Test And Analisis On The Hydraulic Conductivity Of Frozen Soil With Changing Porosity

The dissertation is based on the monitoring data of the typical monitoring area in Hulan district of Heilongjiang University Campus. Combining with the previous research and experience and analyzing the factors that affect the hydraulic conductivity of unsaturated permafrost, this paper takes the ice-containing rate and the sample dry density as the two control indices and to take the univariate frozen soil permeability coefficient measurement test respectively. Taking the ice-containing rate and the sample dry density as the single factor variable, and aiming at find out the hydraulic conductivity of unsaturated permafrost and the unclosed porosity, to conduct the research on the hydraulic conductivity of unsaturated permafrost testing, and to analyze and compare combining with the testing results.The dissertation relies on the projects of State Key Laboratory of Frozen Soil Engineering Fund Project: Study on Effects of Frozen Soil Characteristics on Permeability Coefficient(SKLFSE201310), the projects of Hydrology Bureau in Heilongjiang Province: Experiment and Analysis of The Snowmelt Infiltration’s Mechanism About Frozen Soil in Spring of The Cold Region(2014230101000411) and the subjects of National Natural Science Foundation of my tutor: Research on Hydraulic Characteristics of Frozen Soil and Its Influencing Mechanism on Snowmelt Infiltration in Cold Region(41202171). The main contents completed are as follows: to find out the basic characteristics of the sample soil in the typical monitored area(grain composition, dry density and temperature) by collecting and processing previously the data of typical monitoring area in Hulan campus of Heilongjiang University; through reading the related references and generalizing the completed results, this paper summed that the main factors that affect measuring the unsaturated hydraulic conductivity are the ice rate of frozen soil, dry density, temperature, grain composition, non-closed porosity and so on; after processing the sample soil, including filtering and separating, tightly closing, water-saturating, which taking the TST-70 permeameter, cryostat tank, electric oven thermostat blast as the main test instruments, this paper conducts systematic measurement tests of the permeability coefficient of unsaturated frozen soil, and analyzes and discusses the test results and points that: the permeability coefficient of unsaturated frozen soil and the non-closed porosity decrease as the ice rate of sample increases and slightly decrease as the dry density of the sample increases; initially proposes the design plan of the indoor devices which are used in measuring the permeability coefficient of unsaturated frozen soil, aiming at measuring the permeability coefficient and the non-closed porosity, the devices are divided into five models: environmental monitoring devices, storage devices of permafrost, pressure measuring devices, penetration liquid and timing devices.