压实过程对红黏土的孔隙分布影响研究

为研究压实作用对红黏土孔隙分布的影响,采用液氮冻干法对经过压力板仪脱至残余含水率后的压实试样进行干燥,继而利用孔隙仪测试其孔隙分布特征。结果表明,不同干密度试样的孔隙分布特征在孔径d10μm范围内差异性比较明显,干密度越大分布在该范围内的孔隙越少,但所有试样的大部分孔隙主要分布在孔径d0.1μm的范围内,并且分布密度十分相似。换言之,常规压实作用只能改变土体某一较大孔径范围内的孔隙,而对小孔径的孔隙改变不大,这也对于说明红黏土路基填料的压实,常规的压实作用对提高土体的压实度幅度有一定范围。

Research on effect of compaction on pore size distribution of laterite soil

To investigate the effect of compaction on the pore size distribution characteristic of laterite soil, the compacted soil samples which were firstly subjected to pressure plate to dehydrated to their residual water content were dried by liquid nitrogen freeze-drying method; and then the corresponding pore size distribution was measured. The results show that, among samples with different dry density, the differences of characteristics of pore size distribution are obvious in the case that the pore size is larger than 10 μm. And the greater the dry density is, the fewer the pores of soil in this scope. However, most of pores of samples are mainly distributed in the range where pore size is finer than 0.1 μm and their pore distribution density are almost the same, which means that conventional compaction of soil can only change the larger pore size, no significant change for the smaller one. This also indicates that the conventional compaction has a limit effect on the compactness of the roadbed which was filled with laterite soil.