海水浸泡下水泥土强度衰减室内试验研究

Experimental study on strength deterioration process of cement stabilized soil with seawater immersion

通过对不同浸泡时间和不同水泥掺入比的水泥土进行微型贯入试验、X线衍射(XRD)试验、扫描电子显微镜(SEM)试验及化学分析试验研究一维浸泡试验中水泥土的强度衰减过程和劣化机理。研究结果表明:水泥土的劣化深度随海水浸泡时间的增长逐渐增大,随水泥掺入比的增大逐渐减小。对于浸泡360 d的水泥土,水化产物C—S—H的峰值随着深度的增大而增大,与水泥土强度变化趋势一致。在0~10 mm深度区域内,水泥土的孔隙增多,孔径增大,Ca质量分数明显降低,在10 mm以下部分纤维状及网状的生成物增多,出现明显的絮凝现象。水泥土试样由浅到深,Ca^(2+),SO_4^(2-)和CO_3^(2-)的质量分数呈增大趋势,Mg^(2+),Cl^-和HCO_3^-的质量分数呈减小趋势。

Micro cone penetration tests, X-ray diffraction （XRD） phase tests, scanning electron microscope （SEM） tests and chemical component analysis tests were conducted to simulate and study the strength degradation process and deterioration mechanism of cement stabilized soil with different cement ratios and different curing time in marine environment. The results show that the deterioration depth of cement stabilized soil increases with the increase of time and decreases with the increase of cement ratio. As for the cement stabilized soil immerses in seawater for 360 d, the peak value of C--S--H increases with the increase of depth, and it is consistent with the change trend of strength of cement stabilized soil. The porosity and their apertures increase at the depth of 0-10 ram. At the same time, the mass fraction of Ca decreases obviously. The fibrous and mesh chemical products in the sample link the soil particles together, and flocculation phenomenon appears obviously below the depth of 10 mm. The mass fractions of calcium ions, sulfate ions and carbonate ions in the cement stabilized soil have a tendency to decrease from deep to shallow. However, the mass fractions of magnesium ions, chloride ions and bicarbonate ions gradually decrease with the increase of depth.