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  本文關鍵詞：加筋地基承載力增強機理與設計應用研究　出處：《重慶大學》2013年博士論文　論文類型：學位論文

  更多相關文章： 加筋地基 筋土相互作用 滑移線 極限分析 極限承載力

【摘要】：加筋土技術以其顯著的技術經(jīng)濟效益，越來越廣泛的應用在公路、鐵道、市政、建筑等領域。加筋地基能有效的提高地基承載力和變形協(xié)調能力，減小沉降和不均勻沉降，但由于加筋地基筋土作用機理和承載力增強原理研究不足，理論研究遠遠滯后于工程實踐，使加筋地基設計技術缺乏理論支撐，設計方法目前仍處于經(jīng)驗階段，嚴重的制約其推廣使用。本文在前人研究的基礎上，在教育部長江學者和創(chuàng)新團隊發(fā)展計劃創(chuàng)新團隊“山區(qū)巖土工程”（IRT1045）項目的資助下，采用室內模型試驗、理論研究和數(shù)值分析等手段，全面研究了加筋地基土應力和筋帶應力變化規(guī)律、筋帶影響區(qū)滑移線形態(tài)特征、承載力極限值，建立了加筋地基承載力增量設計方法，為加筋地基設計提供理論指導。進行的主要研究工作如下： ①通過模型試驗重點研究了加筋地基破壞區(qū)內筋帶應力和地基應力，對比分析加筋地基和無筋地基承載力和沉降變形特征，揭示了地基內主動狀態(tài)區(qū)、過渡區(qū)、被動狀態(tài)區(qū)和被動區(qū)外錨固段筋帶應力變化規(guī)律、筋帶影響區(qū)內土應力變化規(guī)律，分析了筋帶對地基中對土應力的作用。 ②根據(jù)筋帶對地基土的作用規(guī)律，建立了加筋地基應力計算模型，，分析了地基內主動狀態(tài)區(qū)、過渡區(qū)、被動狀態(tài)區(qū)內土體剪應力變化，結合Mohr-Coulomb原理，采用應力分析法和幾何求解法獲得了應力解；采用數(shù)值模擬揭示了地基加筋后各區(qū)筋帶應力和土應力變化規(guī)律。 ③通過對無筋土地基滑移線理論的分析，結合筋土作用機理，建立了滑移線計算模型和滑移線方程，根據(jù)加筋地基各區(qū)邊界條件，獲得了筋帶影響區(qū)內的滑移線解和應力解，并揭示了筋帶在加筋地基中的形成了水平高應力帶。 ④根據(jù)加筋地基滑移線分析成果，構建了加筋地基靜力場和機動場；運用上限定理，求解筋帶影響區(qū)的能量耗散率，分別建立純粘土加筋地基和一般土加筋地基的虛功率方程，求解加筋地基承載力上限值；分別建立純粘土加筋地基和一般土加筋地基的靜力場方程，運用下限定理，求解加筋地基承載力下限值；通過分析上限值和下限值的差異，確定地基承載力極限值，并分析純粘土加筋地基和一般土加筋地基極限值的關系。 ⑤在現(xiàn)有加筋地基承載力設計方法的基礎上，根據(jù)加筋地基承載力極限分析理論，運用上限值和下限值求解加筋地基極限承載力增量，應用強度折剪系數(shù)和筋帶置換系數(shù)，求解加筋地基承載力增量設計值和筋帶強度設計值，建立加筋地基承載力增量設計法。并以天江鼎城Ⅰ期雅園小區(qū)填土地基為例，將極限分析法設計的加筋地基承載力增量與實際靜載試驗成果進行對比，驗證承載力增量極限分析法的可靠性。
[Abstract]:Reinforced soil technology with its remarkable technical and economic benefits, more and more widely used in highway, railway, municipal, construction and other fields. The reinforced foundation can effectively improve the foundation bearing capacity and deformation coordination capacity, reducing settlement and uneven settlement, but due to insufficient research in principle of reinforcement mechanism and bearing capacity of reinforced foundation reinforced soil, theoretical study is far behind engineering practice, the design technology of reinforced foundation lack of theoretical support, the design method is still in the stage of experience, seriously restricting its application. Based on the previous research, the Ministry of education Changjiang Scholars and innovative research team plan innovation team "development in the mountainous areas of geotechnical engineering" (IRT1045) project funded by the indoor model test, theory research and numerical analysis, a comprehensive study of the reinforced soil stress and reinforcement stress variation affected zone of slip line shape band Based on the characteristics and ultimate bearing capacity, the incremental design method of reinforced foundation is established, which provides theoretical guidance for the design of reinforced foundation.
Through the model test on reinforced foundation failure zone reinforcement stress and foundation, comparative analysis of reinforced foundation and reinforced foundation bearing capacity and deformation characteristics, reveals the foundation of active zone, transition zone, passive and passive zones outside the anchorage reinforcement stress variation that band in the influence area of soil stress variation analysis of reinforcement on stress of soil foundation in the role.
According to the rules of the foundation soil reinforcement, a stress calculation model of reinforced foundation, analyzes the foundation of active zone, transition zone, passive area soil shear stress change, combined with the principle of the Mohr-Coulomb, using the stress analysis method and geometry method to obtain the stress solution; numerical simulation reveals the foundation reinforced District reinforcement stress and soil stress variation.
Through the analysis of non reinforced foundation slip line theory, combined with the soil reinforcement mechanism, calculation model and slip line equation of slip line is established according to the boundary condition of reinforced foundation, the reinforcement effect of slip line in solution and the solution of stress, and reveals the reinforcement in the reinforced foundation the formation of the high level of stress.
According to the analysis results of reinforced foundation slip line, construction of reinforced foundation static field and motor field; using upper bound theorem, the energy dissipation rate for impact zone band, established a virtual power equation of pure clay reinforced foundation and reinforced the general soil foundation, solve the reinforced foundation bearing capacity limit are established; the static field equations of pure clay reinforced foundation and reinforced the general soil foundation, using the lower bound theorem for reinforcement of foundation bearing capacity limit; through the analysis of the upper limit and the lower limit value differences, to determine the bearing capacity limit, and analyze the relationship between the pure clay reinforced foundation and soil foundation reinforced with a limit value.
The basic design method of bearing in existing reinforced foundation, according to the theoretical analysis of bearing capacity limit of reinforced foundation, the upper limit and lower limit increment of bearing capacity for solving the limit of reinforced foundation, application of strength reduction factor and reinforcement coefficient of displacement, solving the reinforced foundation to increase the design value and the reinforcement strength design value of bearing the force bearing capacity, establish incremental design method of reinforced foundation. And the day Jiang Dingcheng stage I Nga District fill foundation as an example, the design method of limit analysis of reinforced foundation bearing capacity and the actual incremental static loading test results were compared, the reliability analysis method to increase the ultimate bearing capacity verification.

【學位授予單位】：重慶大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU470

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本文編號：1399824