Analysis Of Work Mechanism Of Anti-slide Micro-piles And Optimal Design

Anti-slide piles are often used to preventing landslide as an important measure at present,they can increase the stiffness and strength of the pile by incraeasing shaft cross-section,so as to achieve the purpose of anti-sliding.With the development of the science and technology,the study about the way of landslide consolidation is developing to complex,lightened, miniaturized and mechanical constuction.Therefore, micro-piles arise.However,the theories of anti-sliding,design and project evaluation about micro-piles are still in the process of exploring so it has important theoretical and practical value to study it .This article has researched the geological conditions and stability of the White Cave landslide by studying present domestic and international research on micro-pile and the example of thecontrol project-White Cave landslide.Combined with the Specificity of this project and based on the micro-pile,it presents the design of the landslide control and also discusses the common issues about the landslide control by micro-pile such as choosing the reasonable type,layout,sapcing and anchorage length of micro-pile so on so forth. Aiming at the design and according to the model established by data analysis software MIDAS/GTS,this article analyzes the anti-sliding mechanism of the micro-pile and discusses the influence on Slope Stability by spacing and anchorage depth of micro-pile.Also it explains the importance of the contact beam in the micro combine pile.The details and result are as below:(1)The model of data analysis established by MIDAS/GTS soft basing on the consolidation of the left slope analyzes the anti-sliding mechanism of the micro–pile. According the analysis, when the micro-pile is consolidating the slope, maximum horizontal displacement occurs in steps at the pile. Maximum plastic deformation of the slope is after the step edge of the slope with micro-pile, it is difficult to form through plane. The maximum shear and bending moment the Micro-piles bearing occurs in the vicinity of sliding surface, a damaging mode of micro-piles in the vicinity of the slip surface combined shear and bending. When the micro-pile is consolidating the slope, the axial force it bearing is pressure which is concentrated in the anchorage section.When the top of the pile is moving,the pile will be pulled. The article shows that when the pile sapcing of 1.2m, the horizontal displacemen of slope reaches 4cm, the pile by the tension as 13.26kN.The landslide thrust it bears which is trapezoidal distribution and the resistance is rectangular distribution.Force model by studying the mechanism laid the foundation for the establishment of micro-pile theoretical of design calculation.(2)Getting from the influence on the stability of the slope by the pile distance,the pile distance has the influence on the change of the slope stability,when the distance ness than 0.8m,the slope failure. When the distance is not equal to 1m,the maximum shear, and bending moment which appears near the top of the pile,the maximum shear and bending moment of contact piles increases and damages easily.When 0.9m <L <1.1m, the pile increasing pressure, and the pile is only under pressure; when L <0.9m or L> 1.1m, Top of the pile will be tension, and the reason is the pile top displacement increasing.(3)Getting from discussing about the issues of the anchorage depth, when the anchorage depth is reaching 1/3~1/2 of pile length, the slope stability will not have big change. When the anchoring depth is less than 1 / 3 of the pile length, the stability of landslide decreases with the decrease of the anchoring depth; when larger anchoring depth, the axial force the pile bearing increases gradually, the specific values should be select a reasonable value under the porce of piles in the the range of pile length 1 / 2 to 1 / 3.(4)According to the analysis on comparison of the slope stability and micro-pile force under the two kinds of situations-with contact beam and without contact beam, the maximum shear and bending moment whit contact beam is small than without contact beam.With the role of contact beam, the pressure on top of the pile reduces and the contact beam under tension.If there is not contact beam, the top of the pile only under pressure, and bending deformation.The under tension,and the horizontal beam under pressure, the value of the axial force on verdical beam is far greater than horizontal beam, play a guiding role in the design. (5)According to the result of the discussion, the design is optimized and getting the most suitable design for this project-pile distance L=1.0cm and the anchorage length H=6m.Comparing the stability before and after the slope consolidation, the maximum displacement reduces and location of the maximum shear changes.It can explain the feasibility of the programmer of micro-pile consolidation.The slope control project of the micro-pile is still in trial stage. What should be done is to verify the anti-sliding mechanism and calculating method proposed by different scholars by the numerical and physical simulation test.The most important thing is using monitoring results completed by big testing and project to analyze the anti-sliding mechanism and to get one complete series of micro-pile design and specifications.