氯盐渍土安全处置对黄河流域工程建设、局域经济发展具有重要的经济和区位意义，研究、探索其原位工程应用的战略意义也是显著的。本文针对黄河流域宁夏-陕西段的榆林定边县氯盐渍土，基于将游离态Cl-向结合态转化的固化/稳定化理论，利用铝酸钙（CAC）-钡渣（BS）水泥为固化剂对盐渍土进行固化处理，采用室内试验宏微观力学试验-微细观表征-机器学习算法优化的方法，探讨此固化剂与现有纯CAC以及普通硅酸盐水泥（OPC）固化剂之间的差异性，以期解决固化耐久性与碳排放量问题，实现氯盐渍土高效资源化利用。主要研究结论与认识包括： （1）充分认识CAC-BS水泥固化剂的物理力学性能与安全性，揭示CAC-BS的微观结构演化机理。使用危险废弃物BS作为辅助胶凝材料（SCM）加入至CAC中得到CAC-BS水泥，较CAC而言，CAC-BS全龄期下的净浆强度较高且无明显的倒缩现象，初终凝时间延缓，水化放热峰的持续时间合理优化，微观结构更加稳定，且Ba2+的浸出浓度始终保持国家安全限值内，通过微观结构观察，CAC-BS较CAC水化产物类型组成变化显著，其内部生成较为稳定的C2ASH8与AFm相水化产物，其性能得到明显提；试验结果表明，CAC-BS中的BS添加量可推荐为20%。 （2）揭示了CAC-BS固化氯盐渍土物理力学特性演化规律，探明了多种环境影响下CAC-BS固化氯盐渍土的耐久性变化。对比CAC与OPC固化剂，CAC-BS在加入氯盐渍土时固化体系的最优含水率最小，固化体在7d，14d与28d龄期养护强度为3.14MPa，4.06MPa与4.14MPa均优于同龄期OPC固化体，28d龄期后期强度优于CAC固化体；对于加入了12%固化剂的固化氯盐渍土，在经历冻融循环、盐水浸泡与干湿循环耐久性试验后，CAC-BS固化氯盐渍土的强度始终为最高，经历10次干湿循环后为3.54MPa，经历10次冻融循环后为4.00MPa与经历10d盐水浸泡后为3.30MPa；CAC-BS在各耐久性条件下展现出稳定的质量与体积变化，在干湿循环下表观变化为生成斑点状孔隙通道，冻融循环下为表面粗糙化，在盐水侵蚀下则无明显表观变化。 （3）剖析了CAC-BS固化氯盐渍土在不同耐久环境条件下多尺度力学变化与固化 效果的关联关系。CAC-BS固化土无侧限抗压强度与微观硬度、纳米压痕硬度三者之间具有较强的线性关联关系，与纳米压痕弹性模量无关；割线模量E50与无侧限抗压强度和显微硬度具有较好的线性关联关系，与纳米压痕弹性模量和压痕硬度无关；随着养护龄期的增加，CAC-BS固化氯盐渍土的显微硬度与纳米压痕硬度测试点位的平均值越高，但其各平行测点之间的差异性随之增大；经历盐水侵蚀后，CAC-BS固化氯盐渍土的平均显微硬度与纳米压痕硬度增大；经历干湿循环与冻融循环后，CAC-BS固化氯盐渍土的平均显微硬度与纳米压痕硬度减小。随着养护时间的增大，CAC-BS固化氯盐渍土的纳米压痕弹性模量变大，在经历不同耐久性作用后，CAC-BS固化氯盐渍土的弹性模量均降低。 （4）揭示了多种环境条件下CAC-BS固化氯盐渍土微观结构与其相变演化机理。CAC-BS固化氯盐渍土的机理为水泥原始水化产物CAH10、C2AH8、C2ASH8、AH3结合氯盐渍土中盐分Cl-与SO42-稳定后的Ms、Ks以及Fs共作为盐渍土的骨架结构为盐渍土固化提供强度，水化产物的增加使得固化土的密实度更优，骨架结构更加牢固，多尺度力学参数显著提升。经历盐水侵蚀作用时，CAC-BS固化土表面会吸收充足的SO42-生成Et，内部结合盐水中的Cl-生成一部分Fs改变固化土水化结构组成；经历干湿循环作用时，干循环阶段产生很大一部分过渡性中间产物C3AH6，但会迅速结合盐渍土中未结合的阴离子，此外固化土中裂隙干循环阶段使一部分颗粒剥离，而在湿循环阶段不但会带走这部分剥离的颗粒，还会充分溶解氯盐渍土中的盐分离子；经历冻融循环作用后，CAC-BS中水化产物CAH10与C2AH8的转化作用减弱，但依然会因其内部水分的结晶膨胀作用产生一定的孔洞与裂隙，这种作用会使水化产物中释放一部分盐分离子，而固化土内部密实度会降低，水化进程的延缓也会使水化产物密度下降。 （5）建立了固化氯盐渍土多参数强度预测分析模型，可评价CAC-BS固化氯盐渍土的强度耐久性与生命周期。采用GBDT、MLR与SVR三种机器学习算法对固化氯盐渍土的强度进行了多参数有效回归，MLR模型回归确定达到相关路基规范规定的7d龄期上限强度标准5.0MPa时，需要CAC-BS固化剂添量为13.59%，OPC固化剂添量为15.48%，基于此标准添加量，计算出固化1t氯盐渍土时，CAC-BS材料在原料输入费用为91.469RMB，而在其生命周期内总计CO2排放量为46.972kg，远低于OPC的129.952kg，环境效益明显。

The safe disposal of chlorine saline soil holds significant economic and locational importance for engineering construction and local economic development in the Yellow River Basin. Research and exploration of its in-situ engineering application also carry substantial strategic significance. This study, focused on chlorine saline soil in Dingbian County, Yulin, in the Ningxia-Shaanxi section of the Yellow River Basin, has been based on the solidification/stabilization theory, which converts free-state Cl- into bound-state Cl-. Calcium aluminate cement (CAC) and barium slag (BS) cement have been used as solidifying agents for saline soil treatment. Through indoor macro- and microscopic mechanical testing, microscopic characterization, and machine learning algorithm optimization, this study has explored the differences between this solidifying agent and existing pure CAC as well as ordinary Portland cement (OPC) solidifying agents, aiming to address the issues of solidification durability and carbon emissions. The goal has been to achieve efficient resource utilization of chlorine saline soil. The primary research