【作者】 易朋莹；

【导师】 张永兴；

【作者基本信息】 重庆大学 ， 岩土工程， 2013， 博士

【摘要】 加筋土技术以其显著的技术经济效益，越来越广泛的应用在公路、铁道、市政、建筑等领域。加筋地基能有效的提高地基承载力和变形协调能力，减小沉降和不均匀沉降，但由于加筋地基筋土作用机理和承载力增强原理研究不足，理论研究远远滞后于工程实践，使加筋地基设计技术缺乏理论支撑，设计方法目前仍处于经验阶段，严重的制约其推广使用。本文在前人研究的基础上，在教育部长江学者和创新团队发展计划创新团队“山区岩土工程”（IRT1045）项目的资助下，采用室内模型试验、理论研究和数值分析等手段，全面研究了加筋地基土应力和筋带应力变化规律、筋带影响区滑移线形态特征、承载力极限值，建立了加筋地基承载力增量设计方法，为加筋地基设计提供理论指导。进行的主要研究工作如下：①通过模型试验重点研究了加筋地基破坏区内筋带应力和地基应力，对比分析加筋地基和无筋地基承载力和沉降变形特征，揭示了地基内主动状态区、过渡区、被动状态区和被动区外锚固段筋带应力变化规律、筋带影响区内土应力变化规律，分析了筋带对地基中对土应力的作用。②根据筋带对地基土的作用规律，建立了加筋地基应力计算模型，分析了地基内主动状态区、过渡区、被动状态区内土体剪应力变化，结合Mohr-Coulomb原理，采用应力分析法和几何求解法获得了应力解；采用数值模拟揭示了地基加筋后各区筋带应力和土应力变化规律。③通过对无筋土地基滑移线理论的分析，结合筋土作用机理，建立了滑移线计算模型和滑移线方程，根据加筋地基各区边界条件，获得了筋带影响区内的滑移线解和应力解，并揭示了筋带在加筋地基中的形成了水平高应力带。④根据加筋地基滑移线分析成果，构建了加筋地基静力场和机动场；运用上限定理，求解筋带影响区的能量耗散率，分别建立纯粘土加筋地基和一般土加筋地基的虚功率方程，求解加筋地基承载力上限值；分别建立纯粘土加筋地基和一般土加筋地基的静力场方程，运用下限定理，求解加筋地基承载力下限值；通过分析上限值和下限值的差异，确定地基承载力极限值，并分析纯粘土加筋地基和一般土加筋地基极限值的关系。⑤在现有加筋地基承载力设计方法的基础上，根据加筋地基承载力极限分析理论，运用上限值和下限值求解加筋地基极限承载力增量，应用强度折剪系数和筋带置换系数，求解加筋地基承载力增量设计值和筋带强度设计值，建立加筋地基承载力增量设计法。并以天江鼎城Ⅰ期雅园小区填土地基为例，将极限分析法设计的加筋地基承载力增量与实际静载试验成果进行对比，验证承载力增量极限分析法的可靠性。更多还原

【Abstract】 Reinforced foundation technology has gained more and more popularity inhighway, railway, municipal, construction and other fields for its remarkable technicaland economic benefits. Reinforced foundation can effectively improve the foundationbearing capacity and deformation coordination, and reduce settlement and unevensettlement.Because research on the mechanism of reinforced foundation and bearingcapacity enhancement principle is insufficient, theoretical research is far behind theengineering practice, lacking the support of theoretical design method the design ofreinforced technology is still in the stage of experience at present, severely restricting itsuse. The paper is a part of the development plan project Mountainous Area ofGeotechnical Engineering (IRT1045), affiliated the ministry of education Yangtze Riverscholars and innovation team. On the basis of previous research, the paper includes thetheoretical research and numerical analysis methods, the comprehensive research ofreinforced foundation soil stress and stress change rule, ribbon affected zone slip lineshape characteristic, the bearing capacity and limit analysis incremental design methodis established and provide theoretical guidance for reinforcement of foundation design,the main research work are as follows:①The model test research is mainly focused on the reinforced ribbon stress andfoundation stress of destruction of reinforced area. Through analysis of reinforced andunreinforced foundation bearing capacity and settlement deformation characteristics,foundation is mainly studied in active status area, transition area, passive status area andpassive zone anchorage stress change rule section of the ribbon, the ribbon influencezone soil stress change rule, revealing the ribbon of soil stress in the foundation.②According to the ribbon to the effect of the foundation soil, the reinforcedfoundation stress calculation model was established, analyzed the foundation within theactive state area, transition area, passive state area soil shear stress change, combinedwith the Mohr-Coulomb theory, using stress analysis method and geometry method toobtain the stress solution; The numerical simulation reveals ribbon stress and soil stresschange rule of reinforced foundation.③Through analysis of unreinforced soil slip line theory, combining with thereinforced soil mechanism, establish the slip line calculation model, according to thereinforcement of foundation district boundary conditions, obtain the ribbon slip line solution and stress solution of impact area, and reveals the ribbon in the reinforcedfoundation has formed a high stress zone.④Based on the results of reinforced foundation slip line analysis and constructsthe reinforced foundation static and mobile fields; Limit theorem is used to solve theribbon affects the energy dissipation rate, establish the virtual power equation of pureclay reinforced foundation and the general soil reinforced foundation, solve the upperlimit value of bearing capacity of reinforced foundation; establish the static fieldequation of pure clay reinforced foundation and the general soil reinforced foundation,solve the lower limit value of bearing capacity of reinforced foundation; Through theanalysis of the difference of upper limit and lower limit, and determine the limit valueof upper limit bearing capacity, and analyzes the pure clay reinforced foundation and thegeneral soil reinforced foundation limit value.⑤Based on the existing design method of reinforced foundation bearing capacity,according to the theory of limit analysis of reinforced, using upper limit and lower limitvalue to solve the ultimate bearing capacity increment of reinforced, used strength shearcoefficient and ribbon displacement coefficient, to solve the incremental design method.Taking the first-stage project of Tian Jiang Ding Cheng plot fill soil foundation as ademonstration, the Increment of foundation bearing capacity which designed by limitanalysis method and the actual bearing capacity of reinforced static load test results fitwell with numerical results, verify the reliability of limit analysis.更多还原