土方施工方案

台州解放南路改造(东侧)03-01地块工程土方开挖专项施工方案国强建设集团有限公司1目录一、编制依据········································································3二、工程概况········································································31、地质勘察概况····································································32、基坑围护概况····································································43、周边环境概况····································································5三、施工准备工作··································································5（一）、组织准备···································································5（二）、技术准备···································································6（三）、设备准备···································································6（四）、手续准备···································································6（五）、人员准备···································································6四、土方开挖技术要求及施工流程············································6（一）、基坑围护设计对挖土的顺序要求····································6（二）、基坑围护设计对挖土的技术要求····································71、施工顺序···································································72、开挖工作面································································7（三）、加强重点部位的施工····················································8（四）、中心区开挖顺序··························································9（五）、基坑排水···································································9台州解放南路改造(东侧)03-01地块工程土方开挖专项施工方案国强建设集团有限公司2五、土方施工技术及质量安全环保管理······································9（一）、土方开挖施工技术要点·················································91、土方开挖施工整体思路················································92、开挖顺序···································································103、开挖施工重点·····························································10（二）、挖土质量施工管理·······················································10（三）、安全技术和环保措施····················································13六、监测要求和应急措施·························································16（一）、现场监测内容及要求····················································16（二）、严重位移应采取的应急措施··········································18（三）、施工责任···································································19七、主要施工机械设备表·························································19八、施工危险源分析和措施·····················································20九、施工环境因素分析和措施··················································23十、土方开挖施工意示图·························································24台州解放南路改造(东侧)03-01地块工程土方开挖专项施工方案国强建设集团有限公司3土方开挖专项施工方案一、编制依据（一）台州解放南路改造(东侧)03-01地块基坑围护工程施工平面图，地下室施工平面图、基础施工平面图。