电渗-酶促碳酸盐协同固化硫酸盐渍土试验研究

Experimental study on electro-osmosis and enzyme-promoted carbonate co-solidification of sulfate saline soil

  • 摘要: 针对于硫酸盐渍土因盐胀破坏和结构强度不足引发的工程病害,提出一种结合电渗析技术与酶诱导碳酸盐沉淀(EICP)的综合方法,改良硫酸盐渍土的工程性质。通过设计转换电极注浆(EU)、不转换电极注浆(EM)和直接注浆(EN)三组不同注浆方式的对比试验,系统探究电场作用下胶结液迁移-盐分排出-强度形成的协同机制。试验中,施加的电势差驱动土中盐离子随电渗水流排出;同时,EICP水解产生的Ca2+在阴极区与CO32−结合生成碳酸钙胶结物,共同实现土体强度提升。结果表明:(1)胶结液的注入使电流提高了32.4%~104.8%,显著强化电渗排水(最高提升118%)与排盐效能(最高提升58.3%),其中EU组因电极转换形成双向离子通道,排盐效率最优;(2)转换电极注浆(EU)处理后的土体无侧限抗压强度较常规电渗法提升95.7%,水平强度差异率稳定于9.7%~11.1%,证实电极转换策略可突破传统电渗加固的空间异质性瓶颈。首次实现EICP与动态电极调控的有机融合,为盐渍土工程性质修复提供了兼具高效排盐与均匀加固的创新技术路径。

     

    Abstract: To address engineering issues caused by salt expansion damage and insufficient structural strength in sulfate saline soils, a method combining electroosmosis with enzyme-induced carbonate precipitation (EICP) was employed to comprehensively improve the engineering properties of sulfate saline soils. Comparative experiments were designed with three grouting methods: electrode-switching grouting (EU), non-electrode-switching grouting (EM), and direct grouting (EN), systematically exploring the synergistic mechanisms of grout migration, salt removal, and strength formation under electric field effects. The experiments utilized a potential difference to drive salt ions out of the soil with electroosmotic flow, while Ca2+ generated from EICP hydrolysis combined with CO32 at the cathode to form calcium carbonate cement, thereby improving the soil. The results showed that: (1) Grout injection increased the current by 32.4% to 104.8%, significantly enhancing electroosmotic drainage (up to 118%) and salt removal efficiency (up to 58.3%). The EU group, with its bidirectional ion channels formed by electrode polarity switching, achieved the highest salt removal efficiency. (2) The unconfined compressive strength of soil treated with electrode-switching grouting (EU) increased by 95.7% compared to conventional electroosmosis, with horizontal strength variability stabilized between 9.7% and 11.1%. This confirms that electrode-switching strategies can overcome the spatial heterogeneity limitations of traditional electroosmotic reinforcement. The study marks the first successful integration of EICP with dynamic electrode regulation, offering an innovative technical approach for saline soil engineering that combines efficient salt removal with uniform reinforcement.

     

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