findings and conclusions include: (1) The physical and mechanical properties and safety of the CAC-BS cement solidifying agent have been fully recognized, and the microstructural evolution mechanism of CAC-BS has been revealed. By incorporating hazardous waste BS as a supplementary cementitious material (SCM) into CAC, a CAC-BS cement has been obtained. Compared to CAC, CAC-BS has exhibited higher paste strength across all ages without significant shrinkage, with delayed initial and final setting times. The duration of the hydration heat release peak has been reasonably optimized, the microstructure has become more stable, and the leaching concentration of Ba2+ has remained within national safety limits. Through microscopic structural observation, the hydration product composition of CAC-BS has shown significant changes compared to CAC, with the formation of more stable C2ASH8 and AFm phase hydration products, resulting in enhanced performance. The experimental results have indicated that the recommended BS addition in CAC-BS is 20%. (2) The evolution patterns of the physical and mechanical properties of CAC-BS cured chlorine saline soil have been revealed, and the durability variations of CAC-BS cured chlorine saline soil under various environmental conditions have been investigated. Compared to CAC and OPC solidifying agents, CAC-BS has exhibited the lowest optimal moisture content when added to chlorine saline soil. The compressive strengths of the solidified body at 7, 14, and 28 days of curing have been 3.14 MPa, 4.06 MPa, and 4.14 MPa, respectively, all higher than those of OPC solidified bodies at the same ages, and the long-term strength at 28 days has been superior to that of CAC solidified bodies. For chlorine saline soil with 12% solidifying agent, after durability tests involving freeze-thaw cycles, brine immersion, and wet-dry cycles, the strength of the CAC-BS cured chlorine saline soil has consistently been the highest, with a strength of 3.54 MPa after 10 wet-dry cycles, 4.00 MPa after 10 freeze-thaw cycles, and 3.30 MPa after 10 days of brine immersion. CAC-BS has exhibited stable mass and volume changes under all durability conditions, with the apparent changes being the formation of spot-like pore channels under wet-dry cycles, surface roughening under freeze-thaw cycles, and no significant apparent changes under brine erosion. (3) The relationship between multi-scale mechanical changes and the solidification performance of CAC-BS cured chlorine saline soil under different durability conditions has been analyzed. A strong linear correlation has been identified between the unconfined compressive strength (UCS), microhardness, and nanoindentation hardness of CAC-BS cured soil, while no correlation has been found with the nanoindentation elastic modulus. The secant modulus (E50) has shown a good linear relationship with UCS and microhardness, but no correlation with nanoindentation elastic modulus and hardness. As the curing age increased, the average values of microhardness and nanoindentation hardness testing points in CAC-BS cured chlorine saline soil have