干-湿循环条件下压实宽级配砾质土SWCC研究

摘要

It revealed the water conservation function of geo-textiles betonies layer in composite impervious system of landfill site wide grading grav-elly soil as a protective layer,used pressure membrane method to determine the compaction of wide grading gravelly soil dehydration soil water char-acteristic curve after dry-wet cycles and summed up the change laws of soil water characteristic curve of the compaction wide grading soil samples with the increase of the dry-wet cycles. Experimental results show that in the first 3 times determination to take off the wet of SWCC,the saturated moisture content of soil sample obviously increases with the number of dry-wet cycles,but the increase rate decreases,after 4 times to take off the wet,saturated moisture content decreases,but still significantly greater than the samples without the dry -wet circulation;The intersection of the second to the fifth dehydration curve and the first dehydration curve is moving to the left with the increase of dry-wet cycles;In the end of the curve, under the same matric suction,with the increase of dry-wet cycles,moisture content significantly decreases;After the matrix suction of 50 kPa, SWCC overall down with the increase of dry-wet cycles,but the change is getting smaller gradually.%采用压力膜仪法测定了压实宽级配砾质土干-湿循环后的脱湿土壤水分特征曲线，总结了压实宽级配土样随干-湿循环次数的增加其土壤水分特征曲线的变化规律。试验结果表明：第1次至第3次脱湿SWCC测定中，土样的饱和含水率随着干-湿循环次数的增加明显增大，但是增加幅度逐渐减小，经第4次脱湿后，饱和含水率下降，但仍明显大于未经干-湿循环的土样；第2次至第5次脱湿曲线与第1次脱湿曲线的交点随着干-湿循环次数的增加不断向左移动；在曲线末端，相同基质吸力下随着干-湿循环次数的增加，含水率明显减小；在基质吸力大于50 kPa时，SWCC随着干-湿循环次数的增加整体下移，但变化幅度逐渐减小。