【作者】 赵宏华；

【导师】 韩选江；

【作者基本信息】 南京工业大学 ， 岩土工程， 2003， 硕士

【摘要】 水泥搅拌桩加固地基是软土地基处理中最常用的一种方法。因其无振动、无噪音和无污染等优点，在旧城改造的密集建筑群中得到广泛的应用。但是，由于设计理论存在一些误区，特别是对其沉降变形的研究工作处于滞后的状态，设计人员往往担心拉大桩距后会加大基础沉降，故设计时常采用按小桩距(S＜2d)的常规设计方法。 搅拌桩复合地基按常规方法设计时一般取0.8m～1.2m的小桩距进行满堂布桩。而对于S＞2d的大桩距搅拌桩复合地基却使用很少。本课题针对大桩距搅拌桩复合地基的工程实例，开展荷载～沉降关系的研究，探讨其工作机理和设计方法。具体内容如下： (1) 分析探讨了搅拌桩复合地基桩长、置换率、桩身变形模量、桩距等因素对复合地基沉降的影响； (2) 探讨了大桩距搅拌桩复合地基在“有效桩长”内形成“加筋垫层”扩散应力的机理；提出了大桩距复合地基沉降按双层地基理论计算的基本方法； (3) 阐明了大桩距复合地基沉降计算的基本假定、计算公式和具体计算步骤，可方便于实际工程应用。 (4) 结合具体的工程实例，将大桩距复合地基的计算结果与实测的沉降变形结果进行了对比分析，并且根据小桩距复合地基工程实例的计算结果，提出了复合地基沉降计算方法的修正系数。 (5) 基于以上工作完善了大桩距搅拌桩复合地基的设计步骤，并探讨了按变形控制设计、优化设计方法的有关问题。同时，强调了完善施工组织设计和加强技术质量措施对确保大桩距复合地基设计质量的重要作用。更多还原

【Abstract】 Cement soil mixing pile reinforcing foundation is a method which is often used in soft-soil foundation treatment. Because it has many excellence, such as no vibration, no noise, no pollution, it is widely used in the old city reconstruction .but it has some mistakes on the design .Theoretic research still lags( And designer is often afraid that it will make the composite foundation settlement larger when pile spacing is larger. So traditional design method , littler pile spacing design method ,is often used.The pile spacing is 0.8m - 1.2m and piles is set in all the cite according traditional design method when mixing pile composite foundation is designed. But it is seldom used when pile spacing is more than two time pile diameter. This paper had load-deformation relation research, discusses its working mechanism and designing method according one larger pile spacing composite foundation, detailed content is as follows:(1) Discusses some factors affecting mixing pile composite foundation deformation such as pile length, replacement ratio, pile deformation modulus, pile spacing;(2) Discusses mechanism which large pile spacing composite foundation forms "reinforced cushion" to diffuse additional stress among the "effective pile length"; points out large pile spacing composite foundation’s settlement calculation method according double layer foundation theoretic;(3) In order to convenient for engineering applying, explains basic hypothesis - calculating formula and detailed computing steps of large pile spacing composite foundation settlement calculating,(4) Contacting detailed engineering example , compares between calculated and measured results of large pile spacing composite foundation; also computes out corrected coefficient of composite foundation settlement calculating method according calculated results of traditional composite foundation examples;(5) Perfects designing steps of large pile spacing composite foundation according above working; and discusses some questions of designing method according controlling deformation and of optimizing design method; also emphasizes it is important for insuring design quality of large pile spacing composite foundation to perfect constructing organize design and enhance technique-quality measures.更多还原