电石渣改良路基过湿土的微观机制研究

 为揭示电石渣改良路基过湿土的强度增长机制，通过无侧限抗压强度、酸碱度、压汞和热重分析试验，从微观角度出发，探讨改良土强度与pH值、孔径分布、火山灰反应产物含量的内在联系，并与石灰改良土进行比较。结果表明，电石渣改良路基过湿土早期强度与生石灰改良土接近，而后期强度为生石灰改良土的1.05～1.16倍；电石渣细粒含量约为生石灰的1.72倍，比表面积大5倍，可保障电石渣与土颗粒接触更充分；电石渣活性Al，Si成分含量约为生石灰的1.71倍，且电石渣改良土pH值可维持在12.4～12.6(而生石灰改良土pH值低于12.4)，为火山灰反应提供较好的碱性环境，水化反应更持久；28和120 d龄期时，电石渣改良土的火山灰反应产物含量约为生石灰改良土的1.06和1.10倍，且微孔隙(＜0.007 μm)和小孔隙(0.007～0.900 μm)的体积百分比之和分别约为生石灰改良土的1.05和1.23倍，结构更致密。

MICROMECHANISM OF OVER-WET CLAYEY SOILS STABILIZED BY CALCIUM CARBIDE RESIDUES

To illustrate the factors controlling the strength development of calcium carbide residue(CCR) and quicklime stabilized over-wet clay soils，a series of laboratory tests including unconfined compression，soil pH measuring，mercury intrusion porosimetry(MIP) and thermo gravimetric analysis(TGA) were conducted to quantify the relationships between the unconfined compressive strength with the soil pH，the pore size distribution and the content of pozzolanic reaction product. The experimental results show that the strengths of CCR are similar to ones of quicklime stabilized soils at early stage and are 1.05 to 1.16 times higher at late stage. The fractions of clay particles，the specific surface area(SSA)，and the contents of reactive silica(Si) and alumina(Al) of CCR rebound are 1.72，5 and 1.71 times those of quicklime respectively. The pH values of the CCR stabilized soil are approximately 12.4 to 12.6 with the curing times of 28 to 120 days，which is in favor of the pozzolanic reactions between the CCR and soil particles. In addition，the pozzolanic reaction products in CCR stabilized soil are 1.06 and 1.10 times that of the quicklime stabilized soil. The sum of volumes of micro(＜0.007 μm) and small (0.007–0.900 μm) pores of the CCR stabilized soil are 1.05 and 1.23 times that of the quicklime stabilized soil when the curing times are 28 and 120 days.