一种泥质软岩隧道纳米硅溶胶－铝酸盐水泥复合浆材设计及性能优化分析

针对泥质软岩隧道注浆加固需求以及常用单一浆材性能存在的弊端，将纳米硅溶胶和铝酸盐水泥作为主剂，按照硅溶胶∶水∶铝酸盐水泥为100 mL∶100 mL∶120 g的基本配比组成复合注浆材料进行研究。初期研究发现，简单将纳米硅溶胶与铝酸盐水泥复合会导致结石率低且结石体存在裂缝等问题。针对结石率问题，选取硅酸钠和硅酸盐水泥，研究各自掺量对结石率、3 d抗压强度和凝胶时间的影响规律，在满足结石率达到100%的前提下，以3 d抗压强度为主、凝胶时间为辅，综合得出硅酸钠为提高结石率的优选外加剂，推荐掺量为铝酸盐水泥的1%。然后，将硅酸钠掺量1%作为常规配比用于后续试验。针对开裂问题，选取硅灰、氧化镁、氧化钙和可再分散乳胶粉，研究各自掺量对裂缝、3 d抗压强度和凝胶时间的影响规律。在满足裂缝得到完全治理的前提下，以3 d抗压强度和凝胶时间为参考依据，得出氧化镁为防治开裂的优选外加剂，推荐掺量为铝酸盐水泥的0.6%。最后，基于界面过渡区理论，评估优化浆材对滇中引水香炉山隧洞泥岩的加固效果。结果表明，岩-浆界面过渡区宽度平均仅88.6 μm，显微硬度下降幅度较小，岩-浆结合处微结构较紧固。

Design and Performance Optimization of a NanoColloidal SilicaAluminateCement Composite Grouting Material for Argillaceous Soft Rock Tunnel

In view of the grouting reinforcement requirements of argillaceous soft rock tunnel and the performance disadvantages of common single grouting materials, the nanosilica sol and aluminate cement is considered as the main agent, and a type of composite grouting material with silica sol/water/aluminate cement (100 mL/100 mL/120 g) is prepared. The preliminary study demonstrates that a simple combination of nanocolloidal silica-aluminate cement will lead to a low stone rate and cracks in the stone bodies. As a result, two admixtures of sodium silicate and Portland cement are chosen to study the influence of their dosage on the stone rate, 3 day compressive strength, and gel time. On the premise that the stone rate reaches 100% and the 3 day compressive strength and gel time are considered the main and auxiliary factors, respectively, the sodium silicate exhibits a better performance; its dosage is 1% of aluminate cement. Further, 1% sodium silicate is used as the conventional ratio for the subsequent tests. To solve the cracking problem, four admixtures of silica fume, magnesium oxide, calcium oxide, and redispersible latex powder are chosen to study the influence of their dosage on cracking, 3 day compressive strength, and gel time. On the premise that cracks can be completely treated and the 3 day compressive strength and gel time are considered as reference bases, the magnesium oxide has the best performance in cracking prevention, and the recommended dosage is 0.6% of aluminate cement. Finally, based on the theory of interface transition zone, the reinforcement effect of grouting material on the mudstone of the Xianglushan tunnel in Central Yunnan is evaluated. The results indicate that the average width of the magmatic interface transition zone is only 88.6 μm, the microhardness slightly decreases, and the interface between rock and grout is firm.