Research On The Design System Of The Micropile Reinforcing Landslide In Accumulation Layer

As a new type of micro pile reinforcement retaining structure,is generally between 100-300mm small diameter anti sliding pile.This kind of small diameter pile branch with the traditional retaining structure compared with non excavation construction,the advantages of smaller,flexible layout location,fast construction speed and economic good perturbation of the soil which is around the pile,the shallow layer sediments landslide is applied more and more widely.But the theoretical research of micro pile landslide reinforcement lags far behind the practical engineering application which is still not formed a than systematic micro pile calculation theory and design method,to a large extent restricts the application and popularization of micro pile.In view of this,in order to draw the reinforcement mechanism and design technology of micro pile,this paper is based on the similar model tests in the laboratory,for shallow landslide,the following research work and conclusions are mainly drawn::1)According to the elastic plastic theory,the study of the soil pile row transmission mechanism,by the pile-soil deformation compatibility principle,the analysis of micro pile reinforcement mechanism,comprehensive comparison,recommended the use of the transfer coefficient method to detennine the landslide thrust,combined with common anti slide pile calculation method,cantilever pile method and follow the example of micro pile internal force calculation,bearing capacity and flexural bearing capacity and shear capacity determined by the2)Through the data collection and collation,in accordance with the principle of calculation and design method,the design system of micro pile into the limit equilibrium method,curve method,equivalent section method,software method,the equivalent bending stiffness method and nonuniform coefficient method.And gain a comprehensive comparative study of the advantages and disadvantages from the applicable conditions angles.Based on the completed model test and the comparison of different test conditions,three kinds of failure modes of the micro pile group are determined,which are the overall failure,the single pile failure and the local failure.3)With the elastic plasticity theory and model test result analysis,summarizes the design principle of micro pile,namely reasonable pile spacing should be 8～12d,row spacing should be an interval 10d,this range not only effectively exert their anti slide force can best play between piles soil arching effect;the pile anchor depth to 1/3-2/5 pile length best;Pile soil around Dense real-time,pile group should adopt the arrangement of the layout of soil is loose,pile group should adopt the plum shaped arrangement;group pile top shall be provided with coupling beams,both limiting pile top displacement and the force of pile more uniform and plump;on the basis of the actual rainfall,set the corresponding drainage system.4)To mian county soil closed shop in hangzhong township zhuo pen village of the The Loess Landslide for example,in the analysis of engineering geological characteristics,deformation characteristics,formation mechanism and influencing factors based on design scheme:micro pile.And in safety,economy,applicability,environmental Influence of fuzzy hierarchy construction period and factor analysis method(AHP)using to design has carried on the comprehensive evaluation and comparison,finally according to the maximum membership degree principle sorted that the optimal solution for the use of single root pile treating landslide.