基于全固废的固化剂研制及其固化混合土的强度特性与固化机理研究

水泥是利用旋喷、搅拌等设备进行地基加固最常用的固化剂；天然地基常由多层厚薄不均的多种土组成，通过设备的上下往复形成混合土。研制一种能够替代水泥的适用于混合土的全固废固化剂，定量评价其经济和环境效益具有现实意义。采用研制的固化剂固化混合土，经标准养护后其无侧限抗压强度不低于同条件的水泥固化混合土强度。利用无侧限抗压强度试验，对比研究全固废固化剂固化混合土和同步制备的水泥固化混合土的强度特性、强度增长规律及浸水养护、冻融循环、干湿循环等环境下的耐久性；探讨不含拟合参数的强度-全龄期关系；利用扫描电镜及能谱、X射线衍射、热重分析、红外光谱、压汞试验、化学成分分析，并结合理论分析和数值模拟，阐明固化混合土的微观结构并揭示固化机理及耐久性机理；基于固化机理建立固化模型，结合数值模拟确立可用于不同级配混合土的全固废固化剂筛选优化理论方法，具有一定的理论价值并为旋喷、搅拌加固多层土地基工程设计提供支撑。

Cement is the most commonly used curing agent for foundation reinforcement using rotary jet, mixing, etc., equipment. The natural foundation is composed of multiple layers of soil with uneven thickness, and the mixed soil is formed by reciprocating up and down of the equipment. It has a practical significance to develop an all-solid-waste stabilizer suitable for mixed soil that can replace cement, and quantitatively evaluate its economic and environmental benefits. The all-solid-waste stabilizer consists of industrial solid wastes such as calcium carbide residue, fly ash, slag, phosphogypsum, red mud, nickel slag, etc., is used to solidify mixed soil which is composed of clay contents, silt contents, and sand contents in a certain proportion. After standard curing, the unconfined compressive strength of the all-solid-waste stabilizer solidified mixed soil is not lower than the strength of the cemented mixed soil under the same conditions. Using the unconfined compressive strength test, comparative study the strength characteristics, strength growth law, the durability under water immersion curing, freeze-thaw cycles, dry-wet cycles curing conditions between the all-solid-waste stabilizer solidified mixed soil and the cemented mixed soil which is prepared simultaneously. The strength-full age formula without fitting parameters is forecast for the all-solid-waste stabilizer solidified mixed soil and the cemented mixed soil. Scanning electron microscopy and X-ray energy spectroscopy, X-ray diffraction, thermogravimetric analysis, Fourier infrared spectroscopy, MIP mercury pressure test, chemical composition analysis, combined with theoretical analysis and Numerical simulation are performed on the microstructure of all-solid-waste stabilizer solidified mixed soil to reveal the solidification mechanism and durability mechanism. Based on reinforcement mechanism, the reinforcement model is established, and numerical simulation is applied to establish a theoretical optimization method screening and optimization of all-solid-waste stabilizer for different grades of mixed soil, which has a certain theoretical value and provides support for the design of multi-layer ground improvement engineering by rotary jet and mixing equipment.