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第1页共29页五菱路（解放路－井冈山路）新建工程深基坑土方开挖专项方案编制：审核：审定：编制单位：华北建筑有限公司二0一五年十二月二日第2页共29页目录1.工程总体概述····················································31.1工程概述······················································31.2工程概况······················································31.3方案编制依据···················································32.桥位处地质状况及工程特点·········································42.1桥位处地质概况················································42.2工程特点·······················································53.基坑开挖方案的拟定···············································63.1基坑开挖方案的拟定············································63.2基坑开挖预备方案···············································64.施工部署··························································64.1基坑开挖放坡依据··············································64.2基坑开挖断面图················································74.3基坑开挖顺序··················································94.4施工方法及施工要点············································94.5机械设备配置·················································104.6技术准备·····················································114.7基坑放样·····················································114.8基坑开挖·····················································114.9基坑开挖弃土处理··············································125.基坑开挖组织施工·················································126.工程质量保证措施·················································126.1质量目标······················································126.2质量保证措施··················································136.3质量检验评定标准及检验方法····································137.安全生产保证措施·················································147.1安全生产目标··················································147.2安全生产保证体系··············································147.3安全管理措施··················································147.4安全操作措施··················································167.5安全事故应急预案··············································188.文明施工环境保护保证措施·········································208.1文明施工措施··················································208.2环境保护措施··················································209.附件-土坡稳定性计算书············································22第3页共29页五菱路规划小桥基坑开挖专项技术方案1.工程总体概述1.1工程概述工程名称：五菱路（解放路－井冈山路）新建工程工程地点：春江镇孟城村建设单位：常州市春江镇政府设计单位：江苏省科佳工程设计有限公司1.2工程概况（施工图）五菱路（解放路－井冈山路）新建工程规划河道小桥为1－13M简支板梁桥，上部结构为先张法预应力混凝土梁板，下部结构为重力式桥台桥梁，桥梁中心桩号为K1+375.770，全长21.08M，全宽18.6M，桥面为10CM厚C50整体化现浇混凝土、柔性防水层及10CM沥青混凝土铺装。重力式桥台基础设计底标高为-1.00m，基础顶标高为十0.00m，基础齿坎底标高为一1.50m。