【作者】 陈方；

【导师】 叶冠林； 严佳梁；

【作者基本信息】 上海交通大学 ， 建筑与土木工程（专业学位）， 2021， 硕士

【摘要】 地下连续墙具有整体性好、刚度大和抗渗性好等优点,被广泛用于基坑工程围护结构中。复杂地质和苛刻环境条件下,地下连续墙槽壁稳定性是目前工程界研究的难点和重点。本文依托上海市武宁路快速改建工程为背景,研究了砂质粉土层中地下连续墙施工过程中的槽壁稳定性问题及相应的槽壁加固措施,验证了槽壁加固措施的应用效果。主要研究成果如下:(1)剖析了武宁路快速改建工程的工程背景和项目特点与难点,通过数值方法研究了槽壁加固对地下连续墙槽壁变形和稳定性的加强效果。该工程场地10米深度范围内存在厚度较大的砂质粉土层,极易发生浅部土的坍塌问题。数值计算结果显示槽壁最大变形出现在该层土中,采用槽壁加固措施后能有效减小槽壁沿深度方向的水平变形。此外,槽壁加固深度越深,槽壁水平变形越小,表明该工程中槽壁加固措施的必要性以及槽壁加固对控制槽壁变形的有效性。(2)通过方案比选探讨了三种常见槽壁加固方式的优缺点和适用地质条件,研究了槽壁加固措施的加固机理和其施工工艺方法。结合武宁路快速改建工程的工程地质条件、工程安全等级和工程造价等特点,确定了三轴水泥土搅拌桩加固方法,并在未采取搅拌桩加固的区域,采用喷射井点预降水加固。(3)根据工程实测结果进行了槽壁加固措施的应用效果验证,对加固槽段和未加固槽段进行了充盈系数分析、超声波成像报告分析和槽壁外观质量比较。研究结果表明:未采用槽壁加固措施的槽段,有多个槽段出现充盈系数较大的情况,存在槽壁坍塌的可能性,而且观察基坑开挖后的槽壁外观发现其表面存在凹凸不平、渗水和混凝土夹砂夹泥问题。而槽壁加固的槽段全部的充盈系数均在工程经验取值范围之内,且槽壁外观质量良好,超声波成像报告显示加固槽壁的垂直度、均匀性也基本满足要求,证明了所采取的槽壁加固措施的有效应。更多还原

【Abstract】 The diaphragm wall has the advantages of good integrity,high rigidity and good impermeability,but how to ensure the stability of the groove wall of the diaphragm wall under complex environmental conditions is the focus of current engineering research.Based on the rapid reconstruction project of Wuning Road in Shanghai,this paper studies the stability of the trench wall during the construction of the diaphragm wall and the corresponding trench wall reinforcement measures,and analyzes the application effects of the trench wall reinforcement measures.The main research results are as follows:(1)The engineering background,project characteristics and difficulties of the Wuning Road rapid reconstruction project are introduced,and the influence of the channel wall reinforcement on the channel wall deformation and stability of the underground continuous wall is studied by numerical methods.There is a thick sandy silt layer within a depth of 10 meters in the project site,which is prone to collapse of the shallow soil.Numerical calculation results show that the maximum deformation of the groove wall occurs in this layer of soil.The use of groove wall reinforcement measures can effectively reduce the horizontal deformation of the groove wall along the depth direction.In addition,the deeper the groove wall is reinforced,the smaller the horizontal deformation of the groove wall,which indicates the necessity of groove wall reinforcement measures in this project and the effectiveness of the groove wall reinforcement to control the groove wall deformation.(2)The advantages and disadvantages of three common trench wall reinforcement methods and applicable geological conditions were discussed through the comparison and selection of options,and the reinforcement mechanism and construction techniques of these measures were studied,combined with the engineering of the Wuning Road rapid reconstruction project.According to the characteristics of geological conditions,engineering safety level and engineering cost,the three-axis cement-soil mixing pile reinforcement method is determined,and in areas where mixing pile reinforcement is not adopted,jet well point pre-dewatering reinforcement is used.(3)According to the actual measurement results of the project,the application effect of the tank wall reinforcement measures was verified.The filling coefficient analysis,the ultrasonic imaging report analysis and the appearance quality comparison of the tank wall were carried out on the reinforced tank section and the unreinforced tank section.In the groove section of the groove wall reinforcement measures,there are many groove sections with large filling coefficients,and there is the possibility of the groove wall collapsing,and the appearance of the groove wall after the excavation of the foundation pit is found to be uneven,seepage and concrete Sand and mud problems.The filling coefficients of all the groove sections reinforced by the groove wall are within the range of engineering experience,and the appearance quality of the groove wall is good.The ultrasonic imaging report shows that the verticality and uniformity of the reinforced groove wall basically meet the requirements.The effectiveness of the reinforcement measures on the tank wall is proved.更多还原