隧道洞身开挖及初支施工方案

1南山隧道及连接道（茶园路）一期工程隧道标（K0+405-K3+440）工程项目BT融资建设南山隧道工程洞身开挖及初期支护施工方案编制：复核：审批:中铁十五局集团有限公司南山隧道一期工程项目经理部2011年08月20日2目录一、编制依据·····················································································1二、南山隧道工程概括········································································1三、隧道总体施工方案········································································1四、隧道洞身开挖施工方案··································································21、普通段洞身开挖········································································22、人行、车行横洞、人行、车行横洞主洞加强段、紧急停车带施工········3五、初期支护施工方案········································································41、超前小导管预注浆支护·······························································52、湿喷砼施工··············································································63、锚杆支护施工···········································································74、钢筋网施工··············································································85、钢架施工·················································································8六、隧道施工测量及监控量测·······························································91、施工测量·················································································92、监控量测·················································································9七、超前地质预报·············································································111、地质预报内容·········································································112、地质预报方法·········································································123、信息收集与整理······································································13八、洞身开挖爆破设计······································································131、开挖方法及循环进尺································································132、钻眼、爆破方式与材料选择·······················································133、爆破参数确定·········································································134、钻爆设计···············································································135、爆破效果监测·······································································176、爆破安全距离选择···································································177、装药、填塞和起爆网路设计·······················································178、爆破施工···············································································179、爆破设计参数·········································································1910、爆破效果监测及爆破设计优化··················································21九、安全质量保证措施······································································211南山隧道洞身开挖及初期支护施工方案一、编制依据1、“南山隧道及连接道（茶园路）一期工程隧道标段（K0+405-K3+440）工程项目BT融资建设”招标文件及施工图设计文件。