长江口软土的次固结特性试验研究及应用

Experimental Study on Secondary Consolidation Characteristics of Soft Soil in Yangtze River Estuary

对长江口淤泥质软土进行一系列固结实验,研究了荷载、超固结比、土性指标等对软土次固结系数的影响,得出了该区域软土的次固结特性及不同土层的次固结系数。试验结果表明:次固结系数与荷载有关,且随着荷载的增大先增大后减小,最后趋于平稳;次固结系数与最大固结压力有关,且随着超固结比的增大而减小;次固结系数与压缩指数的比值近似为常数0.031;次固结系数与初始孔隙比及初始含水率呈线性关系。提出了一种考虑主次固结同时发生的沉降计算方法,并通过所得次固结系数对横沙围堤进行了沉降预测,与现场监测吻合较好。所提出的计算方法更符合工程实际需要,具有很好的实用价值。试验所得的相关参数及结论对研究长江口软土特性及后期工程的沉降预测具有一定参考意义。

A series of consolidation tests were conducted to study the secondary consolidation characteristics of muddy soft clay in Yangtze river estuary.Author researched the influence of load,over-consolidation ratio and soil indicators on secondary consolidation coefficient and got the secondary consolidation coefficient of different soil layers.The results show that the secondary consolidation coefficient which related to the load,increases at first and then decrease,and finally go towards stability along with the increasing of the load.The secondary consolidation coefficient relates to the maximum consolidation pressure and decreases along with the increasing of over-consolidation ratio.The ratio of secondary consolidation coefficient and compression index is approximately constant 0.031.The secondary consolidation coefficient has a linear relationship with initial pore ratio and initial water content.The paper proposes a new method that considered the simultaneous occurrence of primary consolidation and secondary consolidation to calculate the settlement,and the settlement prediction of the Hengsha dike by the secondary consolidation coefficient is in good agreement with the on-site monitoring.The proposed method is more suitable for engineering practice and has a good practical value.The related parameters and conclusions obtained from the research can provide references for the later engineering practices.