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 mu m. 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 mu m 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.