双排桩土拱效应及嵌固段受力特性研究

发布时间：2018-04-11 06:29

本文选题：双排桩 + 土拱效应　；参考：《重庆大学》2014年博士论文

【摘要】：双排桩作为一种以横向受荷为主的支挡结构由于其具有抗滑能力强、抗侧移刚度大、结构受力合理、节约建筑用地、施工便捷等突出优点被广泛应用于滑坡地质灾害防治、边坡加固工程等领域中。尽管抗滑桩的设计理念、计算理论、施工技术正不断得到发展，但由于岩土性质的复杂性，抗滑桩的设计和施工中涌现出一些新的问题，目前，双排桩土拱效应的形成机理以及其空间表现形式，嵌固段桩身与岩（土）体相互作用等问题仍有待进一步深入研究。鉴于此，论文依托“长江学者和创新团队发展计划：山区岩土工程（NO：IRT1045）”、国家自然科学基金“岩土支挡结构健康诊断仪的研制（NO：51027004）”、重庆市百名工程技术高端人才计划项目“悬臂式抗滑桩三维土拱效应及其动力灾变研究计划（NO：0218002432010）”以及重庆市科技攻关项目“基于三维土拱效应的桩锚支护结构关键技术研究与应用”（CSTC-2010AC0109）。通过现场调查，室内试验，数值模拟、室外试验和理论研究等手段，对双排桩土拱效应成拱机理及影响因素和基于Wieghardt地基模型对嵌固段桩身受力进行了深入研究，主要工作及研究结论： 1）在现场调查和总结相关文献的基础上，设计了悬臂单排桩室内模型试验，试验重点研究了悬臂桩桩周土内部的应力分布特征及桩周土拱效应的作用程度、作用范围，通过改变滑体含水量和悬臂桩桩长的方式研究了其对土拱效应的影响，并指出，随着含水量的增加，土拱效应的影响范围呈现出先增强后减弱的趋势，悬臂段桩长越长，起拱效应越明显。 2）在悬臂单排桩室内模型试验研究的基础上，设计了双排桩室内模型试验，按“矩形”和“梅花形”布置，研究了前、后排桩受力分配模式和相应的起拱效应，通过改变前后排桩桩排距的方式，研究桩排距、布桩方式对前后桩桩周土拱效应的变化影响并指出悬臂双排桩前后土拱效应呈现出中下部强、上部弱的表现形式，前排桩与后排桩相比，前排桩桩周土拱效应的形成具有一定的滞后性，并对考虑土拱效应的双排桩设计给出了桩排距的建议值。 3）通过对埋入式双排模型桩进行试验，对比分析了埋入式双排桩和悬臂式双排桩两种结构形式前、后桩周土的应力分布、前后桩内力及变形，发现埋入式双排桩前排桩桩周土拱效应表现较弱，并在试验研究的基础上，进而分析了悬臂双排桩前、后桩周土拱的形成及破坏过程，可将其分为局部受压阶段、形成阶段、稳定发展阶段、拱脚剪切破坏阶段四个阶段。 4）运用有限元分析程序ABAQUS对矩形布置和梅花形布置的悬臂双排桩进行了数值分析，取得了与室内试验大致相同的规律：前排桩与后排桩桩周土拱效应均随土体高度的增加呈先增强后减弱的规律。并探讨双排桩的桩排距、挡土板刚度，布桩方式，，埋置方式，连梁方式对前后桩桩间土拱效应的影响、前后排桩内力的影响。 5）引入wieghardt地基模型，通过理论推导建立了基于wieghardt地基模型的悬臂桩嵌固段受力计算方法。通过普通K法、三角级数法及已有嵌固段桩-岩接触应力试验监测资料与本文wieghardt地基模型法理论计算结果进行比较分析，指出对于抗滑桩桩身嵌固段嵌入完整或较完整的砂岩地基时，采用wieghardt地基模型进行弹性计算较为合理。
[Abstract]:In view of the complexity of the anti - slide pile , the design of the anti - slide pile and its spatial expression , the research and application of the three - dimensional soil arching effect of the double - row piles and the interaction between the pile body and the rock ( soil ) have been studied .

1 ) On the basis of field investigation and summary of relevant literatures , the paper designs the indoor model test of cantilever single row pile , and studies the influence of the stress distribution characteristics and the effect of soil arching effect on the soil arching effect . The influence of soil arching effect on soil arching effect is studied by changing the water content of the sliding body and the length of the cantilever pile .

2 ) Based on the model test of cantilever single - row pile , a double - row pile indoor model test is designed . According to the " rectangle " and " plum blossom - shaped " arrangement , the stress distribution mode and corresponding arching effect of the front and rear row piles are studied .

3 ) By testing the embedded double - row model pile , the stress distribution , the internal force and the deformation of the embedded double - row pile and the cantilever - type double - row pile are compared and analyzed . Based on the test research , the formation and failure process of the embedded double - row pile front and rear pile periphery soil arch are found , which can be divided into four stages of local compression stage , formation stage , stable development stage and arch - foot shear failure stage .

4 ) A numerical analysis of cantilever double - row piles with rectangular layout and plum blossom - shaped arrangement is carried out by using the finite element analysis program , which has the same rule as the indoor test . The effect of the pile spacing , the stiffness of the soil retaining plate , the pile mode , the buried mode and the continuous beam mode on the soil arching effect between the front and rear piles is discussed , and the influence of the inner force of the front and rear piles is discussed .

5 ) Based on the wieghardt foundation model , a method for calculating the stress of cantilever pile block based on wieghardt foundation model is established through theoretical derivation . The results are compared and analyzed by ordinary K method , trigonometric series method and existing embedded section pile - rock contact stress test data and wieghardt foundation model method . It is pointed out that the wieghardt foundation model is used to calculate the elastic calculation .

【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU473.1

【参考文献】