水泥-固废基固化流态膨胀土溶洞注浆充填材料特性研究

Research on Characteristics of Grouting Filling Materials for Cement-Solid Waste-based Solidified Fluidized Expansive Soil Cave

摘要:

针对高速铁路岩溶地区溶洞注浆材料成本高、环保性不足的问题，以粗粉煤灰、矿粉协同水泥，制备水泥-固废基固化流态膨胀土注浆充填材料。通过正交试验探究材料流动扩展度、单轴抗压强度的变化规律，并结合XRD微观试验揭示其水化机理。结果表明，水泥、粗粉煤灰对材料两项核心指标影响显著，流动扩展度随水泥掺量增加、粗粉煤灰与矿粉掺量降低而减小，抗压强度则随水泥与矿粉掺量增加、粗粉煤灰掺量降低而增大，材料最大流动扩展度达237 mm，28 d最大抗压强度为15.02 MPa。其水化产物主要为C-S-（A）-H、AFt，优化胶凝材料掺量、延长养护龄期可促进水化反应、提升强度。通过优化材料工作力学性能，得到适配高铁岩溶溶洞注浆的充填材料，为岩溶工程治理提供了低成本、绿色的解决方案。

Abstract:

Aiming at the problems of high material costs and insufficient environmental friendliness in grouting materials for karst caves in high-speed railway karst areas, a cement-solid waste-based solidified fluidized expansive soil grouting filling material is developed by using coarse fly ash and mineral powder in conjunction with cement. Through orthogonal experiments, the variation patterns of material flow expansion and uniaxial compressive strength are explored, and combined with XRD microscopic tests, the hydration mechanism is revealed. The results indicate that cement and coarse fly ash significantly affect two core indicators of the material. The flow spread decreases as the cement content increases and the coarse fly ash and mineral powder content decrease. Meanwhile, the compressive strength increases as the cement and mineral powder content increase and the coarse fly ash content decreases. The maximum flow spread of the material reaches 237 mm, and the maximum compressive strength at 28 days is 15.02 MPa. The hydration products are mainly C-S-(A)-H and AFt. Optimizing the content of cementitious materials and extending the curing period can promote the hydration reaction and enhance the strength. By optimizing the mechanical properties of materials, a filling material suitable for grouting in karst caves of high-speed railways is obtained, providing a low-cost and green solution for the management of karst engineering.