软土结构性及结构破损机理

Structural Characteristics and the Damage Mechanism of Soft Clay

通过对漳州和黄石地区2种结构性软土进行单向与等向压缩试验，根据原状样和重塑样的压缩曲线确定了先期固结压力和结构强度．研究表明，漳州软土结构应力比在1．1～1．2之间，黄石软土在1．2～1．3之间，说明在沉积过程中产生的结构屈服压力与上覆压力基本成正比．结构强度随埋深、试验的加荷间隔、加荷时间的增加而增大；由单向压缩试验曲线得到的结构强度大于等向压缩试验曲线得到的结构强度；卸载再加载过程对结构性强弱影响不大．计算得到漳州软土结构破损系数为17．7％，黄石软土结构破损系数为14％，说明黄石软土结构性略强于漳州软土．从微观角度解释了土的结构破损主要是由颗粒间的连接方式的改变与孔隙变化所引起的．

Zhangzhou and Huangshi soft clays were tested under uni-directional and isotonic compression loading. The pre-consolidation pressure and structural strength of the soft clays were determined from an analysis of the compression curves of both reconstituted and original soils. The structural stress ratio was found to be 1.1～1.2 for Zhangzhou and 1.2～1.3 for Huangshi clays. This shows that the yield pressure produced during the deposition process and the overburden pressure are proportional. Structural strength increased along with burial depth, loading interval and loading time. Unidirectional compression tests give a structural strength greater than the isotonic compression tests. Re-loading after unloading did not have a large effect on structural strength. The structural damage coefficients of Zhangzhou and Huangshi clays are 17.7 and 14 percent, respectively. From a microscopic perspective the damage was caused mainly by changes in the connection between soil particles and by changes in the pore structure.