深埋隧洞围岩破坏力学机制及新型支护结构锚固机理研究

The construction safety incidents have been occurred in the burued deeply tunnel constructed. And the reaseon is that the surrounding rock mass failure mode predicted, damage failure mechanism and reinforcement mechanism are not studied thorough. Therefore, it is adopted which the theoretical study, numerical calculation and physical model tests to reasearch on the surrounding rock mass failure mechanism of instability in the high stress buried deeply tunnel, as well as new supporting structure reinforcement mechanism. The first, based on the matter element, extension set theory and the computing of the correlation function and through the related degree computed, the relationship is established between the surrounding rock homeostatic function and the failure mode, and it is proposed that the matter element extension prediction model for tunnel surrounding rock material instability and failure. The second, the normal load and overload test laboratory test are done to tunnel model. Focus on the monitoring and analyzing the stress / strain of surrounding rock failure process, tunnel internal damage and crack development, as well as the forces of the new support structure. Meanwhile, the constitutive model is determined by laboratory experiments, and the numerical calculation model is established. Base on the ADINA secondary development, according to the constitutive model and the instability criterion, it is analyzed that the tunnel surrounding rock mass failure mode, instability situation as well as the force state of the new type supporting structure. So the New Support Structure anchoring mechanism is studied deeply. The research will provide some theoretical support and help for deeply buried tunnel construction and design.

深埋隧洞施工安全事故时有发生，究其原因就是围岩变形预测、破坏机理，以及锚固机制等相关问题研究还不完善。因此，本项目拟采用理论研究、数值计算和物理模型试验相结合的方法，对高应力深埋隧道围岩破坏机理及其新型支护结构的锚固机制进行研究。首先，在物元理论、可拓集合论和关联函数运算的基础上，通过关联度计算，建立围岩自稳函数和判据与变形破坏模式之间的关联，以及隧道围岩失稳破坏的物元可拓预测模型。然后建立数值计算模型，确定计算方案。利用大型地质灾害相似试验台建立三维物理模型，进行模型试验。通过数值计算和物理模型试验，深入研究不同岩性深埋隧洞开挖过程中围岩的应力/应变参数分布和演化规律，提出深埋隧洞围岩变形破坏的力学机制。引入新型支护结构，通过数值和模型试验，深入研究新型锚固支护结构的锚固机理。因此，本项目顺利完成所得之研究成果，将为高应力深埋隧洞围岩变形破坏机理和失稳控制措施合理应用提供强大的理论支持。

深埋隧洞施工安全事故时有发生，究其原因就是围岩变形预测、破坏机理，以及锚固机制等相关问题研究还不完善。为研究开挖过程中深埋隧硐不同岩性下围岩破坏力学机制及新型让压支护结构锚固机理。以深埋某巷道顶板砂岩为研究对象，研究了深埋隧硐围岩的变形特性与破坏形式。通过正交配比试验，得出砂胶比与相似材料中石膏含量为相似材料密度的显著控制因素，胶结材料中石灰含量与砂胶比为相似材料粘聚力、抗压强度、抗拉强度、内摩擦角的显著控制因素，选取相似材料各力学参数显著影响因素通过Matlab编程获得了相似材料多元回归方程，优化了深埋隧硐围岩相似材料配比。在此基础上，首先进行了室内无支护条件下不同硐型层状岩性围岩三维相似模型试验，发现构造应力下硐周围岩位移及应力呈破浪变化的非传统变化规律，同时围岩发生分区破裂现象，相邻分层破碎区域的平均半径之比数值约为1.2~1.4。并采用有限元数值软件 MIDAS-GTS再现了分区破裂现象，定性分析了深部岩体在构造应力作用下的破裂力学机制，建立围岩破坏预测模型。其次，进行了室内让压支护下深埋隧硐层状围岩相似模型试验，发现四种支护形式中刚性衬砌+让压锚杆的新型组合支护形式最有效地抑制硐周围岩分区破裂现象，减弱了硐周围岩应力与位移的波浪变化规律。并采用有限元MIDAS-GTS软件进行模拟，得到了四种支护形式下硐周围岩破坏云图、应力/应变及支护结构内力试验结果，通过分析开挖过程中让压锚杆内力与衬砌内力变化规律，研究了刚性衬砌+让压锚杆的新型支护结构的锚固机制，建立了锚杆抑制围岩分区破裂的力学模型。本课题中，对深埋隧硐围岩破坏预测、深部岩体破坏机制及新型支护结构锚固机理进行深入研究，为深部岩体变形破坏预测提供了理论依据同时为今后深部工程施工提供了指导建议，实际意义较大。