粘性土(红土)中游离氧化铁含量对其工程地质性质的影响

通过试验, 本文就游离氧化铁在粘性土尤其是红土中富积含量的变化对土体工程地质性质产生的影响及其规律性做了初步研究。

EFFECT OF FREE FERRIC OXIDE CONTENT IN COHESIVE SOIL(LATERITE)ON ITS ENGINEERING GELOGICAL PROPERTIES

Cohesive soil contains much free ferric oxide, especially in laterite. The engineering geological properties of cohesive soil(laterite) are influenced by free ferric oxide content in it. In this paper, the author studys this problems by experiment. The main result is as follows:(1) Cohesive strength of cohesive soil (laterite) increased with increasing of free ferric oxide content. The cohesive force(C)and friction angle (Φ) are correlated with free ferric oxide content (FC). The correlation factor between C and FC is 0.78,and between and FC is 0.72. The compaction dry unit weight decreased with increasing free ferric oxide content (r=0.94). The relation between free expansion ratio and FC is negative correlation (r=0. 83). (2) The relations between plastic limit (Wp) and shrinkage limit (Ws) with FC are direct correlation (Wp-FC:r= 0. 901 Ws-FC:r=0.88).(3)The correlations between shrinkage ratio(Es) and shrinkage index (Is )wkh FC are not clear, but with increasing FC, their general trend is to reducte. (4)The liquid limit(WL) and plastic index (Ip ) are not correlated with FC (WL-FC: r=0.34 IP -FC: r=0.51). If making a concrete analysis of each group of soil samples,the result is not alike. Perphs the different form of free ferric oxide leads to this abnormal phenomena.