslide,micro pile as a flexible material is curved,the equivalent pile subjected to bending moment M,the micro pile can offset part of earth pressure,so as to ensure the pile integrity and is safe.