【作者】 胡俊强；

【导师】 陈建功；

【作者基本信息】 重庆大学 ， 土木工程， 2014， 博士

【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。更多还原

【Abstract】 Double-row piles, as a predominant structure to resist horizontal sliding, has beenwidely used in landslide prevention, slope engineering reinforcement and other fieldsbecause of its significant advantages, such as its strong anti-sliding ability, large lateralstiffness, reasonable structure, conservation of building land and constructionconvenience, etc. Although the design concept, calculation theory and constructiontechnology of anti-sliding pile are developing continuously, in the design andconstruction of anti-slide pile, some new problems emerge because of the complexity ofgeotechnical properties. At present, it is necessary to do further research to study theformation mechanism and space form of soil arching effect of double-row piles and theinteraction of anchored segment of anti-sliding pile and rock or soil. This dissertation issupported by the program ‘Yangtze scholars and innovative research team: mountainousgeotechnical engineering(No.IRT1045)’; the project ‘Development of HealthyDiagnosis Instrument for Geotechnical Retaining Structure(No.51027004)’ of NationalNatural Science Foundation; the project ‘Plan of three-dimension soil arch effect andresearch on dynamic disaster of cantilever anti-slide piles(NO.0218002432010)’ ofHundreds of Engineering Technique Talents Project of Chongqing; the program ‘theresearch and application of key technology of pile anchor retaining structure based onthree-dimension soil arching effect(CSTC.2010AC0109)’ of Chongqing scientific andtechnological projects. The author carried out systematic studies on the formingmechanism and influential factors of soil arching effect of double-row piles, also theforce of anchored segment of piles based on wieghardt elastic foundation model byimplementing field investigation, laboratory test, numerical simulation, outdoorexperiments theoretical research and other technical methods. The main work andconclusion of this dissertation are listed as below:1) Based on the field investigation and summarize of related literature, an indoorcantilever one-row piles model test was designed to study the internal stress distributioncharacteristics of the piles and the degree and scope of arching effect of soil around thepiles. The author studied how the water percentage of landslide mass and the length ofcantilever pile affect the soil arching effect and point out that with the increasing levelof water percentage, the range of soil arching effect enhance, followed by theweakening trend. The longer the pile’s cantilever segement is, the more obvious soil arching effect is.2) Based on the indoor cantilever one-row pile model tests, an indoor double-rowpiles model test by arranging with rectangle and quincunx was designed to study theinternal force distribution pattern of front row piles and back row piles and the formingmechanism of soil arching effect. The author studied how layout of piles and pile rowdistance affect the change rule of soil arching effect with front row piles and back rowpiles and the internal force distribution pattern of front row piles and back row piles,and pointed out that the soil arching effect of cantilever double-row piles performs astrong effect on the middle and bottom of the soil, performs a weak effect performanceon the upper layer of the soil. Compared with the back row piles, the forming of soilarching effect of the front row piles has certain hysteresis. The author also finds that thedesign value of the pile row distance of double-row piles was suggested by consideringthe soil arching effect.3) Based on the indoor double-row piles model tests, an indoor embededdouble-row piles model test is also designed to compare with the cantilever double-rowpiles about the results of the stress distribution of the soil, the internal force distributionpattern and deformation of front row piles and back row piles and the formingmechanism of soil arching effect. The author found that the performance of soil archingeffect of the front row piles is weaker in the embedded double-row piles test. Theformation and destruction of soil arching effect which is analyzed on the basis ofexperimental study could be divided into four stages: local compression stage, formingstage, stable and development stage and failure stage.4) Based on the indoor double-row piles model tests, double-row piles byarranging with rectangle and quincunx have been carried on the numerical analysis byusing the finite element program ABAQUS. Same rules are acquired approximately. It isdiscussed that the influence of the internal force distribution pattern of front row pilesand back row piles and the forming mechanism of soil arching effect with changing thepile row distance, layout of piles, embedment method, plate stiffness and coupling beamwith front row piles and back row piles.5) The wieghardt elastic foundation model is introduced in this dissertation, acalculation method of ground resisting force acted on build-in zone of cantilever piles isderivated based on the wieghardt foundation model. By comparing the testing results ofcompression stress which acts on the contact surface between pile and ground with thecalculation value which are calculated with K method, trigonometric series method and the theoretical derivation method based on wieghardt foundation model, the authoranalyzes the results and points out that it is reasonable to use the method based onwieghardt elastic foundation model when the socketed segment is embedded in relativeintegrity or integrity sandstone foundation.更多还原