非饱和重塑Q_2和Q_3黄土的渗水特性研究

随着西北大开发战略的实施,工程中涉及的Q2黄土及其重塑土日益增多。为了研究非饱和重塑Q2黄土的渗透特性及其和Q3黄土渗透特性的差异,对重塑Q2和Q3黄土分别做了4个干密度的水平土柱入渗试验;采用MP-406水分计及数据采集系统量测不同断面处体积含水率随时间的变化情况。实验研究结果表明:相同干密度的重塑Q2和Q3黄土渗水特性存在较大差异。在相同饱和度情况下,重塑Q3黄土扩散率大于重塑Q2黄土,并且随着饱和度的增大这种差异逐渐减小。不管是重塑Q2黄土还是Q3黄土,饱和度达到0.6左右时,扩散率近似由两条直线段组成;对于重塑Q3黄土,当饱和度低于0.6时,干密度的不同对扩散率影响不大;当饱和度高于0.6时,扩散率存在较大差异;但对于重塑Q2黄土,此规律不明显。

Permeability of Unsaturated Remolded Q2 and Q3 Loess

With the implementation of the Northwest development strategy ,engineering involved Q2 loess and its remolded loess are increasing .In order to study the permeability of unsaturated remolded Q2 loess and the differences of permeabili-ty between remolded Q2 and Q3 loess ,four dry density of horizontal soil column infiltration test were performed;MP-406 water meter and remote monitoring system were adopted to monitor volumetric water content in different sections .The ex-periment results show that:the permeability of the same dry density of Q2 and Q3 loess is quite different ,in the same sat-uration ,Q3 loess diffusion coefficient is greater than Q2 loess ,and with the increasing saturation of this difference gradu-ally decreases;for both Q2 and Q3 loess ,when saturation reached about 0 .6 ,the diffusion coefficient is approximated by two straight segments ,for Q3 loess when saturation is less than 0 .6 ,different dry density has less effects on diffusion co-efficient ,when saturation is higher than 0 .6 ,there is a large difference in diffusion coefficient .For Q2 loess ,this law is not obvious .