海相软土压缩特性的试验研究

对不同取样方式得到的上海、江苏地区海相软黏土的原状样和重塑样进行了单向压缩和等向压缩试验，分别得到各自的压缩曲线、压缩指数 和回弹指数 。通过比较原状样、重塑样的归一化压缩曲线的差异，确认了结构性对软黏土压缩特性的影响。把屈服应力后的压缩曲线外延至10 kPa时的孔隙比定义为参考孔隙比 ，用于简单量化土的组构。根据多次单向压缩试验结果得到的压缩指数 ，建立了原状样和重塑样的压缩指数 与孔隙比 或参考孔隙比 的相关方程，并通过单向、等向压缩指数的比较，认为此方程也适用于等向压缩试验结果。根据原状、重塑样压缩指数 与参考孔隙比 具有基本相同关系的结论，对原状样的结构屈服特性进行了探讨，认为原状样在压力大于结构屈服应力后，胶结已基本破坏，原状样和重塑样压缩特性差异主要是由组构的差异引起的。该研究成果，尤其是压缩指数 与参考孔隙比 的相关方程，可为工程提供重要的参考。

Experimental study of compression behavior of marine soft clays

A series of one-dimensional and isotropic compression tests have been carried out on undisturbed and remolded samples of marine soft clay taken from Shanghai and Jiangsu, with different sampling methods. The compression curves, compression index , and swell index are obtained from the tests. According to the normalized compression curves of undisturbed and remolded samples, the effect on compression characteristics of the soil structure is confirmed. The compression curves after the yield stress are extended to determine a reference void ratio which is used to quantify the fabric simply. Based on the compression index obtained from oedometer tests, the correlation between the compression index and void ratio e10 or reference void ratio are obtained. From the compression index between oedometer and isotropic tests, it is shown that they are the same on the whole, so the relationship obtained from the oedometer tests can be used for isotropic test results. In terms of the same relationship between the compression index and the reference void ratio between undisturbed and remolded samples, the characteristics of yielding of structure are discussed. The conclusion that the consolidation pressure is larger than the structure yielding stress, most of the bonding is broken, the difference of compression characteristics is caused by the difference in the fabric, is obtained. The conclusions especially the relationship between the compression index and reference void ratio provide important reference value for engineering practice.