【作者】 靳军伟；

【导师】 郭院成；

【作者基本信息】 郑州大学 ， 结构工程， 2010， 硕士

【摘要】 我国的高速公路、铁路建设近年来突飞猛进,建设投资不断地增加,规模不断地扩大,随着我国高速公路逐步向中西部地区的延伸,出现了越来越多的高填方路基。与一般的较低路基相比,高填方路基填筑高度大、填筑面积和土石方工程量大、自重大。要求路堤本身具有足够的整体强度和稳定性,并控制总沉降量和沉降速率,如果不能满足使用要求,将严重影响交通安全及运输速度。对于软土地区的高填方路基,在填筑过程中会产生较大的超孔隙水压力,由于软土的渗透系数较小,造成超孔隙水压力消散速度较慢,土体的有效应力增长缓慢,影响路基变形的稳定性。高填方路基变刚度处理技术中的无砂混凝土小桩后处理阶段,有排水固结以及胶结和竖向增强置换多重作用,适用于处理饱和软土、粉质粘土、粘性土、素填土、杂填土的公路路基。本文通过总结现有的高填方路基处理方法及其计算理论,就高填方路基变刚度处理技术展开研究：研究了高填方路基变刚度处理技术的工作机理,认为无砂混凝土小桩后处理阶段可以有效地消散路堤填筑过程中产生的超孔隙水压力。使用有限元程序进行了高填方路基变刚度处理机理的数值模拟,研究了在路基填土过程中路基底部的孔隙水压力变化规律,以及处理过程中的路堤沉降和变形。进行了高填方路基变刚度技术工作性能的数值模拟,对高填方路基变刚度处理不同工况进行了计算,重点分析了关键工况的路基沉降、位移规律,以及粉喷桩和无砂混凝土小桩的应力分布规律。对高填方路基变刚度处理技术的关键参数进行对比计算,分析了变刚度高填方路基处理适用的土体,对比了进行不同处理方式情况下的高填方路基沉降变形特点,重点分析了不同桩长、桩体模量、桩间距情况下的路基处理效果,就路堤位移、桩体应力、超孔隙水压力等方面进行了研究。在现有复合地基研究的基础上,探讨了高填方路基变刚度处理技术的设计,并讨论了其关键技术参数的计算方法。结合工程实测数据,分析了变刚度处理技术对高填方路基的处理效果,为变刚度处理机理的研究提供了一定的数据支持。根据目前的研究成果,对高填方路基变刚度处理技术的发展前景和尚需进一步研究的课题进行了阐述。更多还原

【Abstract】 With the fast development of China’s freeway and railway constructions in recent years, both construction investment and scale are unceasingly expanding. Along with highway constructions gradually outspreading, there are more and more high-fill embankments in the mid and west area of China. Compared with normal road embankment, high-fill road embankment owns large height, wide fill area, and large quantities of conditions. Then request embankment itself has enough strength and stability, and control of total settlement and sedimentation rate, if cannot meet the demands, will seriously affect traffic safety and transportation speed.For freeway high-fill embankment in soft soil area, excess pore pressure is created during the fill process, because of the small permeability coefficient, excess pore water pressure dissipate slowly, so as the additional effective soil stress. Then influence the stability of roadbed deformation. The variable stiffness processing technology for high-fill road embankment, which has post treat period using non-sand concrete micro-pile, can speed up drainage ratio and cementing and vertical displacement. The technology can be used in the road embankment of saturated soft soil, silt clay, clay, plain fill, miscellaneous fill.Based on summarizing the existing high-fill embankment processing method and calculation theory, variable stiffness treatment technology of Embankment treatment is studied:The mechanism of high-fill embankment variable stiffness technology is studied, and convinced that non-sand pile treatment can dissipate the excess pore pressure creating during the fill process. By using FEM to study the mechanism for high-fill Embankment post treatment, the variation of the excess pore pressure, embankment settlement and deformation with the processing of the fill are calculated and analyzed.The variable stiffness high-fill Embankment work performance is studied by numerical simulation, different processing conditions are calculated. The key conditions of the embankment settlement, displacement, and the stress distribution regularity of cement-jetted pile and non-sand concrete micro-pile are analyzed.The technology of variable stiffness processing parameters is analyzed, and the applicability, deformation under different treatment is studied. The embankment behavior is simulated by changing the pile length, pile body modulus, pile spacing. The research concentrates on embankment displacement, pile stress and excess pore pressure, etc.Based on the researches of composite foundation nowadays, probing into the variable stiffness high-fill road design and calculation method of processing technology, and the key parameters are discussed.Combined with site measurement data, this paper analyzes the treatment effect of variable stiffness high-fill Embankment post-treatment technology; the research provides data for the mechanism studies.According to the current research, some advises are discussed for the further research of variable stiffness post-processing high-fill Embankment technology.更多还原