Study On Load Transfer Characteristics Of Multi Soil Arching Effect Of Double Piles

Because of resistance to large scale landslide thrust,less displacement of pile top and more reasonable distribution of pile body stress,Double piles(combined anti-sliding piles)are being used to control large scale slide gradually.Although double piles have a good retaining effect,its retaining mechanism is less now,so the system analysis the retaining mechanism of double piles can contribute to the application of double piles.Soil arching effect to be an important part of retaining mechanism,whose systematic understanding can improve the cognition the retaining mechanism of double piles.Based on above these,this paper analysis the mechanism of soil arching effect from theory analysis,model simulation,physical test rely on National Natural Science of china(51408086),Graduate Innovation Fund of Chongqing(CYS14165).The mainly work of the paper are showed as follows:(1)Establish calculation model of multi soil arching effectReference to the traditional calculation method,the types of soil arching effect of front and rear piles are analyzed and divided into different groups(frictional arch and end bearing arch)based on their mechanism;for every type of soil arching effect,the stress calculation model,reasonable arch line,damage mechanism of arch foot are conducted to obtain the ultimate bearing load and rise of arch line of every types of soil arching effect.Based on above calculation model,the calculation formula of reasonable pile space,reasonable space of front and rear pile,the distribution of stress on front and rear pile and the resistance of soil in front of front pile are conducted.These formulas are verified by examples.(2)Establish simulation model of multi soil arching effectIn order to simulate the multi soil arching effect more scientific and reasonable,the perspectives of macro and micro are introduced to simulation multi soil arching effect.From macroscopic perspective,the FLAC software based on FDM theory are used to analysis the development process of multi soil arching effect of double piles,and some typical influence factors(cohesive,friction,elastic,passion,pile space and the interface mechanism)on multi soil arching effect.From microscopic perspective,the PFC software based on DEM theory are used to analysis the development process of multi soil arching effect,and some typical factors(friction of soil balls,porosity,and pile space)on multi soil arching effect.(3)physical test on multi soil arching effectAccording to previous researches on multi soil arching effect,three dimensional geo mechanical model test platform are established to monitor the soil pressure in key position where soil pressure senor are assigned in these places.Through the soil pressure senor placed on the back of front pile and rear piles to monitor the change trend and the difference,and the development process and difference law are analyzed.Through the soil pressure senor placed around on piles to monitor the exist of multi soil arching effect and their develop trend.The retaining effect are also analyzed at the same time.