原地面标高为+7.40m，基础长度为１９.６０m，宽为７.８５m，开挖深度为8.40m。桥梁周围为平地无其他建筑物，经调查开挖区内无地下管线等设施，场地平整，有利于基坑开挖施工。第4页共29页1.3本方案编制依据⑴五菱路（解放路－井冈山路）新建工程施工图纸。⑵桥位处地质勘察报告。⑶公路桥涵技术规范（JTG/TF50-2011）。⑷我公司现时的施工管理模式及设备、材料配备情况。⑸根据建质[2009]87号文(6)城市桥梁工程施工及验收规范CJJ2-2008(７)省、市有关《建筑工程现场文明施工管理办法》2.桥位处地质状况及工程特点2.1桥位处地质概况①-1杂填土：松散不均，主要由砼地坪夹碎砖、石子等建筑垃圾组成，沿线局部分分布，主要分布于道路里程桩号K0+942～K1+200m路段内。本层仅以C1孔有所揭露，层底标高为7.41m。该层土性不均，双桥静力触探qc平均值3.038MPa，fs平均值45KPa，属高压缩性土。①-2素填土：软塑～可塑，主要由灰褐色～灰黄色的粉质黏土组成，富含植物根茎及虫孔，除明塘以外的沿线路基普遍分布。该层层厚0.60～1.00m，平均0.83m，层底标高5.86～6.83m。该层土性不均，双桥静力触探qc平均值0.742MPa，fs平均值28kPa，属高压缩性土。以上土层地质年代为第四世纪全新世（Q4）第5页共29页②黏土：可塑～硬塑，为正常沉积土层，沿线场地内普遍分布。层厚6.00～6.50m，平均6.33m；层底标高-0.54～0.81m，平均0.22m。双桥静力触探qc平均值为1.918MPa，fs平均值为96kPa。属中压缩性土。③粉质黏土夹粉土：可塑，夹中密状粉质薄层，为正常沉积土层，沿线场地内普遍分布。层厚3.40～4.70m，平均4.05m；层底标高-4.27～-2.59m，平均-3.43m。双桥静力触探qc平均值为2.988MPa，fs平均值为102kPa。属中偏高压缩性土。④粉质黏土：可塑，为正常沉积土层，沿线场地内普遍分布。本层仅C3号孔穿透，揭露层厚为3.00m，层底标高为-7.27m。双桥静力触探qc平均值为1.898MPa，fs平均值为55kPa。属中压缩性土。⑤粉质夹粉质黏土：稍密～中密，夹软塑状粉质黏土薄层，为正常沉积层，沿线场地内普遍分布。本层仅C3号孔穿透，揭露层厚为3.90m，层底标高为-11.17m。双桥静力触探qc平均值为2.392MPa，fs平均值为44kPa。属中性压缩性土。⑥粉土：中秘，为正常沉积层，沿线场地内普遍分布。该层未揭露，揭露层厚为1.60m，双桥静力触探qc平均值为4.726MPa，fs平均值为101kPa。属中偏低压缩性土。以上土层地质年代为第四世纪晚更新世（Q3）第6页共29页2.２工程特点本工程位于五菱路（解放路－井冈山路）新建工程K1+375.770处，桥梁周围无建筑物，无其他影响工程施工障碍，场地平整，有利于桥梁施工及基坑开挖。勘察地质报告提供开挖层地质主要为硬塑－可塑粘土，地质工况较好。道路设计右侧人行道有一纵向污水管线，污水管线在穿过规划小桥段要求埋设在规划河床以下，与桥台基础底标高同一高程即一１.５０m.（见施工图）。所以在桥台基坑开挖中，桥台基坑右侧加宽２m，与污水管基础一次开挖，同时施工，避免两次开挖，重复施工。３.基坑开挖方案的拟定：3.1基坑开挖方案的拟定：根据以上地质报告和工程特性，重力式桥台基坑拟定为分层、分级、放坡开挖方案。土方开挖土坡稳定性验算附后。3.2基坑开挖预备方案：如果基坑开挖后发现地质状况明显与勘察报告不符，出现流沙土质等不良土质，暂定施工，及时汇报总监、业主及设计院，组织相关专家现场察看，积极采取井点降水、基坑支护或变更桥台设计方案等相应措施。４.施工步署４.１基坑开挖放坡依据第7页共29页由《公路桥涵施工技术规范》4.1.2中表4.1.2表明挖地基不支护加固的坑壁的坡度为：坑壁土类坡顶无荷载坡顶有静荷载坡顶有动荷载砂类土1：11：1.251：1.5卵石、砾类土1：0.751：11：1.25粉质土、粘质土1：0.331：0.51：0.75极软岩1：0.251：0.331：0.67软质岩1：01：0.11：0.25硬质岩1：01：01：0适用于基坑深度5米以内，坑壁土类按现行《公路土工试验规程》（JTJ051）划分。建筑工程施工手册中对放坡系数的规定放坡高度、比例确定表：土壤类别放坡深度规定（m）高与宽之比人工挖土机械挖土坑内作业坑上作业一、二类土超过1.201：0.51：0.331：0.75三类土超过1.501：0.331：0.251：0.67四类土超过2.001：0.251：0.101：0.33本项目桥位土质以粘性土、粉质粘性土为主，由《公路桥涵施工技术规范》4.1.2表，放坡比为１：０.5。为确保安全施工，放坡比例上层采用１:1.00,下层采用1:0.67，在开挖深度的二分之一标高点设置一平台，平台宽度四周均为1.5米。开挖过程保持挖机作业面需要、挖机上下坡度以及工人上下基坑的通道。4.２、基坑开挖断面图基坑开挖平面图第8页共29页基坑开挖横断面图第9页共29页基坑开挖纵断面图4.３基坑开挖顺序由于两桥台基础之间只相距5.38米,所以两个桥台作为一个基坑来开挖施工。基坑开挖从西向东逐步延伸开挖，开挖土方也是全部向东侧路基及河塘翻运，保持基坑周边不堆积弃土。基坑准备分两次开挖，第一次开挖在满足西桥台现浇施工时暂停开挖，在基坑检验合格后立即进行西桥台基础施工及污水管西侧深井施工。待西桥台现浇结束及深污水井施工基本结束，再继续开挖东侧桥台及污水井基坑，目的是尽量缩短基坑作业时间。4.4施工方法及施工要点基坑开挖第10页共29页基坑深度开挖也是分步（层）挖法，为配合基坑分级开挖施工，第一次开挖至深度的H/2（4.20米），。挖掘机由地面（原地面相对标高定为0.00米）挖至-H/2米，直接装汽车运走或推土机推运；在Ｈ/2形成平面后再次放样,并放出四周平台线后，开挖下层的H/2基坑。由两台掘挖机配合作业，一台挖掘机将土挖甩至上边