海底隧道断层破碎带突水突泥与注浆加固机理及应用

Water and mud inrush mechanism of fractured fault zone and the theory of prevention and control is a crucial scientific problem needing to be solved during construction of subsea tunnels in our country. This project is planning to use a series of methods, including theoretical analysis, numerical simulation, laboratory test, model test and field test, to systematically study water and mud inrush mechanism of fractured fault zone, and the theory and methods of dynamic monitoring and pre-warning, and grouting reinforcement for prevention and control on disasters. Based on the geo-mechanics model of water and mud inrush disaster-inducing structural geology, research is to carry out on the instability and activation rule and disaster evolution mechanism of fractured fault zone under the influence of excavation disturbance and tiding load, and to propose pre-occurrence criterion of water and mud inrush disaster and the evaluation method of secure thickness value for inrush prevention; to study refined detection method on property information of fractured fault zone of subsea tunnel, and dynamic monitoring method on fault permeability; to study grouting penetration and reinforcement mechanism for fractured fault zone with seawater condition, reveal the attenuation rule of the strength of grouting reinforced body and supporting structure under the erosion effect of ions in the seawater, and propose a prediction model for long term stability of subsea tunnel; and finally to form grouting design and controlling method which is applicable for prevention and control on water and mud inrush disaster in fractured fault zone of subsea tunnel, with verification and refinement by field test. Research result is of great theoretical and practical value for controlling severe water and mud disaster of subsea tunnel and ensuring the safety of people's lives and property and preserving the ecological environment.

海底隧道断层破碎带突水突泥灾变机理与防控方法是我国交通基础设施建设中亟待解决的重大科学问题。本项目拟采用理论分析、数值模拟、室内试验、模型试验及现场试验相结合的方法，系统研究海底隧道断层破碎带突水突泥灾变机理、动态监测预警及注浆加固等灾害防控理论与方法。基于致灾构造地质力学模型，研究开挖扰动及潮汐荷载作用下断层破碎带失稳活化规律及灾变演化机理，建立突水突泥临灾判据及防突安全厚度确定方法；研究海底隧道断层破碎带属性信息获取与断层渗透性动态监测技术，提出灾害预警方法；研究海水环境下断层破碎带注浆扩散与加固机理，揭示海水离子侵蚀作用下注浆加固体与支护结构的强度劣化规律，建立隧道长期稳定性评价方法；最终形成适用于海底隧道断层破碎带突水突泥灾害防控的注浆设计与控制技术，并通过现场试验进行验证完善。研究成果对于控制海底隧道突水突泥重大灾害的发生、保障工程建设及运营安全具有重大的理论和实践价值。

本项目围绕海底隧道断层破碎带突水突泥灾变机理及注浆处治技术等关键科学与技术问题，开展了大量研究工作，按时完成了项目任务书规定的各项任务，在海底隧道断层破碎带突水突泥机理、四维广域实时感知监测理论与技术、断层破碎带注浆扩散与加固机理、注浆加固体长期稳定性等方面取得了重要研究进展，主要如下：.（1）划分了断层破碎带突水突泥灾害类型，建立了断层破碎带防突判据；开展了防突岩体破裂物理模拟试验，揭示了防突岩体最小安全厚度与水压、岩体强度的关系；开展了海底隧道断层破碎带突水突泥灾害三维模型试验，揭示断层失稳灾变过程中渗流场、应力场与位移场演化规律。.（2）提出了基于初始模型优化与不等式约束的跨孔雷达全波形反演方法和基于数据重组策略的电阻率联合反演方法，有效提高了对断层破碎带等不良地质体电阻率变化信息的反演精度与准确率，实现了对断层水运移过程的动态监测与快速成像。.（3）通过室内试验研究了海水环境下浆液时变特性，修正了浆液本构模型；建立了断层破碎带渗透/劈裂注浆扩散模型，揭示断层破碎带注浆扩散机理；通过室内试验，获得了海水环境对注浆加固体强度和渗透系数的影响规律。.（4）揭示了海水侵蚀与渗流双重作用下的注浆加固体劣化机理，建立注浆加固体性能劣化模型；通过数值试验及室内试验，研究了断层破碎带注浆加固体长期稳定性演化规律。.（5）提出了断层破碎带最优注浆加固圈厚度优选方法，研发了前进式分段、深部定域等注浆工艺，提出了注浆压力差异控制、注浆速率梯度控制等注浆过程控制技术。.以上研究成果已在国内外学术期刊发表论文20余篇,申请发明专利10余项。部分成果在青岛地铁1号线海底隧道工程中推广应用，针对断层破碎带内高风险失稳区域制定了超前探测与注浆治理方案，保障了隧道的顺利贯通。