连云港软土地基工后沉降与处治方案选择研究

发布时间：2018-05-01 01:41

本文选题：连云港 + 软土地基　；参考：《东南大学》2015年硕士论文

【摘要】：工后沉降是衡量软土地基处治效果的指标之一,过大的工后沉降会严重影响道路的工程质量与行驶性能。软土地基处治方案多样,各方案的适用情况与处治效果各有不同。目前,软土地基处治方案的选择还停留在主要依靠经验的阶段,时有软土地基工后沉降过大而影响道路使用性能的现象发生。为了有效控制工后沉降,保证软土地基处治效果,应对软土地基工后沉降和处治方案选择进行研究。连云港地区软土分布广泛,软土地基工程性质差,软土地基处治工程量大。论文分析了连云港软土的基本特征与主要处治方法,结合连盐高速连云港段沉降观测数据对工后沉降进行了预测和分析,运用Plaxis有限元软件研究了工后沉降的影响因素,提出了基于软土地基工后沉降的处治方案选择模型。首先,论文分析了连云港软土的基本特征与主要处治方法。论文总结了连云港软土的成因及分布规律、基本物理力学性质、抗剪强度、固结变形和蠕变等基本工程特性；分析了预压、水泥搅拌桩和刚性桩等连云港主要软土地基处治方法的运用比率,并对不同方法的特点、适用性、处治效果和经济性进行了对比分析。其次,论文结合连盐高速连云港段沉降观测数据对工后沉降进行了预测和分析。论文对比了几种常用曲线模型预测深层处治路段沉降的精度与适用性,证明了双曲线模型的优越性,并采用分段双曲线模型预测曲线呈台阶状的浅层处治路段的沉降；通过对大量断面的工后沉降预测和分析,探讨了深层处治路段和浅层处治路段的工后沉降特点。再次,论文运用Plaxis有限元软件分析了软土地基工后沉降的影响因素。论文建立了深层处治典型断面模型,分析了桩长、桩距和桩身模量对复合地基工后沉降的影响；建立了浅层处治典型断面模型,分析了软土层厚度、设计堤高、硬壳层厚度、预压高度和预压时间对工后沉降的影响,运用正交设计分析了各因素的敏感性,回归了浅层处治路段工后沉降的计算公式。最后,论文建立了基于工后沉降的软土地基处治方案选择模型。论文分析了现有选择模型的不足,将工后沉降作为影响方案选择的主要因素,分析了方案选择影响因素的层次；分析了各指标的的权重和评价等级确定方法；并结合连盐高速、临海高等级公路两个典型断面验证了基于工后沉降的软土地基处治方案选择模型的适用性。
[Abstract]:Post-construction settlement is one of the indexes to measure the treatment effect of soft soil foundation. Excessive post-construction settlement will seriously affect the engineering quality and driving performance of the road. The soft soil foundation treatment plan is various, each plan's application situation and the treatment effect are different. At present, the choice of soft soil foundation treatment scheme is still mainly based on experience, sometimes there is a phenomenon that the settlement of soft foundation after construction is too large, which affects the performance of road use. In order to effectively control the settlement after construction and ensure the treatment effect of soft soil foundation, it is necessary to study the settlement and treatment scheme of soft soil foundation. The soft soil is widely distributed in Lianyungang area. This paper analyzes the basic characteristics and main treatment methods of soft soil in Lianyungang, forecasts and analyzes the settlement after construction combined with the settlement observation data of Lianyunhai high-speed Lianyungang section, and studies the influencing factors of post-construction settlement by using Plaxis finite element software. The selection model of treatment scheme based on the settlement of soft soil foundation is put forward. First, the paper analyzes the basic characteristics and main treatment methods of Lianyungang soft soil. This paper summarizes the basic engineering characteristics of Lianyungang soft soil, such as its origin and distribution, basic physical and mechanical properties, shear strength, consolidation deformation and creep, etc. The application ratio of main soft soil foundation treatment methods in Lianyungang such as cement mixing pile and rigid pile are compared and analyzed. The characteristics, applicability, treatment effect and economy of different methods are compared and analyzed. Secondly, combined with the observation data of Lianyan high-speed Lianyungang section, the post-construction settlement is predicted and analyzed. This paper compares the accuracy and applicability of several commonly used curve models to predict the settlement of deep treatment sections, proves the superiority of hyperbolic model, and uses the piecewise hyperbolic model to predict the settlement of shallow sections with step shape curves. Based on the prediction and analysis of post-construction settlement of a large number of sections, the characteristics of post-construction settlement of deep and shallow sections are discussed. Thirdly, Plaxis finite element software is used to analyze the factors influencing the settlement of soft soil foundation after construction. In this paper, the typical section model of deep treatment is established, the influence of pile length, pile spacing and pile modulus on the settlement of composite foundation is analyzed, the typical section model of shallow treatment is established, the thickness of soft soil layer is analyzed, the height of embankment and the thickness of hard shell layer are designed. The influence of preloading height and preloading time on post-construction settlement is analyzed by orthogonal design, and the calculation formula of post-construction settlement in shallow section is regressed. Finally, the selection model of soft soil foundation treatment scheme based on post-construction settlement is established. This paper analyzes the deficiency of the existing selection model, takes the post-construction settlement as the main factor affecting the scheme selection, analyzes the levels of the influencing factors of the scheme selection, analyzes the weight of each index and the determination method of the evaluation grade, and combines with the high speed of connecting salt. Two typical sections of high grade highway near the sea verify the applicability of the selection model of soft soil foundation treatment scheme based on post-construction settlement.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.1

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