人工挖孔墩基础方案设计

目 录 一、工程概况 ························································································· 2 二、施工准备 ························································································· 3 2.1 材料及主要机具： ········································································ 3 2.2作业条件： ·················································································· 4 三、操作工艺 ························································································· 4 四、质量标准 ························································································· 9 4.1 保证项目： ················································································· 9 4.2 基本项目： ················································································· 9 4.3 允许偏差项目 ············································································· 10 五、成品保护 ························································································ 10 六、应注意的质量问题 ············································································ 11 九、主要安全技术措施 ············································································ 18 十、质量记录 ························································································ 20 十一、墩孔塌孔应急预案 ········································································· 20 11.1 目的························································································ 20 11.2 适用围 ···················································································· 20 11.3 相关文件 ················································································· 20 11.4 工程概况、危险目标的确定及潜在危险性的评估 ······························ 21 11.5 应急救援指挥领导小组机构、职责 ················································ 21 11.6 救援专业队伍的分工 ·································································· 22 11.7 对外的交流 ·············································································· 22 11.8 应急设备 ················································································· 23 11.9 伤害人员的抢救措施 ·································································· 23 11.10 有关规定 ················································································ 24

第一章 工程概况 1.1工程概况 本工程为马山工业园旧城改造一期项目A地块，本工程位于市江夏区谭鑫培路与马山路交汇处。本子项位于A地块，A地块包含A1#、A2两栋3层的商业裙房，A3#为29层的住宅，A4#为31层的住宅。各主楼尺寸如下： 1、地下室平面尺寸为189.7m*139.9m，地下室层数为两层，负二层结构层高3.85m，负一层结构层高5.7m。 2、A1#平面尺寸为80.25m*107.5m，一层层高5.7m，二层层高5.5m，三层层高11.05m，建筑总高度22.3m。 3、A2#平面尺寸为100.55m*107.5m，一层层高5.7m，二层层高5.5m，三层层高5.15m，建筑总高度16.4m。 4、A3#平面尺寸为58.22m*14.60m，裙房部分层高同A1#，标准层层高为2.95m，建筑总高度99.8m，属A类高度高层建筑。 5、A4#平面尺寸为58.22m*14.60m，裙房部分层高同A2#，标准层层高为2.95m，建筑总高度99.85m，属A类高度高层建筑。 人工挖孔墩位于A4#楼B2~B5/CA~AA区域。根据本工程基础勘察报告并结合现场实际试挖情况，基础持力层（强风化粉砂泥质岩）深度在2.5~5m左右，根据设计要求采用墩径φ1000圆形（扩底墩）人工挖孔墩加钢筋混凝土支护体系。进入持力层≥500mm，墩身采用C35级混凝土。基础等级：甲级 1.2地质概况 1.2.1根据地质工程勘察院提供的马山工业园旧城改造一期（A地块）项目岩土工程勘察报告，本工程场地地层按其成因、结构特征及强度自上而下共分为6层，上层滞水水位0.5m~2.6m（18.23~21.69m）各岩土层的地质时代及成因类型、顶板埋深、顶板标高、厚度、空间分布、岩土特征、工程性质详见下表： 地层编号 地层 名称 地 层 成 因 顶板埋 深 地 层 厚 度 层顶标 高 颜色 状态 压缩性 包含无及特征 分布情况

① 杂填土 Qml 0.00 0.50 ~ 6.60 19.21 ~ 23.81 杂色 松散 高 主要由粘性土组成，土层结构松散、性质不均匀，为新近回填土。 局部缺失

②-1 粉质粘土 Q4al 0.50 ~ 6.60 0.70 ~ 5.40 14.37 ~ 20.11 黄褐 灰褐 可塑 中 土质较均，含少量黑色铁锰质氧化物，干强度中等。 局 部 缺 失 ②-2 淤泥质粘土 Q4al 1.20 ~ 8.50 1.60 ~ 4.30 14.04 ~ 19.68 灰褐色 软塑 高 土质较均，含少量黑色腐殖质壳，手搓可成条。 局 部 分 布 ②-3 含角砾粉质粘土 Q3el+dl 0.00 ~ 10.50 0.70 ~ 6.00 11.74 ~ 20.52 黄褐色 硬塑 中 土质不均，局部偏可塑，含20%~35%泥岩或石英砂岩角砾，局部富集。 局 部 分 布 ③-1 强风化粉砂质泥岩 S2f 0.00 ~ 13.50 最大揭露厚度 50.5m 7.78 ~ 24.01 青灰色 强风化 低 粉砂-泥状结构，中厚层状构造，泥质胶结。岩体基本质量等级为V级。 全 场 分 布 ③-2 中风化粉砂质泥岩 S2f 2.50 ~ 45.50 未揭穿 -22.8 ~ 22.58 青灰色 中风化 不可压缩 粉砂-泥状结构，中厚层状构造，泥质胶结。岩体基本质量等级为Ⅳ级。 全 场 分 布

场地土类型和场地类别场地土层主要为杂填土、粉质粘土、淤泥粘

土、含角砾粘土。根据勘察经验场地土质fak大于150kPa。 第二章 施工准备 2.1材料及主要机具 2.1.1水泥：宜采用325号矿渣硅酸盐水泥。 2.1.2砂：中砂或粗砂，含泥量不大于5%。 石子：粒径为0.5～3.2cm的卵石或碎石。 墩身混凝土采用商品混凝土。 水：用自来水 2.1.6钢筋：钢筋的级别、直径必须符合设计要求，有出厂证明书及复试报告。 2.1.7一般应备有绞架、手推车或翻斗车、镐、锹、手铲、钎、线坠、定滑轮组、导向滑轮组、吊桶、振捣棒、插钎、粗麻绳、钢丝绳、安全活动盖板、防水照明灯（低压36V、100W），电焊机、扬程水泵、安全帽、安全带等。 2.1.8模板：组合式木模，弧形工具式木模二块拼装。卡具、挂钩和零配件。木板、木方等。 2.2作业条件： 2.2.1开挖前场地应完成三通一平。地上、地下的电缆、管线、旧建筑物、设备基础等障碍物均已排除处理完毕。各项临时设施，如照明、动力、通风、安全设施准备就绪。 2.2.2熟悉施工图纸及场地的地下土质、水文地质资料，做到心中有数。 2.2.3按配套道路，挡墙施工总平面图，设置墩位轴线、定位点；墩孔四周撒灰线。测定高程水准点。放线工序完成后，办理预检手续。 2.2.4按设计要求分段制作好钢筋笼。