载变引起地铁盾构隧道围压改变对结构承载性能影响机理研究

With the rapid development of underground railway transport, the construction adjacent to subway tunnel will affect the use function and safety, and even cause serious harm to the tunnel. This will bring a serious threat to the existing subway operation. Due to the lack of exact theoretical solution about the tunnel confining pressure in researches, the project focus on the common adjacent engineering construction to subway tunnel, especially aim at the excavation construction and ground loadings. Taking into account the shear fault deformation of tunnel segments as well as the vertical and horizontal interaction of tunnel, the structure-soil theoretical model will be established to obtain theoretical solutions of tunnel confining pressure. In succession, fine three dimensional finite simulations will be carried out. Based on the work above, further study on the effect of structure bearing performance caused by loading and unloading will be mainly discussed. Moreover, the results of large laboratory test will be performed. Comparison between results of laboratory test and the theoretical and numerical calculation and improvement of theoretical model will be made. At last, based on the accurate value of confining pressure, the exact solution for the vertical and transverse stress and deformation of the tunnel structure under loading and unloading will also be concluded in this project, as well as the influence law of loading and unloading on the bearing capacity of subway shield tunnel structure. It is hoped that the present research can reduce the possible disaster and economic losses by adjacent construction, and also can be a theoretical guidance to ensure the safety of the subway tunnel structure and operation.

随着地铁交通的快速发展，临近工程建设会对地铁隧道的使用功能和安全产生影响。相关工程建设会引起临近土体的荷载变化（加载或卸载），导致地铁盾构隧道产生纵向移动和横向变形，给既有地铁的运营安全带来严重威胁。本项目将改进现有研究中缺乏隧道结构围压变化理论解答的不足，针对基坑施工和地面荷载等常见的临近工程活动，考虑管片剪切错台变形以及隧道纵横向相互作用，建立隧道结构-土体理论模型，求解隧道围压变化的理论解并进行精细化三维有限元模拟，在此基础上，重点探讨加卸载对隧道结构纵横向承载性能的影响；同时，进行大型室内模型试验，将试验结果与理论和数值模拟计算结果进行对比验证。基于准确的围压，研究得到加载、卸载作用下隧道结构纵横向受力与变形的精确解，揭示加卸载作用对运营地铁盾构隧道结构承载性能影响的规律，减少临近工程施工可能造成的灾害和经济损失，为地铁隧道安全运营提供理论支持。

随着地铁交通的快速发展，临近工程建设会对地铁盾构隧道的使用功能和安全产生不利影响，加载或卸载会引起临近土体的荷载变化，导致地铁盾构隧道产生纵向移动和横向变形，严重时将导致螺栓断裂，接头部位损坏，管片裂缝增加等病害，对地铁列车运营安全造成严重威胁。.课题采用模型试验、理论计算、三维数值分析和工程实测等方法，对载变引起地铁盾构隧道围压改变对结构承载性能影响机理进行研究。首次提出一个以剪切错台为主、刚体转动为辅的盾构隧道变形模式，结合最小势能原理，推导出地面堆载和基坑开挖引起的下方和旁侧盾构隧道的纵向变形量、环间错台量、环间转角和环间剪切力的计算公式，研究得到不同影响因素的影响规律。考虑隧道纵横向相互作用，建立土体与隧道结构相互作用模型，首次求解得到地面堆载和基坑开挖导致下方隧道和旁侧隧道的围压变化理论解。进行不同地面加载工况下的大型室内缩尺寸模型试验，研究得到地面堆载导致的盾构隧道围压改变、受力和位移变化的规律，验证了隧道围压理论解的可靠性。基于准确的围压，计算得到加载、卸载作用导致的盾构隧道结构横向受力与变形量，分析得到影响规律。采用自主研发的盾构加载系统，进行了地面加载和基坑开挖卸载的三环盾构管片足尺寸模型试验，研究得到盾构管片的受力与变形规律，揭示了加卸载作用对运营地铁盾构隧道结构承载性能影响的机理，最终提取相应的安全性控制指标及控制值。.研究成果发表论文32篇（其中SCI收录8篇、EI期刊收录11篇）；授权发明专利1项、申请发明专利24项；授权实用新型专利14项；登记软件著作权12项；获得省部级奖励6项（其中浙江省科学技术奖三等奖2项）、地厅级奖励7项。培养毕业硕士研究生8人。通过研究地铁盾构隧道围压的改变，进而分析隧道结构承载性能的变化并进行安全性评估，为减少临近工程施工可能造成的灾害和经济损失，确保地铁隧道结构和运营安全提供理论支持，具有重要的社会及经济效益。