海水环境下水泥土强度衰减过程室内试验研究

发布时间：2019-05-24 13:23

【摘要】：针对滨海相软土场地形成的水泥土的强度衰减问题,采用天然海水作为腐蚀介质对水泥土进行一维浸泡试验,通过微型贯入试验、扫描电镜(SEM)试验、能谱(EDS)分析、X射线衍射(XRD)试验、离子含量及p H值测试等多种试验手段研究水泥土强度的分布规律和衰减过程。根据贯入阻力随贯入深度的变化规律将水泥土分为劣化层和未劣化层。结果表明:随着养护时间的增长和水泥掺入比的减小,水泥土的劣化深度不断增大,至360 d时最大劣化深度达到8.7mm;与未劣化层相比,劣化层的孔径增大,孔隙增多,水泥水化产物减少;水泥土的p H值和Ca~(2+)含量随着试样深度的增大而增大,Mg~(2+)、SO_4~(2-)、Cl~-含量随试样深度的增大而减小。经海水养护后,水泥土中Ca~(2+)含量沿试样深度方向的分布规律与强度变化规律相似。在本试验条件下,水泥土的强度衰减是海水中侵蚀性离子抑制水泥土强度增长过程和促使水泥土强度降低过程的共同结果,在此过程中Ca以离子形式溶出,最终导致水泥土的劣化深度不断增大。
[Abstract]:In order to solve the problem of strength attenuation of cement-soil formed in coastal soft soil site, one-dimensional immersion test of cement-soil was carried out with natural seawater as corrosion medium. through micro-penetration test, scanning electron microscope (SEM) test and energy spectrum (EDS) analysis, X-ray diffraction (XRD) test, ion content test and pH value test were used to study the distribution and attenuation process of cement-soil strength. According to the variation of penetration resistance with penetration depth, cement-soil is divided into degraded layer and undegraded layer. The results show that with the increase of curing time and the decrease of cement mixing ratio, the deterioration depth of cement-soil increases, and the maximum deterioration depth reaches 8.7 mm at 360 d. Compared with the undegraded layer, the pore size of the degraded layer increases, the pores increase, and the hydration products of cement decrease. The pH value and Ca~ (2) content of cement soil increased with the increase of sample depth, while the contents of Mg~ (2), SO_4~ (2 -) and Cl~- decreased with the increase of sample depth. After seawater curing, the distribution of Ca~ (2) content in cement-soil along the depth of the sample is similar to that of strength. Under the experimental conditions, the strength attenuation of cement-soil is the common result of the inhibition of cement-soil strength growth by erosive ions in seawater and the reduction of cement-soil strength. In this process, Ca is dissolved in the form of ions. Finally, the deterioration depth of cement-soil is increasing.
【作者单位】：中国海洋大学海洋环境与生态教育部重点实验室;中国海洋大学环境科学与工程学院;山东科技大学;
【分类号】：TU411

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