硅溶胶慢渗固结泥质软岩的基础研究

This project researches modification process of silica sol for mudstone mainly by multiscale precision measurements, and reveals slow seepage rules of silica sol in grouting period and solidification mechanism after grouting. Grouting ability, diffusion difficulty, wetting ability, affinity and other grouting characters of silica sol will be studied by contrastive analysis tests with cement materials, high polymer materials and water; slow seepage and solidification experiments of intact rock samples and broken rock samples will be carried out to illuminate dynamic slow infiltration rules of slurry in multiscale fractures and to reveal the “microcosmic-mesoscopic-macroscopic” multilevel sealing rules of silica sol for mudstone by analyzing the adsorption, capillary diffusion, slow laminar flow, strong laminar flow of water and gas after grouting; three-dimensional network skeleton structure of silica sol will be tested and its "glue-friction-coupling" interaction mechanism with rock mass structure after grouting will be analyzed to illuminate the physicochemical reaction between colloid and rock mass during the strength developing period of silica sol, and to reveal solidification mechanism of mudstone by slow seepage grouting with silica sol; strength-increasing coefficient and anti-softening coefficient of intact rock, strength-recovery coefficient and anti-softening coefficient of broken rock will be put forward to analyze the mechanical properties improvement of mudstone after grouting with silica sol quantitatively. The research results can supply theoretical foundation for silica sol grouting to seal and strengthen mudstone, and provide a new idea to solve the watery softening and long-term large deformation challenge of mudstone.

本项目以多尺度精细测试为主，研究硅溶胶对泥质软岩的改性过程，揭示硅溶胶注入期慢渗规律和注入后固结机理。通过与水泥材料、高分子材料、水的对比分析测试，研究硅溶胶可注性、扩散难易、润湿能力及亲和能力等注浆特征；开展完整岩样和破碎岩样的慢渗固结实验，阐明浆体在多尺度裂隙中的动态慢渗规律，揭示硅溶胶注浆对泥质软岩中水、气等吸附、毛细扩散、缓慢层流、强烈层流的“微观-细观-宏观”的分级封闭规律；测试硅溶胶慢渗后的三维网状骨架结构状态并分析其与岩体结构的“粘结-摩擦-耦合”力学作用机制，阐明硅溶胶强度发展期间胶体和岩体之间的物化反应，揭示硅溶胶慢渗固结泥质软岩的改性机理；提出完整岩样的强度提高系数和抗软化系数、破碎岩样的强度恢复系数和抗软化系数，量化分析硅溶胶注浆对泥质软岩的力学性能改善效果。研究成果可为硅溶胶慢渗注浆封闭加固泥质软岩提供理论依据，并为解决泥质软岩的淋水软化和长期大变形难题提供新思路。

本项目以多尺度精细测试为主，研究硅溶胶对两类典型煤系软岩的改性过程，揭示硅溶胶注入期慢渗规律和注入后固结机理。通过与水泥材料、高分子材料、水的对比分析测试，研究了硅溶胶可注性、扩散难易、润湿能力及亲和能力等注浆特征，结果表明与其他常用浆材对比，硅溶胶的可注性最好，可注性的恶化拐点时间早于其流动性恶化拐点时间，且吸渗潜能显著；采用多种精细化表征方法测试了松散煤体和泥质软岩典型多级裂隙分布特征，结果表明两类煤系软岩均属于低渗介质，孔径分布呈“两头多，中间少”规律，微裂隙发育；开展了松散煤体、完整泥岩和破碎泥岩的注浆慢渗固结实验，阐明了浆体在松散煤体及泥质软岩的多尺度裂隙中的动态慢渗规律，揭示了硅溶胶注浆对两类煤系软岩中水、气等吸附、毛细扩散、缓慢层流、强烈层流的“微观-细观-宏观”的分级封闭规律，结果表明硅溶胶在松散煤体注浆渗透力学机制主要存在“驱替流-达西流-渗滤流”三阶段基本特征，低压慢渗可减缓注浆过程中的滞留效应，硅溶胶注浆显著地弱化了泥岩基质系统的吸附性能，对基质介孔的孔隙填充率可以高达50%以上，而且随着催化剂用量增加，封闭能力越好；开展了硅溶胶凝胶体及硅溶胶胶煤体的500天的长期力学性能测试，阐明了硅溶胶强度发展期间胶体和煤岩体之间的物化反应，揭示了硅溶胶慢渗固结松散煤体和泥质软岩的改性加固机理，研究成果可为硅溶胶慢渗注浆封闭加固两类典型煤系软岩提供理论依据，并为解决泥质软岩的淋水软化和长期大变形难题提供新思路。