（二）国家与地方有关建设工程质量，安全管理的规定、规则和规范。二、工程概况台州解放南路改造(东侧)03-01地块位于台州市椒江区解放南路，由二幢25层主楼（地下室一层）和三层裙楼组成。基坑长约120m，宽约73m，基础采用钻孔灌注桩。本工程地面平均标高相当于黄海高程5.30m，基础实际挖深为5.05m，局部电梯井深达9.50m，总挖土方量为46428m3。1、地质勘察概况岩土名称层序土层厚度M天然重度r固结快剪C（kpa）φk(°)填土○1粘土○2淤泥质粘土○3-11.9120.012.0淤泥○3-21.7810.08.0淤泥质粘土○3-31.658.05.0粘土○3-41.6913.011.0粘土夹角烁○41.7114.413.2含粘性土角烁○51.9225.015.0强风化凝灰岩○61.92台州解放南路改造(东侧)03-01地块工程土方开挖专项施工方案国强建设集团有限公司4中风化凝灰岩○7中风化凝灰岩○7c地下水潜水含水层接受大气降水和地表水补给，地下水动态随季节变化，水位变幅小，介质给水性、滲水性差，水量贫乏；深部烁石层赋水性、透水性较好，水量较少。勘察期间测得稳定地下水位在2.94~3.46m之间，根据03-02地块的水质分析资料，判定地下水对混凝土结构和混凝土结构中的钢筋无腐蚀性。2、基坑围护概况基坑主体采用φ700水泥搅拌，在A-A、B-B、F-F剖面采用φ600钻孔灌注桩结构。止水帷幕：A-A、B-B、F-F剖面采用一排Φ700的搅拌桩止水，搅拌桩之间搭界15cm，桩长以进入坑底9.9m控制，C-C、D-D、E-E剖面采用两排Φ700的搅拌桩止水，搅拌桩之间搭界15cm，桩长以进入坑底6.9m、5.4m、4.6m控制。土钉之间采用钢筋连接，土钉的布置及长度详见围护设计图。斜坡面喷射C20混泥土防止坡面裂缝渗水，垂直坡面喷射C20混泥土，喷射混泥土水灰比0.45，粗骨料粒径5~10mm，喷层初凝小于10分钟，终凝大于30分钟，喷射混泥土施工应满足ECS96-97规定。排水降水采用在基坑外侧和里面设置排水沟，用潜水泵及时降水抽出，防台州解放南路改造(东侧)03-01地块工程土方开挖专项施工方案国强建设集团有限公司5止坑底积水和坑底外侧水渗入坑内，同时设置水平排水管，间距2m，以排出坑壁后侧的积水。3、周边环境概况根据工程总平面图布置，并通过现场踏勘，西侧为解放南路。本施工场地狭窄，底板施工时应将施工堆放场地安在场地北侧。根据实际地开挖深度，基坑开挖面位于（2）或（3-1）层，均为粘土和淤泥质粘土，对围护结构的受力和变化控制相当不利。三、施工准备工作（一）根据建设单位提供的建筑红线、控制桩、水准点和施工图纸，进行测量放线工作。基坑开挖范围内所有轴线桩、水准点均引出机械施工活动区以外，并设置涂红白漆的钢筋支架加以保护。（二）根据轴线桩、施工图纸，测放基坑开挖线，并加以保护。（三）在现场搭设2个高6m的照明灯架，每个灯架安装3.5KW镝灯。工作面、坡道口安装碘钨灯活动灯架4个，供夜间施工照明用。（四）办理交通、城建、市政、市容、环卫等有关手续，准备弃土场，办理运土及渣土办手续。（五）施工人员组织：项目部组织了大型挖土机2台，自卸卡车20辆，清土人员40名，经三级安全教育后分成三个施工班组，日夜连续三班制施工。（六）临时道路：场地内在地下室挖土阶段设三条临时道路（详见挖土阶段施工平面布置图）；外运土方道路及缓冲平台均由挖掘机用碎石临时铺台州解放南路改造(东侧)03-01地块工程土方开挖专项施工方案国强建设集团有限公司6垫，并随土方外运弃置。四、土方开挖技术要求及施工流程（一）、基坑围护设计对挖土的顺序要求土方开挖应根据围护设计图纸编制详细、可行的土方开挖方案，挖土方案应由业主、围护人员协商确定。土方开挖应结合地下室结施图及围护桩平面布置图进行施工，确定放坡坑底边线及放线边线。1、土方开挖应沿四周首先开挖至相对标高2.80m，基坑边坡放坡比例按设计图纸施工，挖出一片须及时施工第一层土钉、铺设钢筋网片、浇捣压顶板混泥土和喷射坡面C20混泥土。2、待混泥土养护2天后方可机械开挖至坑底标高0.15m，人工清理土方至设计坑底标高，立即浇捣垫层（应控制在4小时之内），砌筑承台及地梁砖模。承台砖模砌至设计要求后，应及时用毛石混泥土或C10素混泥土浇捣填实承台外侧与围护之间的孔隙。（二）、基坑围护设计对挖土的技术要求1、施工顺序1)开挖工作面，修整边坡。2)完善排水系统（穿插在开挖和安放土钉的施工过程）。3)安放土钉。4)铺设、固定钢筋网。台州解放南路改造(东侧)03-01地块工程土方开挖专项施工方案国强建设集团有限公司75)喷射混泥土面层。2、开挖工作面1）施工条件应在水泥搅拌桩养护两周后方能进行工作面的土方开挖。2）分层开挖①土方开挖应与安放土钉相协调，应按设计规定的分层分段开挖深度（即土钉竖向距离）和安放土钉的施工顺序进行施工。②为确保工程质量，上层作业面的土钉与混泥土面层未完成，不得进行下一层深度的基坑开挖。3）分段施工对于大基坑，在分段安放土钉的前提下应分段开挖。分段长度一般为10~20m。5）修边坡采取任何开挖手段开挖，严禁边壁超挖或松动边壁土体。基坑边壁宜采用小型机具或铲锹切削修坡，保证边壁平整并符合设计边线尺寸。5）人工清理坑底为减少基坑底部的扰动，确保基坑底部质量，应在基坑底部留0.1~0.2m厚人工清理。6）易坍土体应采取防坍措施为防止暴露的边坡土体发生坍陷，对于高含水量的粘性土、淤泥土和无粘接力的砂土应立即进行支护，必要时可采取如下防坍措施：台州解放南路改造(东侧)03-01地块工程土方开挖专项施工方案国强建设集团有限公司8①在工作面上先铺设预制或现场焊接的钢筋网片，并喷射混泥土面层后再安放土钉。②减少分段开挖的长度。③先将作业深度上的边壁做成斜坡，