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为深入了解软土蠕变机制,开展了上海淤泥质黏土的一维固结蠕变试验、结合水测试试验和扫描电镜(SEM)试验,定量分析了固结蠕变过程中结合水和微结构的分阶段变化规律。结果表明:p<σ_k时主要是自由水的排出,宏观表现为衰减蠕变过程;p>σ_k后,渗透结合水逐渐转化为自由水排出,蠕变变形和等速蠕变率明显增大。蠕变过程由渗透结合水主导,随着结合水排出土的结构逐渐固化,含水率随荷载增加呈指数型衰减,存在固结-蠕变耦合效应。松散的骨架-絮凝结构演变为紧密的团聚-絮凝结构,颗粒在经历了蠕变调整之后定向性降低,小孔隙数量大量增加,孔径<1μm的小孔隙组占优。存在荷载、结合水与颗粒的响应机制,其结果可以较好地解释工程现象。
In order to further understand the creep mechanism of soft clay, a one-dimensional consolidation creep test was carried out in Shanghai silt clay. The water test and scanning electron microscopy (SEM) tests were combined to quantitatively analyze the water- The phased changes. The results show that: p <σ_k is mainly the discharge of free water, macroscopical manifestation of decay creep process; p> σ_k, osmotic water gradually transformed into free water discharge, creep deformation and constant rate creep rate increased significantly. The creep process is dominated by infiltration of bound water. As the structure of the discharged water from the bound water gradually solidifies, the moisture content decays exponentially with increasing load, resulting in the consolidation-creep coupling effect. The loose framework-flocculation structure evolved into a compact agglomeration-flocculation structure, the orientation of the particles decreased after creep adjustment, the number of small pores increased greatly, and the small pores group with diameter <1μm dominated. There is a load, combined with the response mechanism of water and particles, the results can better explain the engineering phenomenon.