勘察-地基-土木-土建-实习报告(CFG桩)

河南城建学院《勘查技术与工程》实习报告专业勘查技术与工程实习类别生产实习时间2011-2012（1）12-15周指导老师学号姓名目录一、实习目的和任务························································································1二、实习概述··································································································11.实习地点·····························································································12.工程概况·····························································································13.实习工作·····························································································2三、实习内容··································································································21.CFG桩复合地基设计对勘察的要求·······················································22.CFG桩复合地基承载力计算··································································23.CFG桩复合地基设计·············································································31)设计思想······················································································32)复合地基设计及设计参数确定······················································43)布桩·····························································································54.长螺旋钻管内泵压CFG桩施工工艺·······················································61)施工设备······················································································62)CFG桩施工····················································································63)CFG柱施工中常见的问题及质量控制············································7(1)堵管···················································································7(2)窜孔···················································································7(3)钻头阀门打不开·································································8(4)桩体上部存气·····································································8(5)先提钻后泵料·····································································85.施工检验及验收···················································································91）施工检测····················································································9(1)CFG桩的检测·····································································9(2)CFG桩复合地基的检测·······················································92）CFG桩复合地基施工验收····························································9四、实习心得·································································································10五、附录········································································································111.拟建建筑首层平面图··········································································122.CFG钻杆钻头图··················································································13河南城建学院1/13一、实习目的和任务生产实习是勘查技术与工程专业教学计划的重要组成部分，是学生在校期间理论联系实际，增长实践知识的主要手段和方法之一。通过实习，使学生在学校所学到的理论知识与生产实践相结合，综合运用所学到的知识解决生产实践中遇到的问题，并验证、巩固和深化所学的理论知识，培养学生分析问题和解决问题的能力，通过亲身参与施工组织管理工作和参加一定的专业劳动，对系统了解专业情况，加深对专业理论知识的全面理解起着重要作用，同时也对顺利实现有学校到社会的转化，为毕业生能尽快胜任工作，打下一个良好的基础。实习的具体任务是:1.通过实习，巩固已学过的理论知识，尤其是专业理论知识；2.在教室实习和理论学习的基础上，进一步增强钻探工程、基础工程、工程勘察、掘进工程施工的感性知识，全面熟悉施工过程、掌握钻探工程、基础工程施工、工程勘察、掘进工程施工的基本知识和基本技能。3.为今后从事钻探工程、基础工程、工程勘察、掘进工程、岩土工程等领域的工作，分析解决实际工作只中的技术问题、实验研究新工艺、新方法打下实践基础。二、实习概述1.实习地点河南省商丘市夏邑县南桥西北角，公园·蓝波湾四期工程2.工程概况夏邑公园·蓝波湾工程位于夏邑县新区南桥西北角，紧邻古运河城，环境优美。小区风格是西班牙建筑风格。96m2至139m2是其主力户型。占地面积71928m2，建筑面积110000m2，总投资15000万，绿化率40%，总户数为800。公园·蓝波湾四期工程拟建建筑物由门面房和商品房组成。设计地上10层，地下1层；为框架——剪力墙结构；地下车库为地下1层，剪力墙结构。基础底板筏板基础。±0.00=25.5m。楼基础底板标高-7.3m，槽底标高-7.48=18.02m，地下车库基础槽底标高-6.98=18.52m。楼座核心区基底平均压力标准值为560KPa，其余（边缘区）范围基底平均压力标准值为230KPa。根据商丘市勘察设计研究院有限公司提供的《夏邑公园·蓝波湾项目岩土工程勘察报告》,主楼楼座基底座落在新近沉积的第2大层（②层）。地基承载力标准值（fka）为170kPa不能满承载力要求，故需要进行地基处理。2/13采用CFG桩复合地基，以满足承载力并保证差异沉降控制在允许范围。CFG桩复合地基的要求如下：主体结构产生的地基净反力标准值详平面，地基处理后的长期最大沉降量Smax≤50mm，倾斜变形许值可为0.0015。车库及其他建筑单元采用天然地基。3.实习工作跟随CFG桩机做打桩准备和打桩工作。三、实习内容1.CFG桩复合地基设计对勘察的要求按照国家标准《岩土工程勘察规范》GB50021--2001进行岩土工程勘察，并提供勘察报告。（1）工程勘察内容①查明岩土埋藏条件及物理力学性质、持力层及下卧软弱土层埋藏深度、厚度、性质及变化。②查明水文地质条件、地下水位、地下水对混凝土的腐蚀性。③查明填土厚度、填土时间以及填土材料的组成成分。若基础底面在填土层，应给出填土层的承载力特征值。（2）勘探点间距勘探点的布置应控制持力层层面坡度、厚度及岩土性状，其间距为10～30m。层面高差或岩性变化较大时，间距取小值。（3）勘探深度应取勘探总数的1/3～1/2作为控制孔，深度为桩尖以下基础宽度的1～5倍。（4）室内试验完成土的物理力学性质常规实验。对基础底面以下的土层进行灵敏度试验。查明这些土层灵敏度的大小，为褥垫层施工提供依据。对中、高灵敏度土，褥垫层施工时尽量避免对桩间土的扰动，防止产生“橡皮土”。（5）勘察报告除按国家标准提供勘察报告外，尚需特别提供或增加以下内容：①提供各土层的桩侧阻力和桩端阻力，桩侧阻力和桩端阻力一般按相同施工工艺的混凝土桩提供。②若有填土，应说明填土材料的构成及填土时间，尤其需要对可能给施工造成困难的工业垃圾或块石等予以说明；当基础底面在填土层上时，需提供填土承载力特征值。③提供基底以下土层的灵敏度，作为褥垫层铺设施工时选择施工设备和施工工艺的依据。④提供场地土层压缩试验曲线，并以表格形式给出不同压力p所对应的孔隙比e，作为变形计算的依据。⑤对基底以下各主要土层必须提供其承载力特征值，作为复合地基的设计依据。2.CFG桩复合地基承载力计算复合地基是由桩间土和增强体（桩）共同承担荷载的。目前复合地基承载3/13力的计算公式比较多，但应用比较普遍的有两种，其一是将桩间土承载力和单桩承载力进行合理组合叠加；其二是将复合地基承载力用天然地基承载力扩大一个倍数来表示。必须指出，复合地基承载力不是天然地基承载力和单桩承载力的简单叠加，需要对如下的一些因素予以考虑：(1)施工时对桩间土是否产生扰动或挤密，桩间土承载力有无降低或提高。桩间土当竖直方向上荷载不大时，对土起阻碍变形的作用，使土的沉降减少；荷载较大时，起增大变形的作用。(3)复合地基中桩的Q-s线呈加工硬化型，比自由单桩的承载力要高。(4)桩和桩间土承载力的发挥都与变形有关，变形小时，桩和桩间土承载力的发挥都不充分。(5)复合地基桩间土承载力的发挥与褥垫层厚度有关。3.CFG桩复合地基设计1)设计思想当CFG桩桩体强度用得较高时，具有刚性桩的性状，有的设计人员常将其与桩基础相联系，因此讨论一下CFG,桩复合地基与桩基础的区别显然是十分必要的。桩基础是一种常用的基础类型，桩在桩基础中既可承受竖向荷载，也可承受水平荷载。众所周知，桩是一种细长杆件，它传递水平荷载的能力远远小于传递竖向荷载的能力，设计时采用桩基础承受竖向荷载是扬其长，承受水平荷