全-强风化花岗岩富水地层注浆加固机理研究

In underground engineering, the disasters such as water or mud inrush, instability and collapse have been easily caused by the fully-strongly weathered granite in water-rich stratum. The grouting is an effective technique for disaster controlling and reinforcement of the above geological conditions. Owing to the large geological difference of fully-strongly weathered granite in water-rich stratum, there are in urgent need to improve or enrich the grouting reinforcement theory with large amounts of related researches and effective data. The theoretical analyses, laboratory experiments, numerical simulations, modeling tests and in-situ tests are adopted to perform this research, meanwhile, the emphasis of this research are the in-depth studies for grouting reinforcement theory of fully-strongly weathered granite in water-rich stratum. The effects of geological characteristics and grouting parameters et al. on the spatial distribution of slurry gels and morphological characteristics are studied, and the main affecting factors and threshold values for the grouting modes conversion can be determined. The influencing mechanism of grouting on the mechanical performance of hardened stone body are revealed based on the bonding characteristics, microstructures and composition variation during the grouting process. The destruction condition and critical criterion of the consolidation body will be investigated under different geological environments, the mechanical analysis models will be constructed, the discrete element programs for grouting and mechanical analysis will be realized, and the reinforcement effects of grouting will be quantitatively evaluated, which will eventually provide effective guidance for the grouting engineering. The above research results effectively improve and enrich the grouting reinforcement mechanism of fully-strongly weathered granite in water-rich stratum, and it is of great significance for grouting theory and disaster controlling practice in the similar strata.

地下工程中全-强风化花岗岩富水地层极易失稳破坏、诱发突水突泥等地质灾害，注浆作为一种有效技术手段广泛应用于该类地层的加固治理，由于全-强风化花岗岩富水地层地质特性差异大，急需大量资料对相应注浆加固理论进行完善。本项目拟采用室内实验、理论分析、模拟实验、数值模拟和现场实验相结合的方法，对全-强风化花岗岩富水地层注浆加固机理展开深入研究。通过研究地质条件、注浆参数等因素对浆液凝胶体空间分布及形态特征的作用规律，确定注浆加固模式转换的主控影响及其阀值；基于注浆前后固结体胶结特征及化学变化，从微观结构与组成变化角度揭示注浆对固结体宏观力学性能的作用机制。研究固结体在不同地质环境下破坏条件及临界判据，构建相应力学分析模型并实现离散元程序化，实现注浆加固效果的量化评价，并用于指导工程实践。上述研究成果补充完善了全-强风化花岗岩富水地层注浆加固理论，对类似地层的注浆治理具有重大理论与实践意义。

全风化花岗岩具有“风化作用强烈、含砂量高，胶结性差，遇水极易软化崩解”等鲜明特征，当隧道建设遇到全风化花岗岩时极易诱发突水突泥等地质灾害。注浆作为控制全风化花岗岩地层突水突泥的有效手段，受被注介质特殊的物理力学特性的影响，呈现出不同的扩散模式及加固机制，亟需系统深入的研究。.本项目针对工程中危险性较高的全风化花岗岩地层，采用室内试验对其物理力学特性行了系统研究，界定了全风化花岗岩地层的特征属性；探讨了全风化花岗岩地层的浆液扩散加固模式，黏土矿物含量影响浆液扩散加固模式，随着黏土矿物含量的不断增大，全风化花岗岩地层注浆扩散加固模式划分为渗透扩散注浆模式、强渗透-低劈裂扩散注浆模式、强劈裂-低渗透扩散注浆模式、劈裂扩散注浆模式；基于全风化花岗岩注浆模拟试验，研究浆液性质、注浆压力对其扩散模式及注浆加固体强度特征的影响机制，单双液浆在地层中均以劈裂扩散为主，但水泥浆液呈直线式和放射式两种，其主控因素为水灰比，而水泥-水玻璃浆液的扩散模式主要为放射式和网络式，扩散模式则受水灰比和注浆压力双因素影响。两种浆液均提高加固体抗压强度、抗崩解性，根据对加固效果的作用关系可将水灰比分为注浆压力作用区（水灰比0.8-1.13）和水泥-水玻璃浆液优势区（水灰比1.13-1.5），水泥浆液多适用于深部高压加固区，C-S浆液多适用于浅部低压加固区。最后依托广西均昌隧道突水突泥注浆治理工程开展了大量的现场试验，验证了该方法的实用性和高效性。