深部地下洞室开挖损伤区多参量识别及围岩变形预警研究

The deep underground caverns of large scale hydropower stations in the southwest of China are studied using the incorporated approach consisting of conventional testing, microseismic monitoring, theoretical analysis and numerical simulation. The formation mechanism and identification method of excavation damage zones, and the evolution characteristics and forecasting of surrounding rock mass deformation in deep underground caverns under high geo-stress are conducted. The constitutive relation of surrounding rock mass degradation considering the effects of rock mass damage is proposed. The deformation and failure characteristics of excavation damage zones are analyzed based on the multi-scale numerical models of deep underground caverns and a series of conventional testing and microseismic monitoring data. The evolution mechanism of microcracks (i.e., initiation, propagation and extension) in the processes of surrounding rock mass damage zones subject to excavation-induced unloading are investigated. The correlation among the scope of surrounding rock mass damage zones, cracks evolution and dynamic construction in the deep underground engineering are established. Furthermore, the formation mechanism, influence scope and 3D visualization of damage degree of the excavation damage zones in the deep underground caverns subject to construction disturbance can be realized. The multi-parameter identification method of excavation damage zones and forecasting system of surrounding rock mass deformation in deep underground engineering based on simulation and monitoring are thus put forward. The research results can provide some references for the parameters design of excavation and support in deep underground engineering, and ultimately serve to the large scale rock mass projects such as deep tunnels and underground cavern groups in the southwestern China, aiming to promote the improvement and rapid development of technologies on hydropower and traffic engineering in China.

以西南地区大型水电工程深部地下洞室为研究对象，利用常规测试、微震监测、理论分析和数值模拟等方法，开展高地应力条件下地下洞室开挖损伤区形成机理、识别方法和围岩变形演化规律及预测预警研究。提出考虑岩体损伤效应的围岩劣化本构关系，建立深部地下洞室多尺度数值模型，基于一系列常规测试和微震监测数据，揭示围岩开挖损伤区变形破坏特征，探讨开挖卸荷作用下围岩损伤区形成过程的微破裂萌生、发育和扩展的孕育演化机制，建立深部地下工程围岩损伤区范围、裂隙演化与施工动态之间的相互关系，实现工程扰动下深部岩体工程开挖损伤区形成机理、影响范围及损伤程度的三维可视化，提出基于模拟和监测的深部岩体工程开挖损伤区多参量识别方法及围岩变形预警系统。研究成果可作为深部地下工程开挖、支护参数设计依据，并最终服务于西南地区深部隧洞、地下洞室群等大型岩体工程，促进我国水电、交通工程技术的提高和快速发展。

本项目主要采用理论分析、现场监测、数值计算、工程实践相结合的研究方法，对深部地下洞室开挖损伤区进行多参量信息识别和围岩变形预警开展研究。主要研究内容包括以下几个方面：（1）调研和收集已有深部地下洞室工程微震监测、常规监测成果，依托典型水电工程地下厂房开挖损伤区现场，观察、记录和分析围岩损伤区产生的宏观变形失稳现象、规模和显现特征；基于模拟方法分析地下洞室围岩损伤区形成影响因素，研究分析地下厂房围岩损伤区触发机理。（2）建立了乌东德等地下厂房围岩损伤微震监测系统，实现了对地下厂房围岩损伤区孕育过程的实时监测分析，获得大量洞室围岩损伤破坏过程微震活动信息；研究了开挖卸荷过程地下洞室围岩损伤发生过程微震时空演化规律，揭示了地下洞室围岩损伤灾变孕育过程应力积累、应力阴影和应力迁移机制；揭示了地下厂房应力场扰动与微震演化规律的内在联系。（3）建立了典型水电工程地下厂房数值分析模型，研究了开挖过程地下厂房围岩损伤发生机理和影响因素；研究地下厂房围岩损伤孕育过程破坏机制，建立了地下洞室围岩损伤过程应力场、微震信息、常规监测信息相互关系，揭示了开挖过程深部岩体工程围岩损伤灾变机制；建立了围岩损伤与岩体力学参数之间的定量关系，通过提出的围岩劣化本构关系修正岩体力学参数，反演到地下洞室数值模型进行模拟分析，实现考虑岩体损伤效应的深部地下洞室围岩稳定性分析评价。（4）实现了地下洞室围岩损伤形成机理、范围以及损伤程度的三维可视化，揭示了围岩损伤孕育的前兆规律，建立了基于多参量监测信息和模拟的深部地下工程围岩变形预警方法。发表论文19篇，其中SCI论文11篇，EI论文6篇。获2019年度教育部科技进步一等奖及2017年第七届汪闻韶院士青年优秀论文奖。参编行业规范一部（水电工程岩体稳定性微震监测技术规范）。授权国家发明专利6项、实用新型专利2项。培养研究生9人。