本文關鍵詞： 高速公路拓寬工程 泡沫輕質土 彈塑性有限元分析 軟土地基 硬殼層效應 有限元強度折減 塑性區(qū)貫通　出處：《河北工業(yè)大學》2015年碩士論文　論文類型：學位論文

【摘要】：針對東南沿海地區(qū)軟土地基上的高速公路拓寬工程,通過分析其病害機理及不協(xié)調變形的控制手段,結合目前廣泛推廣采用的輕質填料,提出應轉變處理角度:從提高拓寬路基下軟基的承載力或固結度轉變?yōu)榻档推渖细哺郊雍奢d,以期通過控制拓寬路基填料的性質來減小對軟基的處理強度并合理優(yōu)化擋墻結構。本文以唐津高速擴建工程為研究載體,結合現(xiàn)場對泡沫輕質土拓寬路基的土壓力實際監(jiān)測與有限元數(shù)值模擬分析,從以下幾方面進行了重點研究:首先,對泡沫輕質土的主要物理力學指標特性及其工程應用機理進行總結分析,并結合有效應力原理及硬殼層效應對軟基固結沉降的控制措施進行原理性探究,且重點研究了泡沫輕質土用于軟基上路基拓寬的力學機理,明確指出土工合成材料用于板體性輕質土拓寬銜接時應著重考慮的因素。其次,從巖土材料產(chǎn)生塑性變形的內在機制出發(fā)研究其區(qū)別于金屬材料的彈塑性理論,并根據(jù)泡沫輕質土的力學特性指出其對DP理想彈塑性模型的適用性。結合路基拓寬的施工階段影響及輕質土本身的施工特點,利用舊路基及地基自重荷載產(chǎn)生的初應力場施加及舊路邊坡開挖、輕質土分層澆筑的單元生死技術,對輕質土拓寬路基在施工過程中及不同拓寬斷面尺寸下的應力響應進行非線性結構分析,提出了輕質土板體在澆筑層間及基底處類似于剛性基礎的傳力機制,并結合硬殼層效應及輕質土荷載分布特點對拓寬路基不同位置處的位移發(fā)展趨勢進行探索,以明確輕質土拓寬路基的受力薄弱區(qū)及位移發(fā)展集中區(qū)。最后,通過強度折減原理,對輕質土拓寬路基的整體穩(wěn)定性進行分析,從輕質土的材料參數(shù)、軟基的抗剪強度、硬殼層三個因素探究其對拓寬后路基整體的塑性區(qū)貫通、側向位移發(fā)展的影響,并重點對比研究了高窄型與低寬型拓寬路基的塑性區(qū)形成特點及失穩(wěn)破壞機理,從而指導拓寬時輕質土材料設計參數(shù)的調整、土工材料銜接處理的重要位置確定及軟基的針對性加固。
[Abstract]:Aiming at the expressway widening project on soft soil foundation in southeast coastal area, through analyzing the disease mechanism and the control means of uncoordinated deformation, combining with the light packing widely used at present, It is proposed that the angle of treatment should be changed: from increasing the bearing capacity or consolidation degree of soft foundation under widening roadbed to reducing the additional load on top of it, In order to reduce the treatment strength of soft foundation and optimize the structure of retaining wall by controlling the property of widening the filling of roadbed, this paper takes Tangjin high-speed expansion project as the research carrier, Combined with the field monitoring and finite element numerical simulation analysis of the earth pressure of the foamed lightweight soil widening roadbed, the following aspects are emphatically studied: first of all, The main physical and mechanical properties of foamed light soil and its engineering application mechanism are summarized and analyzed, and the control measures of consolidation settlement of soft foundation are studied by combining the effective stress principle and the effect of hard shell layer. The mechanical mechanism of foam lightweight soil used for roadbed widening on soft foundation is emphatically studied, and the factors that should be considered when geosynthetics are used in widening of plate lightweight soil are pointed out. Secondly, Based on the inherent mechanism of plastic deformation of geotechnical materials, the elastic-plastic theory, which is different from metal materials, is studied. According to the mechanical characteristics of foamed lightweight soil, the applicability of this model to DP ideal elastoplastic model is pointed out, which is combined with the influence of roadbed widening in construction stage and the construction characteristics of lightweight soil itself. The unit life and death technique is used to apply the initial stress field caused by the old roadbed and the deadweight load of the foundation, and excavate the slope of the old road, and the light-weight soil is poured into layers. The nonlinear structural analysis of the stress response of lightweight soil widening roadbed during construction and under different widening section sizes is carried out, and a force transfer mechanism similar to that of rigid foundation is put forward, which is similar to that of rigid foundation. Combined with the effect of hard shell and the characteristics of load distribution of lightweight soil, the development trend of displacement at different positions of widening roadbed is explored, in order to make clear the weak area of stress and the concentrated area of displacement development in widening roadbed of light soil. Finally, through the principle of strength reduction, Based on the analysis of the overall stability of the light soil widening roadbed, the effects of the material parameters of the light soil, the shear strength of the soft foundation and the hard shell layer on the overall plastic zone and lateral displacement development of the roadbed after widening are discussed. The forming characteristics of plastic zone and failure mechanism of high narrow and low width widening roadbed are compared and studied so as to guide the adjustment of design parameters of lightweight soil material. The important position of joint treatment of geotechnical materials and the targeted reinforcement of soft foundation are determined.
【學位授予單位】：河北工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U416.1

【共引文獻】

相關期刊論文 前3條

1 魯洪強;周明輝;鄒淑國;;土工格柵在道路拓寬工程中的應用研究[J];山東交通學院學報;2010年03期

2 邱勇;楊立新;;軟土地基舊路拓寬工程路基沉降變形規(guī)律分析[J];山西建筑;2010年30期

3 袁平;;淺談道路橋梁路基施工前準備[J];民營科技;2011年05期

相關碩士學位論文 前10條

1 李濤;西—潼高速公路拓寬工程路基差異沉降機理及地基處治技術研究[D];長安大學;2011年

2 陳靜;內蒙古地區(qū)公路加寬工程新舊路基差異沉降分析[D];內蒙古農(nóng)業(yè)大學;2011年

3 李俊峰;廣陜高速公路拓寬路基沉降控制技術研究[D];長安大學;2010年

4 郭國梁;寒區(qū)塑料板排水法處理軟土地基穩(wěn)定性研究[D];東北林業(yè)大學;2010年

5 鄒琳琳;三峽庫區(qū)夾灘場鎮(zhèn)庫岸邊坡穩(wěn)定性分析與庫岸再造預測[D];吉林大學;2012年

6 馬正;土石壩拓寬加固的安全穩(wěn)定性分析[D];山東大學;2012年

7 牛強;西寶高速公路改擴建新舊路基結合部處治技術[D];長安大學;2012年

8 李丙銀;高速公路高填方路基加寬不協(xié)調變形控制的關鍵技術研究[D];石家莊鐵道大學;2012年

9 劉高喜;高橋臺錐型護坡的土體穩(wěn)定性分析[D];河南工業(yè)大學;2013年

10 楊懷丹;路基小幫寬沉降性能的研究[D];哈爾濱工程大學;2013年

，

本文編號：1542858