【作者】 王新辉；

【导师】 缪林昌；

【作者基本信息】 东南大学 ， 岩土工程， 2004， 硕士

【摘要】 连云港地区的软土是海相淤泥和淤泥质土。在连云港软土地区修筑高速公路时,通常采用水泥土搅拌桩地基处理方法使路基强度和变形满足工程的要求。该类软土压缩沉降量大,排水固结缓慢,地基稳定性差,造成高速公路建设中及建成后工程问题频繁出现。为此,本文针对连云港海相软土经水泥土搅拌桩处理后形成的双层地基进行固结理论和变形特征的研究,并将研究成果进行推广应用。取得了以下几方面的研究成果:1)针对连云港海相软土进行一维固结和三轴剪切试验,深入分析连云港海相软土的物理力学特性。2)模拟水泥土搅拌桩施工,在室内制备不同配比、不同龄期的水泥土试样,并进行无侧限抗压试验和三轴剪切试验,揭示水泥土的受力特性及破坏特性。3)运用超越方程,以双层地基一维固结解析解为基础,推导出二级加荷条件下双层地基的固结解析解;同时,通过荷载传递法并借助Laplace变换对双层地基的固结问题进行了数值求解;此外,根据实际的地基结构,建立了桩间土和下卧层的固结模型并分别进行求解分析。4)分析探讨了双层地基中各参数对双层地基固结的影响程度,并运用荷载传递法的解答计算了连-徐高速公路A1-A4标水泥土搅拌桩处理段的六个断面,计算结果与实测数据有较好的一致性。更多还原

【Abstract】 Lianyungang marine soft clay is muck and mucky soil. When the expressway is built in the district, the soft clay foundation is often treated by cement-soil piles. This marine soft clay is of high compression、lower drainage consolidation and poor stability for its roadbed. During engineering construction, the phenomena, as larger settlement deformation, crack and slide, often take place on the embankment. This paper is concerned with the consolidation and project application of the double-layered foundation for Lianyungang marine soft clay treated by cement-soil piles. The main results of the study are obtained as follows:1) In order to analyze and study the physical and mechanical characteristics of Lianyungang marine soft clay deeply, large numbers of basic mechanical characteristics tests and tri-axial shear tests are completed.2) In order to investigate the loaded and failure characteristics of the cement-soil, the cement-soils for the different ratio and different cure time are studied in the laboratory, and their unconfined compression tests and tri-axial shear tests are performed.3) Based on the solution of one-dimension consolidation, the one-dimension consolidation of the double-layered foundation is solved for two-grade loading in virtue of transcendental equation; Simultaneously, the one-dimension consolidation of the double-layered foundation is solved by means of Laplace transform for two-grade loading, and Stehfest numerical transform is applied in Laplace’s inverse transformation; Furthermore, according to the practical foundation shapes, the consolidation models of the soil between piles and the substratum are built and solved respectively.4) The effect of each parameters on the consolidation of the double-layered foundation is discussed, and the solution of load transfer method for double-layered foundation is applied in A1-A4 section of Lian-Xu expressway. The results of calculating settlement of the double-layered consolidation theory are basic agreement with the measuring settlement results.更多还原