2、工地现场的实际情况和我单位的履约能力。3、现行的公路工程施工规范、质量评定标准及相关工程施工的技术资料。4、工程所涉及的国家和重庆市地方有关政策和法规，特别是安全质量、职业健康、环境保护、水土保持方面的政策和法规。二、南山隧道工程概括隧道位于主线里程桩号K0+405～K3+238M处，分为左右两线，各长2833M（双向四车道），隧道出口道路约200米（双向四车道），为城市公路长隧道。南山隧道西洞口位于南岸区上新街，东洞口位于瓦房子社。南山隧道净空标准按两车道布置，采用曲墙三心圆断面形式，隧道净宽10.8m，净高6.8m，隧道内轮廓线净空面积分别为72.19m2（带仰拱）及60.47m2（不带仰拱）。南山隧道穿越南温泉背斜，无活动性断层，区域地质整体稳定性较好，围岩以灰岩、白云质灰岩、泥质灰岩、白云岩、砂岩为主，少量软质泥岩、炭质页岩、泥岩，岩体较完整，围岩稳定性较好，但局部岩溶发育、煤层段岩体完整性较差。围岩为Ⅴ～Ⅲ级，且以Ⅲ级为主，Ⅳ、Ⅴ级较少。南山隧道围岩分级见下表；表1南山隧道围岩分级表(按衬砌类型统计)围岩级别项目环框段ⅤⅣⅢ长度（m）比例(%)长度（m）比例(%)长度（m）比例(%)长度（m）比例(%)左洞（2824.86m）35.91.272117.47334.7811.852243.1879.41右洞（2838.8m）35.91.262117.43357.0812.582234.8278.73三、隧道总体施工方案调配专业作业队进行南山隧道的施工，配备多功能作业台架、挖掘机、装载机、衬砌模板台车、大型自卸汽车为主的大型无轨运输机械设备，配套组成钻爆、2装运、喷锚支护、衬砌等机械化施工作业线，实现隧道快速作业。隧道在穿越破碎带、岩溶富水段、煤层瓦斯段带等不良地层时，施工中把超前地质预报纳入施工工序，建立以地质工作内容为先导、以监控量测为依据的信息化施工管理体系，根据预报结果采取相应的施工方案和技术措施，确保施工安全和质量。隧道开挖方法采用新奥法，开挖爆破采用光面爆破。Ⅴ、ⅣA级围岩采用台阶法开挖，开挖循环进尺1m，上、下台阶步距大于20m；Ⅲ、ⅣB级围岩采用全断面开挖，开挖循环进尺3m。开挖过程中坚持“短进尺、弱爆破、强支护、快封闭、勤量测”的施工原则，并及时进行监控量测，根据地质情况的变化调整施工方法步骤，确保施工安全。四、隧道洞身开挖施工方案隧道开挖前根据设计文件要求完成超前支护措施，本隧道洞身段超前支护主要为Φ42超前注浆小导管，主要适用于Ⅴ、ⅣA级围岩和Ⅲ、Ⅳ级洞身围岩中的局部破碎带（Ⅴ级支护）。1、普通段洞身开挖Ⅴ、Ⅳ级围岩采用台阶法开挖，钻爆法光面爆破，上半部采用简易工作台架、YT28风钻钻孔；下半部各断面均采用多功能台架配合风钻钻孔。上、下台阶步距大于20m，台阶法开挖部序见图1。图1台阶法开挖施工部序图3Ⅲ级围岩采用全断面开挖。施工方法及技术要求：(1)采用光面爆破，周边眼间距应在50~70cm，最小抵抗线应为60~85cm。周边眼采用间隔装药，装药集中度应在0.2~0.35Kg/m。(2)开挖轮廓见附图所示，开挖钻眼深度应控制在3m~3.5m。施工中根据炮眼利用率，选用合适的掏槽形式。(3)爆破后及时检查光面爆破效果及超欠挖情况，必须严格控制欠挖。拱、墙脚以上内断面内严禁欠挖。(4)严格控制超欠挖，钻眼前画出开挖轮廓线，标出炮眼位置，保证测量精度，严格控制周边眼外插角和装药量。(5)做好爆破设计，根据围岩变化及时调整钻爆参数，实现光面爆破的最佳效果。(6)台阶法施工需立钢拱架时，下台阶左右错开开挖，防止上台阶拱架拱脚同时悬空。(7)以“管超前、严注浆、短进尺、弱爆破、强支护、勤量测”作为进洞施工和软弱破碎围岩的施工原则。2、人行、车行横洞、人行、车行横洞主洞加强段、紧急停车带施工(1)横洞施工①横洞施工总体安排人行和车行横洞开挖对主洞的受力有一定的影响。为了保证工程质量和施工安全，开挖到横洞与主洞交接断面时，暂不开挖横洞，而继续主洞的开挖。在横洞与主洞交接断面上加强监控量测，待围岩变形基本稳定，混凝土强度基本形成后，再对横洞进行开挖。开挖后及时进行监控量测，必要时调整支护参数。②横洞开挖人行横洞、车行横洞开挖尺寸较小，采用全断面法光面爆破一次成型。在与主洞交接处开挖前详细观察地质情况，必要时采用超前支护，分步开挖法施工。人行横洞采用人工出碴，车行横洞采用ZLC50C装载机出碴。4(2)紧急停车带施工开挖至紧急停车带时，施工断面高、跨度大，为保证施工安全，按V级围岩施工工艺采用台阶法施工，首先在5米内由标准断面过渡至扩大断面，然后按大断面完成应急停车带开挖和初期支护，最后再回头反向扩挖5米过渡段。应急停车带两堵头墙处采用径向爆破切割，保证接头墙处轮廓平整、线性顺畅美观。五、初期支护施工方案隧道采用复合式衬砌。初期支护以锚杆、钢筋网、湿喷砼、工字钢拱架等为主要手段，并采用超前小导管注浆预支护措施。南山隧道支护设计表见表2。表2南山隧道支护设计表支护类型应用范围初期支护二次衬砌湿喷砼锚杆钢架间距辅助措施ⅤⅤ级围岩穿越煤线地带C30砼20cm厚，加入水泥用量的8%的硅微分；Φ6.5钢筋网@25*25cmCD25中空锚杆L=4m，@80*80cm梅花型布置0.6m共设三环帷幕注浆拱墙、仰拱为110cm厚的C30防水钢筋砼，加入水泥用量5%的砼防腐气密剂ⅤⅤ级围岩段及破碎带C25砼20cm厚；Φ6.5钢筋网@25*25cmCD25中空锚杆L=3.5m，@80*80cm梅花型布置0.6m超前小导管，L