上海第④层淤泥质黏土的次固结试验研究

Experimental Study on Secondary Consolidation of the Fourth Layer Muddy Clay in Shanghai

上海滨海平原地基土遍布第④层灰色淤泥质黏土,常见厚度5~10 m,是主要的软弱土层。对于具有明显流变特征的黏土,次固结变形是产生工后沉降的主要原因,不容忽视。为了研究该层土的次固结,进行了10组原状土样的次固结试验。试验表明:该层土的次固结系数在4.14×10^(-3)~9.88×10^(-3)之间,同时与压缩指数的比值范围为0.017~0.028,说明次固结系数与压缩指数基本呈线性关系。研究成果对第④层淤泥质黏土的次固结特性的理解有一定的指导意义。

The foundation soil of the coastal plain in Shanghai is covered with the fourth layer of gray muddy clay.Its thickness is often 5~10 m.It is mainly weak soil layer.For the clays with obvious rheological characteristics,the secondary consolidation deformation cannot be ignored,which is the main cause of post-construction settlement.In order to study the secondary consolidation of this soil layer,the secondary consolidation tests of 10 groups of undisturbed soil samples are carried out.The test show that the secondary consolidation coefficient of this soil layer is between 4.1410^(-3)~9.8810^(-3),and at the same time,the range of the ratio to the compressibility index is 0.017~0.028,which indicates that the secondary consolidation coefficient and the compressibility index are basically linearity.The research results have certain guiding significance for the understanding of the secondary consolidation characteristics of the fourth layer muddy clay.