海积软土渗透性变化及固结分析

如何提高软土地基固结沉降计算的准确性是当前急需解决的难题之一。海积软土性状特殊,具有固结变形量大,固结过程中压缩性、渗透性发生较大变化的特性。针对海积软土,研究其固结过程中渗透固结性质的变化规律是提高其地基固结沉降计算准确性的关键。本文以深圳前海湾海积软土为例,通过试验和分析,对目前常用的软土渗透性计算公式是否适用于海积软土进行了检验,提出了适合海积软土渗透系数计算的经验公式,在此基础上进行了考虑固结系数变化时的一维固结计算,用试验数据对计算得到的固结曲线的合理性进行了验证,并将计算结果与工程中基于Terzaghi固结理论的分析结果进行了比较。试验结果和计算结果表明,所提出的渗透系数计算公式对海积软土合理,方法实用;海积软土固结过程中固结系数变化较大,应发展考虑固结系数变化时的固结分析方法;工程中进行海积软土固结分析时应根据实用固结压力情况及不同的试验方法合理地取用固结系数。

Analysis on Permeability Variation and Consolidation of Marine Deposit

How to improve the accuracy of consolidation settlement calculation for soft soil ground is currently one of the urgent and difficult problems. The marine soft soil has peculiar properties, and during consolidation process it has large deformation and rather great changes in compressibility and permeability. For marine deposit soil, to take special researches on its permeability and consolidation behaviors during consolidation process is a key issue to enhance the accuracy of consolidation settlement calculation. Taking the marine deposit soil in the Former Shenzhen Bay for example, the permeability formulas commonly used are checked for that whether they are suitable for marine deposit soil, and an empirical formula is offered for permeability calculation of marine deposit soils through experiment and analysis. Based on the former work, one dimensional consolidation calculation is carried out considering variable coefficient of consolidation, and the rationality of the calculating results is checked by test data, and the calculation is also compared with Terzaghi theory which is widely used in actual projects. As the experiment and analysis result shows, the formula of permeability calculation is reasonable and practical; the consolidation coefficient of marine soft soil varies widely during consolidating, and it is necessary to develop analysis methods with considering variable consolidation coefficient; when taking consolidation analysis on marine soft soils in actual projects, the consolidation coefficient should be adopted reasonably by considering pressure situation and different test method.