【作者】 马士伟；

【导师】 梅志荣；

【作者基本信息】 中国铁道科学研究院 ， 桥梁与隧道工程， 2011， 博士

【摘要】 岩溶隧道穿越各种复杂特殊的地质、地貌和构造单元,在隧道施工中会产生各种地质灾害,其中涌突水地质灾害是岩溶隧道工程中危害性最大的灾害。本文对岩溶隧道涌突水地质灾害的破坏机理与预警技术进行了研究,包括其形成原因、破坏机理、预警方法和标准及现场应用。主要研究结论如下:(1)通过隧道涌突水地质灾害的调研,总结灾害发生必须具备四个基本条件,一是特殊的地质构造基础;二是足够的填充物条件;三是丰富的地下水源影响,四是人为的开挖扰动激活。(2)国内外对隧道涌突水地质灾害自动化网络监测系统的研究较少,目前在长大隧道施工过程中还没有广泛接受的、方便适用的监测数据处理模型,特别是对岩溶隧道涌突水地质灾害的预警预报,更没有成熟的先例。开发岩溶涌突水地质灾害预警信息系统对隧道安全施工有重要意义。(3)利用薄板理论、剪切破坏理论对岩溶隧道涌突水地质灾害发生机理和过程特征进行了研究。薄板理论适用于隧道跨度较大、隔水岩板完整性好并且较薄的情况,剪切破坏理论适用于隧道跨度较小、隔水岩板较厚并且破碎的情况。利用有限元对隧道开挖接近有压溶洞时隔水岩板力学变化进行了三维模拟。结果表明,由于隧道开挖引起围岩应力场变化和溶洞内水压作用,隔水岩板发生松弛,易导致灾害发生。(4)在岩溶隧道涌突水地质灾害预测预报方法上首次提出了灾害发生前兆的现象预报法和S—t曲线变化趋势判断法,该方法的关键是对施工中地下水活动规律和围岩稳定性实时监测,包括水压、水量、水质变化、围岩位移、初期支护应力变化等。(5)岩溶隧道涌突水地质灾害基本评判要素包括地质构造特征、涌水量特征、围岩稳定特征、地表环境影响、灾害危害程度。根据上述评判要素,对隧道涌突水地质灾害进行了IV级划分,这对制定灾害应急预案、防范工程风险有重要意义。(6)给出了不良地质隧道地质构造综合量化评价要素和评价指标,包括断层(性质、规模、岩性)指标值及权重因子、岩溶(层段、水系统、结构面发育程度)指标值及权重因子、隧道穿越地下水循环区域指标值及权重因子及水源补给特征指标值及权重因子,经过综合量化评价,确定量化指标值T。根据T值,将灾害风险程度划分IV级,对每一级分别确定监测项目,制定隧道通过该地段时的预警预测方案。(7)对岩溶主要风险源水压、水量、水质、初期支护内力及围岩位移进行监控,给出了相应的预警标准。在此基础上,研究开发了隧道涌突水地质灾害预警系统,并在浏阳河隧道过河段、大支坪隧道、野山关隧道现场使用。结果表明,该系统能较好的适应隧道复杂环境,稳定性好,其推广应用对岩溶隧道安全施工具有一定的指导意义。更多还原

【Abstract】 All kinds of geological hazards, particularly inrush water geology hazard which is the greatest hazards of all geological hazards, will occur when Karst tunnels go through complex special geology, geomorphology and tectonic units. Mechanism of inrush water geological hazards and warning technology of karst tunnel have been studied in this thesis, including causing, mechanism, theoretical analysis, forecasting method, warning method and standard and in-situ application. Conclusions are as follows.1. The formation and occurrence of water geology hazard must have four basic conditions which is separately that special geology structure, enough filling substances, abundant underground water and artificial excavation disturbance activation by analyzing mechanism and characteristics of inrush water of domestic and oversea karst tunnel.2. Automated network monitoring system of inrush water geology hazard of tunnel was seldom studied at home and abroad. The accepted widely applicable processing model of monitoring data has always been not presented at present, particularly warning and forecasting of inrush water geology hazard of karst tunnel which has no mature precedents. Therefore, it is of great importance to safety construction of tunnel to develop warning system.3. Thin plate theory and shear failure theory are used to study mechanism and characteristics of inrush water. The plate theory is suitable for large span tunnel with thin and well integrity water-resisting rock plate. On the opposite, the shear failure theory is suitable for small span tunnel with thick and broken water-resisting rock plate. Finite element method is used to simulate the changes of water-resisting rock plate mechanism while tunnel excavation closes to pressurized caverns in the 3D state. The results indicate that water-resisting rock plate begins to become relaxed and cause hazards easily.4. Disaster precursory phenomena prediction method and S-t curve tendency changes judge method is firstly presented on the basis of the prediction method of inrush water geology hazard of karst tunnel. The key of the method is to real-time monitor to activity patterns of underwater and stability of rock mass, including water pressure, water quality, around rock displacement, steel arch stress, etc.5. The basic evaluation factor of inrush water geology hazard of karst tunnel include tectonic features, water inflow features, rock stability characteristics, ground surface environmental features and harmful levels of disaster. It is of great importance to make disaster emergency plan that inrush water geology hazard is divided into four grades according to the above evaluation factor.6. The comprehensive qualification evaluation factors and the evaluation indexes of poor geology structures of karst tunnel was studied, included faults index and weight factors, karst index and weight factors, recalculating region index and weight factors that underground water goes through and water resource recharge characteristics index and weight factors. The qualification indexes T was determined by comprehensive qualification evaluation. Then harmful levels of disaster were divided into four grades according to value of T. The monitoring items are determined for each grade and the disaster emergency plan is made when tunnel excavation goes by the ground.7. The main risk resources of karst tunnel were monitored which was separately that water pressure, water flow, water quality, the internal force of preliminary support and the displacement of rock mass. And the relative standard values were made. The warning system of inrush water geological hazard of karst tunnel has developed on the base. The results of in-situ experiment in Liuyanghe tunnel of Wuhan-Guangzhou railway and Dazhiping Tunnel of Yichang-Wanzhou railway indicate that the warning system is quite stable and is able to adapt to complex environment, popularization and application of which has some guiding significance to construction safety of karst tunnel. It is instructive greatly to the application of the warning.更多还原