Experimental Study On Permeability Of Unsaturated Remodeled Soil

Rainfall and irrigation are important factors in the formation of geological disasters.The change of water content in the soil will directly or indirectly affect the shear strength of soil and induce a series of disasters.Therefore,the study of infiltration of unsaturated soils becomes the focus of experimental soil mechanics In this paper,through the selection of three kinds of test soil materials,first of all the selected soil moisture sensor calibration test results analysis,probe installation method of measurement range,through the experimental study to determine the appropriate fitting formula and the best sensor installation.And the debugging and improvement of the infiltration model test equipment are summarized.A set of effective test methods are discussed,and the study of the permeability test is discussed.The migration law of water and the migration law of wet front are discussed.Calculation of Permeability Coefficient of Saturated Soil.Get the following conclusions:1.The different depths of the sensor probe form a probe portion that is in contact with the air or has a gap between the probe and the soil sample or the proximity of the probe to the non-soil sample,directly or indirectly affecting the sensor measurements;5TE type sensors were used to test three different soil properties,different dry density and different water content.The fitting curves of dielectric constant and volume water content of three soils were established.The EC-5 sensor was discussed in two different The influence of the supply voltage on the output voltage was established.The fitting curves of the linear output voltage and volume water content of two soils were established.2.The results show that the actual measurement range of the two kinds of sensor probe installation is lower than the theoretical measurement range,and the vertical installation of the horizontal installation of the measurement Large range.According to the measurement range of 5TE,5TM and tensiometer sensors,the wetting front migration of the infiltration test can be predicted,in which the prediction of the tensiometer is more accurate.3.The initial water content of soil samples,infiltration process can be observed significantly changes in the wet front of the phenomenon.The increase of the migration velocity of the loess has a smooth increasing trend with the infiltration time,which can approximate the simple power series function.However,the migration of the wet-front is not consistent with this characteristic.The relationship between the depth of migration and the infiltration time is transformed from a linear relationship to a nonlinear relationship.4.The infiltration test results show that the infiltration rate of the infiltration process of the soil undergoes a rapid decline,a slow decrease,and a stabilization of the three stages.In the initial low water content,the internal porosity of the soil is large,and the flow channel forms a dominant channel in the pore.Then,in the short period of time,the infiltration rate of the dominant channel is rapidly decreasing.And the initial high water content of the soil within the pores of the smaller,in the infiltration test process,the soil part of the gas will be surrounded by water,so that the soil within the pores of the dominant channel to reduce or block,hinder the infiltration of water The infiltration rate is small and remains essentially stable.It is found that the saturation of the loess is more than 75%,and the average saturation of the soil with lower initial water content is slightly lower than that of the initial water content.5.The lower the initial water content of soil samples in the infiltration process,the superficial soil in the more easily escape the gas,and the greater the perturbation of the infiltration of soil,and the greater the frequency of pressure fluctuations,resulting in air pressure is difficult to achieve stability status.In the infiltration test with low initial initial water content,the initial flow was not formed in the low initial water content test of the loess margin.In addition,the rhizosphere in the initial water content was lower,The cumulative infiltration curve showed a significant step-like change,in the initial water content of the infiltration test,the cumulative infiltration is a curve,and no obvious ladder-like changes,and Mao Su Sha sand infiltration test,the cumulative The infiltration curve is an oblique line change.