increased, though the variation between parallel test points has also grown. After saltwater erosion, the average micro-hardness and nanoindentation hardness of CAC-BS cured soil have increased, whereas they have decreased following wet-dry and freeze-thaw cycles. With longer curing time, the nanoindentation elastic modulus of CAC-BS cured chlorine saline soil has increased, but after exposure to various durability conditions, the elastic modulus has decreased. (4) The microstructure and phase evolution mechanism of CAC-BS cured chlorine saline soil under various environmental conditions have been revealed. The mechanism of CAC-BS cured chlorine saline soil involves the original cement hydration products CAH10, C2AH8, C2ASH8, and AH3, which combine with the cured salts Cl- and SO42- in the saline soil to form Ms, Ks, and Fs. These compounds serve as the skeleton structure of the saline soil, providing strength for its solidification. The increase in hydration products has enhanced the density of the solidified soil, strengthened the skeleton structure, and significantly improved its multi-scale mechanical properties. During saltwater erosion, the surface of CAC-BS cured soil absorbs sufficient SO42- to form ettringite (Et), while some Fs are formed internally by combining with Cl- from the brine, altering the composition of the hydration structure. During wet-dry cycles, a large amount of transitional intermediate product C3AH6 is generated during the drying phase but quickly combines with unbound anions in the saline soil. Additionally, cracks formed in the solidified soil during the dry cycle cause some particles to peel off, and the wet phase carries away these particles and dissolves the remaining salt ions in the chlorine saline soil. After freeze-thaw cycles, the transformation of hydration products CAH10 and C2AH8 in CAC-BS slows down. However, the crystallization expansion of internal moisture still generates some pores and cracks, releasing part of the salt ions from the hydration products and reducing the density of the solidified soil. The delay in the hydration process also decreases the density of the hydration products. (5) A multi-parameter strength prediction and analysis model for cured chlorine saline soil has been established, which evaluates the strength durability and lifecycle of CAC-BS cured chlorine saline soil. Three machine learning algorithms—GBDT, MLR, and SVR—have been used for effective multi-parameter regression of the strength of cured chlorine saline soil. The MLR model regression has determined that, to meet the upper strength standard of 5.0 MPa at 7 days as specified by relevant subgrade regulations, the required addition of CAC-BS solidifying agent is 13.59%, while that of OPC solidifying agent is 15.48%. Based on this standard dosage, it has been calculated that the cost of raw material input for stabilizing 1 ton of chlorine saline soil with CAC-BS material is 91.469 RMB, with a total CO2 emission of 46.972 kg over its lifecycle, significantly lower than the 129.952 kg of CO2 emissions associated with OPC, demonstrating clear environmental benefits.