地下工程富水弱胶结岩体注浆加固机理与稳定性试验研究

Grouting has been indicated to be an effective technological method to prevent and control the geological disaster including collapse and inrush of clay and water, induced by water-rich weakly-cemented rock mass in underground engineering. However, the mechanism of grouting reinforcement is unclear and still to be further consolidated. It intends to use the grouting experiment associated with theoretical analysis, numerical simulation, microcosmic test, laboratory test to carry out the study. The rock structural variation under the grouting is analyzed and the grouting reinforcement patterns are divided based on the orthogonal test of grouting reinforcement. The interface characteristic of slurry and rock is studied, and the meso-mechanism of grouting cement strengthening and the change process of the macroscopic mechanic indexes for grouted body are revealed. The control effect of the interface on macroscopic mechanical properties is studied, and then the grouting reinforcement mechanism of the weakly-cemented rock mass is elucidated. The non-uniform deterioration process of grouted body under excavation, exterior load and groundwater pressure overloading is studied relying on the multiple drillings and sequenced 3D curtain grouting experiment. The destruction critical condition of excavating consolidated rock is proposed to revel the progressive destabilization destruction law of reinforcement rock. The research improves the grouting theory of underground engineering, and provide technical support for grouting management of geological disaster under similar condition.

地下工程富水弱胶结岩体极易诱发塌方、突水突泥等地质灾害，实践表明，注浆是防控此类灾害的有效技术手段，但相应的注浆加固理论尚不成熟，亟需进一步深入研究。本项目拟采用室内注浆试验方法，结合理论分析、数值模拟、微观测试分析、岩石力学测试等手段开展研究。基于注浆加固正交试验，分析注浆作用下岩体结构变化规律，归纳总结注浆加固模式；研究浆-岩界面特征，揭示注浆胶结强化细观机制与注浆固结体宏观力学性能变化过程；进一步研究注浆固结体破坏力学特征，揭示浆-岩界面对宏观力学性能的控制作用，阐明富水弱胶结岩体注浆加固机理。依托三维帷幕注浆模拟试验，研究开挖作用、地应力与地下水压力超载试验条件下注浆帷幕体非均匀劣化过程，提出加固体破坏临界条件，揭示工程扰动与地质环境影响下的帷幕体渐进失稳破坏规律。本项目研究成果补充和完善了地下工程注浆加固理论，为类似条件下的地质灾害注浆治理提供了技术支撑。

地下工程建设及运营期间，富水弱胶结岩体及裂隙岩体等不良地质体极易诱发塌方、突涌水、突泥等地质灾害，实践表明，注浆是防控此类灾害的有效技术手段，但相应的注浆加固/堵水理论尚不成熟，亟需进一步深入研究。本项目采用室内注浆试验方法，结合理论分析、数值模拟、微观测试分析、岩石力学测试等手段开展研究。首先，以典型的全风化花岗岩土为研究对象开展室内注浆加固试验，基于注浆参量选取及被注介质条件提出了全风化土的可注性判据，归纳总结了破碎岩土体注浆扩散加固模式；获取了注浆加固体强度及抗渗性能随注浆参量及被注介质条件的变化规律，建立了加固体单轴抗压强度及渗透系数与各指标（即注浆参量与被注介质条件）之间的定量关系。其次，利用三维注浆模型试验系统开展了黏土介质单孔/多孔注浆模型试验，获得岩体内部物理场时空演化规律，表明小注浆速率、多孔联合注浆方式显著提高黏土压缩固结程度，利于改善土体力学性能；通过破碎岩体帷幕注浆加固体稳定性试验，分析了注浆加固体在开挖和水压超载试验中的渐进失稳过程，提出了评价注浆效果的加固安全度理论公式。最后，深入分析了注浆材料流变特性、扩散路径及注浆方式等因素平板裂隙注浆过程的控制作用，推导了浆液在平板裂隙中扩散控制方程，获取注浆参量、浆液流变性及裂隙尺寸对速凝浆液扩散过程中的控制作用；进一步提出了可描述多工况裂隙注浆扩散过程的步进式算法，开展了典型动参量裂隙注浆过程的研究，分析了不同注浆方案下注浆压力、注浆速率及浆液扩散距离等关键指标的变化特征，在一定程度上揭示了动参量裂隙注浆扩散规律，深化了岩体裂隙注浆机理的认识。本项目研究成果为富水破碎岩体及裂隙岩体的注浆加固/堵水设计和工程实践提供了有意义的指导。