黄土地区地铁车站PBA工法导洞形式优化分析  

Optimization Analysis of Heading Form of PBA Construction Method for Metro Station in Loess Area

作　　者：王博[1,2] WANG Bo(China Railway First Survey and Design Institute Group Co.,Ltd.,Xi'an 710043,China;Shanxi Railway and Underground Traffic Engineering Key Laboratory(FSDI),Xi'an 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043 [2]陕西省铁道及地下交通工程重点实验室(中铁一院),西安710043

出　　处：《铁道标准设计》2020年第4期117-122,129,共7页Railway Standard Design

摘　　要：针对黄土地区地铁车站PBA工法导洞形式优化方案及其影响,依托西安地铁8号线新植物园站工程开展研究。借助三维数值模型进行原方案与优化方案的对比分析,重点探究导洞形式优化对地表沉降及车站结构内力的影响。最后,讨论并给出PBA工法导洞形式优化施工的加固措施。结果显示:不同施工顺序下导洞形式优化导致地表沉降值增长20.41%~26.44%;车站结构内力提升且分布特征改变,但内力变化对结构安全影响较小。最优施工顺序为导洞先上后下、先边后中,扣拱先边后中。通过采用下导洞大管棚注浆与锁脚锚杆等加固措施,可有效缓解导洞形式优化引起的地表沉降变化。导洞形式优化可作为黄土地区PBA工法施工遭遇地基承载力不足问题的可靠处理方式。According to the optimization plan and its influence on the PBA method for metro station in loess area, researches are carried out based on the New Botanical Station project of Xi’an Metro Line 8, three-dimensional numerical model is used to compare and analyze the original scheme and the optimization scheme. The focus is placed on the influence of the optimization of heading form on surface settlement and internal force of station structure. Finally, reinforcement measures for optimizing the construction of PBA method are discussed and given. The results show that the optimization of heading form will cause the surface settlement value to increase by 20.41%~26.44% under different construction sequences. Besides, the internal force of station structure becomes larger and the distribution characteristics are changed, but the change of internal force has less impact on the structural safety. The optimal construction order is ‘top first, bottom last’ and ‘side first, mid last’ for heading, while ‘side first, mid last’ for buckle arch. Through reinforcement measures such as grouting and locking anchors in the large heading, the surface settlement changes caused by the optimization of heading form can be effectively alleviated. The optimization of heading form can be a reliable treatment method in case of insufficient foundation bearing capacity during PBA method construction in loess area.

关 键 词：黄土地区 地铁车站 PBA工法 导洞形式 优化分析 数值模拟 加固措施 

分 类 号：U455.421[建筑科学—桥梁与隧道工程]