动、静荷载预压密后土压缩性状的对比研究

COMPARISON OF COMPRESSION BEHAVIOR OF SOIL AFTER PRE-DENSIFICATION BY STATIC OR DYNAMIC LOADS

在侧限条件下,对物理性质相同的土分别采用静力和冲击作用产生相同的预压密,对预压密后的土样进行高压固结试验,对比研究压密程度相同但成因不同的预压密后土的压缩曲线、前期固结压力和压缩指数。结果表明,相同预压密的土,压缩后土的压缩指数相近,与预压密的成因无关。而压缩曲线和前期固结压力则因土类而异,经历相同预压密后,不饱和粉质黏土和粉砂的压缩曲线及不饱和粉质黏土的前期固结压力只与预压密量相关,与成因无关;但对饱和粉质黏土,静力预压密将产生超固结状态,前期固结压力与预压密量正相关;而冲击预压密产生的超固结则不明显,前期固结压力也与冲击预压密量关系不大。

High-pressure oedometer tests were conducted on soils pre-densified with the same amount of vertical deformation formed by static load and impact load under confined compression conditions. Compaction curves, preconsolidation pressures and compression indexes of same pre-densification deformation soil formed in different way were comparatively investigated. The results showed that compression indexes of same pre-densification soil were close and irrelevant to the cause of pre-densification; compression curves and preconsolidation pressures were varied with soil types. For lower saturated soils, compression curves and preconsolidation pressures after compression were only relevant to pre-densification deformation amounts and irrelevant to the cause of pre-densification in same pre-densification condition; for nearly saturated soils, over-consolidated states were formed due to static loads and preconsolidation pressures increased with the amounts of pre-deformation; but over-consolidation states formed by impact load were not obviouse, preconsolidation pressures were irrelevant to pre-densification deformation formed by impact load.