Calculation Theory And Design Method Research On H Type Of Anti-sliding Piles

High mountain mainly located in West China with complex geologicalcondition and it easily induced Geological hazards, such as landslides. In recent years,infrastructure construction increased the vulnerability of geological environment inthis area. According to the engineering geological characteristics, this paper put the htype of anti-sliding piles as core research and make it as a new structure for landslideand high slope control. From the mechanical characteristics and constructionsuitability of h type of anti-sliding piles, this article puts forward the calculationmethod of the new structure, and through numerical simulation, large structure modeltest, analysis and confirm its working mechanism and structure performance. Themain research and conclusions are listed as follows:1、This paper make research of the stress mechanism and structure character of htype of anti-sliding piles. As ths statically indeterminate structure and spatial structure,h type of anti-sliding piles is better than ordinary anti-slide pile which belongs to thestatic structure in the structure performance and work form. In the changing the load,h type of anti-sliding piles could automatically adjust the structural internal force andhave collaborative work ability. When the former pile and the back pile resistthrusting force together, we could distribute internal force, moment, shear between theformer pile, the back pile and the beam by adjusting structure geometry size in orderto play combined structure performance in greatest degree.2、This paper then analyze the Geological suitability of h type of anti-slidingpiles. According to the regional environmental geological characteristics andstructural characteristics, puts forward its engineering environment conditions. h typeof anti-sliding piles is suitable for all kinds of medium and large landslides and thehigh slope, especially suitable for landslide thrust greater than2000kN/m and slidestrata. Compared with the current of the most widely used prestress anchored anti-slide pile, h type of anti-sliding piles avoid to its problems such as the stressrelaxation, rust and limited conditions use. The cantilever structure characteristics hasstrong " reduce slope" function, which is suitable for cutting slope block project.3、Explore to the structure calculation method of h type of anti-sliding piles. Foraccurate structure calculation, we not only need to determine thrusting force formbetween the former pile and the back pile, but also need to make sure the thrustingforce distribution situation. In this paper, we have make sure all thrusting force of thestructure by establishing calculation model, then provides calculating load distributionstate of h type of anti-sliding piles. Based on the numerical method of structuralmechanics, we get the analytical solution for upper structure, and get the analyticalsolution for bottom structure by P-y curve method or elastic (rigid) pile method.4、Based on the general design principle, puts forward the design requirementand design content of the h type of anti-sliding piles, and established the basic designprocess. Then research the bearing capacity of structure design, include normalsection tension design and checking, and oblique section design, and establish thecorresponding calculation steps and algorithm. By structure design principle andstructural characteristics, we study the related requirements of reinforcement design.5、Through numerical simulation of h type of anti-sliding piles by finite elementmodel, we research the structural deformation law and stress distribution state, thenanalyze the parameter on influence analysis, come to some conclusion:(1) When rowdistances is2.5d≤Z≤4.5d, the resistance to deformation ability of the former pile andthe back pile are best and the moments of them are also in superior condition. Itsuggest us to selected row distances in this interval for engineering design.(2) Toproduce effective soil arching effect, the spacing between piles is2.5b≤L≤3.5b, thistime engineering technology economic level is best. But when4b≤L, soil archingeffect will drop, only rely on friction between the soil to provide resistance.(3) Withincrease of the soil compression modulus ES, the bending moments of the back pilerise, and the bending moments of the former pile decrease. Improving the soilmodulus, can make it more fully transmit pressure between former pile and back pile,and optimize h type of anti-sliding piles force performance.(4) The computationalresults show that keep the structure rigid connection is very important. Not only caneffectively avoid large displacement, but also can realize coordination of the positivebending moment between former pile and back pile, and decrease the negative bending moment in bottom structure.(5) The change of the cantilever lengthproportion impact on performance significantly for h type of anti-sliding piles,when0.5-0.67, Structure has better performance.6、Through the portal double row piles and h type of anti-slide piles structuremodel test, research structural internal force distribution and deformation law andStress-strain state in different load conditions, come to some conclusion:(1) The portaldouble row piles and h type of anti-slide piles as the combined structures, haveperformance advantages in rigidity, The structural deformation are small and basicallythe same displacement between the former pile and the back pile which has superiorcollaborative ability.(2) Measured data show that the former pile and the back pilealways in alternating stress state. For bottom structure, they appear maximum stressnear the slide surface, which are weak links. Due to the different of structure size andload distribution form, the placement and numerical of maximum stress have a certaineffect.(3) In different load distribution, h type of anti-slide piles internal force state isdifference. Triangular load will produce more stress value in the back pile thanuniformly distributed load, and triangular load will make maximum stress appearednear the slide surface for the former pile than uniformly distributed load.(4) Thestress-strain state can be obvious divided into three process corresponding to differentperformance characteristics and are directly related to cracking with h type ofanti-slide piles. The structure cracking of h type of anti-slide piles has obviousbending component characteristics.(5) The former pile and the back pile have largerbending moments under fixed supporting than under free supporting. For slide surfacedisplacement, it is smaller under fixed supporting than under free supporting.7、This paper research the construction technology and construction process of htype of anti-slide piles, and discuss some key construction technology. Then establisha preliminary construction process for h type of anti-slide piles in order to improve itsengineering application.8、Based on the Chongqing dapin landslide project, compared with two designsfrom stress state, slope stability, pile stress and engineering cost to effective provethat h type of anti-slide piles have technical and economic advantages.