填石高填方超宽土基的沉降变形特性及计算研究

发布时间：2018-05-22 17:03

本文选题：高填方 + 超宽土基　；参考：《长沙理工大学》2014年硕士论文

【摘要】：近年来伴着西部大开发战略的实施,我国西部地区经济发展的步伐加快,为满足日益激增的交通运输需求,山区超宽高速公路和机场跑道的修建越来越多。由于山区地形起伏大、高差大,高填方工程不可避免。山区地质构造条件复杂,且高填方工程具有土石方量大、大面积施工的特点,导致高填方土基施工难度加大,变形特性及稳定控制与一般工程不同。充分的认识和把握高填方土基的变形及稳定特性,对于保证高填方超宽土基工程的质量、安全、工期的合理安排等甚为重要。目前针对土基填筑体自身沉降的计算及超宽土基的沉降计算尚无成熟的方法,特别是还没有简单适用的工程算法。对超宽土基沉降变形特性的研究也是目前有待解决的问题。首先,论文在查阅文献资料的基础上,总结分析国内外高填方土基的研究现状,结介绍了高填方土基的施工特点,总结了高填方土基的沉降计算方法。其次,通过对河池机场现场填料进行室内筛分实验,确定现场填料的级配。对比分析了超径料常用的缩尺处理方法之后,决定采用梯形分布相似法对填料进行缩尺处理；之后通过做粗粒土的大型三轴剪切试验获得填料的抗剪强度指标C(粘结力和咬合力)、φ(内摩擦角)。然后,在已有研究的基础上,分析研究超宽土基变形不同于一般土基的原因；根据剪应力系数(剪应力与路堤荷载的比值)沿水平向的变化规律,获得了基于地基剪应力的超宽土基判定方法；建立了地基表面沉降计算方法,并将高填方土基填筑体的自身压缩变形与之叠加,得出高填方超宽土基顶面的沉降量。通过室内试验获得河池机场工况的基本参数并结合工况资料,利用有限元软件系统的分析宽度、高度、地基土模量、边坡坡度等因素对高填方超宽土基沉降变形的影响,得到超宽土基由“弯沉盆形”渐变到“马鞍形”的临界宽高比为3-5。最后基于现场实测资料对高填方土基的工后沉降进行了参数模型回归预测,发现指数(ExcDep2)模型能较准确地反映高填方土基工后沉降变形规律。
[Abstract]:In recent years, with the implementation of the western development strategy, the pace of economic development in western China has been accelerated. In order to meet the increasing demand for transportation, more and more ultra-wide highways and airport runways have been built in mountainous areas. Because the mountain terrain undulates greatly, the height difference is big, the high fill project is inevitable. The geological structural conditions in mountainous area are complex, and the high fill engineering is characterized by large amount of earthwork and large area construction, which makes it more difficult to construct high fill soil foundation, and the deformation characteristics and stability control are different from those of general engineering. It is very important to fully understand and grasp the deformation and stability characteristics of high fill soil foundation in order to ensure the quality, safety and reasonable arrangement of construction period. At present, there is no mature method to calculate the settlement of the soil filling body and the settlement of the ultra-wide soil foundation, especially there is no simple and applicable engineering algorithm. The study of settlement deformation characteristics of ultra-wide soil foundation is also a problem to be solved at present. Firstly, on the basis of literature review, this paper summarizes and analyzes the current research situation of high fill soil foundation at home and abroad, introduces the construction characteristics of high fill soil foundation, and summarizes the settlement calculation method of high fill earth foundation. Secondly, the gradation of the field fillers is determined by the indoor screening experiment of the field fillers in Hechi Airport. After comparing and analyzing the commonly used scaling treatment methods of super diameter material, it is decided to adopt trapezoidal distribution similarity method to scale the packing. After that, the shear strength index C (adhesive force and bite force), 蠁 (internal friction angle) of fillers were obtained by the large-scale triaxial shear test of coarse grained soil. Then, on the basis of existing research, the reason why the deformation of ultra-wide soil foundation is different from that of ordinary soil foundation is analyzed, according to the variation law of shear stress coefficient (the ratio of shear stress to embankment load) along the horizontal direction, Based on the shear stress of the foundation, the method of determining the ultra-wide soil foundation is obtained, and the calculation method of the ground surface settlement is established, and the self-compression deformation of the high fill soil foundation is superimposed with it, and the settlement of the top surface of the super-wide soil foundation of the high fill is obtained. The basic parameters of Hechi airport operating conditions were obtained through laboratory tests, and the influence of the finite element software system, such as width, height, modulus of foundation soil, slope gradient, on settlement and deformation of super-wide soil foundation of high fill, was obtained by using finite element software system. It is obtained that the critical aspect ratio of ultra wide soil foundation is 3-5 from "sinking-basin shape" to "saddle shape". Finally, based on the field measured data, the parameter model regression prediction of post-construction settlement of high fill soil foundation is carried out, and it is found that the exponential Exc Dep2) model can accurately reflect the law of post-construction settlement deformation of high fill soil foundation.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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