A COLUMN TEST FOR INVESTIGATING THE PERMEABILITY CHARACTERISTICS OF UNSATURATED LOESS

General loess slope deformation and destruction associated with surface water infiltration leads to the rise of ground water level. However, in-situ observation found the loess area, surface water infiltration depth is limited, the rain moist peak within 2meters in general. Under moist peak to the moisture content of a long between the underground water level is constant, so how is the surface water recharge of groundwater, has been controversial. To this end, the paper used in Zhengning county in Gansu province Q3 loess reshape unsaturated seepage characteristics of soil column experiment was carried out. In a 4m tall glass barrel preparation of soil samples, the soil column spacing according to certain insert moisture meter probe, uniform infiltration water in the top 1000mL of water a day, measured at a given time along the moisture content of soil column section. The results found that with the supplies the extension of time, the peak down, wet moist peak after the upper soil moisture content is almost the same, when moist peak reach the bottom of the soil column, the formation of groundwater level, and the phenomenon of field observation. This shows that the surface activity with the following, above the saturated zone, while the moisture content of soil unchanged, but there is a steady unsaturated seepage, it was the only one the loess area, the groundwater recharge mode.