【作者】 孙厚超；

【导师】 李山；

【作者基本信息】 成都理工大学 ， 防灾减灾工程及防护工程， 2007， 硕士

【摘要】 滑坡地质灾害防治措施中，抗滑桩是常见的工程措施之一。一般，它是通过增大桩身截面积来增加桩的强度和刚度，从而抵抗滑坡推力。大截面抗滑桩在实践中存在很多问题，如：滑坡施工场地往往不便于大型机械设备进场，实践中只好多采用人工挖孔的方式；工程土方量大，施工干扰大，对临滑状态的滑坡抢险不利；施工效率低、成本高、安全性差等等。采用小直径钻孔施工的微型组合桩结构是一种新型抗滑桩，与大截面桩相比具有许多优点。但是，由于目前还无设计规范，特别是对如何考虑桩和土的共同承载作用尚未有明确认识，所以设计应用中还存在一些理论问题亟待解决。本文主要采用数值分析的方法，结合工程实例对微型组合桩的桩土相互作用机理进行研究分析，期望得出一些可供指导设计计算的思路与方法。在研究分析中我们得出：微型组合桩在滑坡推力的作用下，桩体受力以压应力为主：压顶梁在发生变形时，会引起应力集中，尤其在右桩与压顶梁连接部位；桩土作用的一般规律是：随着微型组合桩的排距在一定范围内增大，桩的变形相应减小，应力减小幅度不大，但排距超过一定范围，将会使结构失效；随着微型桩的锚固深度的增加，桩顶的位移在减小；桩体应力呈现增大、减小交替规律，变化的差值不大，但当锚固深度增大到一定时，再增加深度对微型组合桩应力、变形影响甚小。基于微型组合桩的受力、变形分析，微型桩受力以压应力为主，在滑坡治理设计上，引入承受压力的网状结构树根桩的设计方法，将“平20”井滑坡设计参数代入计算，满足强度和稳定性要求。并运用有限元强度折减法对治理后滑坡进行稳定性评价，稳定安全系数为1.22，满足了设计要求。微型组合桩结构治理滑坡在岩土工程中仍然处于尝试阶段，需要结合物理模拟、现场监测等手段来进一步提高分析结果的可靠度，从而寻找出经济合理的设计方法。更多还原

【Abstract】 Anti-slide piles are often used to preventing geo-hazard of landslide, They canwithstand landslide thrust by means of improve pile’s stiffness with large section.There are many questions for the large section pile. When it is not easy for big machines togo into the construction fields, artificial digging piles have to be applied. Earthwork andconstruction interference are terrible and it is disadvantaged for landslide fighting in the criticalsituation. Lower efficiency of construction, higher cost and lower security are some questions.The mini-pile in which only small diameter drill construction is applied is a newanti-slide pile. There are more advantages than the large section pile. Because of shorting ofdesign code, specially shorting of explicit conclusion for the interaction between mini-piles andearth, there are some theory questions which are needed to be solved in design. In the articlethe interaction between mini-piles and earth is analyzed by means of numericalsimulation with engineering cases so as to get some thought and methods which isused to design and calculate.It is showed that when mini-piles is trusted by landslide, compression stress ismain stress in the piles, and that stress will concentrate when beam deform, especiallyat the intersection of right piles and beam. The relations between piles and earthusually are that the deformation become smaller and stress changes little whendistance between piles and piles become bigger in some distance, but it will becollapsed when distance is exceed certain number. Displacement of piles’ topbecomes small and piles’ stress becomes big when anchorage depth becomes bigger.When anchorage depth is a number, changes of stress and displacement are little.Based on the analysis on stress and deformation of mini-piles, compression stressof the piles is main stress. Net shape tree root as a pile which bears compressionstress is used in the design of landslide prevention. Stress and stability can apply forit when the parameters of PING 20 landslide is cited. Landslide protected is appraisedby strength reduction finite element method, and stability coefficient is 1.22.Landslide prediction with mini-piles in the engineering begins lately. It needsto be improved credit number with physical modeling and monitoring to findeconomic and suitable design methods.更多还原