Experimental And Theoretical Research Of Hydraulic Properties Of Root-containing Soil

Long-term service performance of landfill field final cover layer has caused more and more attention, cover layer under the action of wet and dry cycle will crack, resulting in enhancement of seepage ability of layer covers. Final cover layer usually grow plants, plants have certain restrictions on fracture. In this paper, we will study the hydraulic characteristics of the soil containing the root and the crack.In this paper, the hydraulic characteristics of soil with plant roots and fractured are studied by using the soil column test. The test apparatus can be used to get the soil samples containing the root and can be directly used to do the soil column test. The experimental apparatus includes three parts, the precipitation device, the main body of the soil column, and the drainage collecting device.The test device was designed by self- design, and the soil samples were obtained from the outdoor test site. The soil column infiltration test was carried out and the test results were compared and analyzed. Indoor soil column infiltration test was divided into four groups, soil samples respectively remolded sample, excluding roots with the fracture of outdoor field soil samples, containing bermudagrass root system of outdoor field soil samples, containing vetiver grass roots outdoor field soil samples. The collecting time of end seepage of four kinds of soil samples under the same conditions of rain is different, the time we get seepage is 57.5 hours later for remolded soil samples, for outdoor field soil samples does not contain roots with the fracture it is 12 hours later, for outdoor field soil samples with roots of Cynodon dactylon it is 20 hours later, for outdoor field soil samples containing vetiver grass roots it is 1.3 hours later. Compared with outdoor without root soil, roots of bermudagrass can improve impervious performance of covering layer and vetiver grass roots make outdoor coverage layer impervious performance weakened. Comparison of each soil samples of different depth in the same matric suction permeability coefficient can be found that vetiver grass roots of covering layer permeability influence depth beyond 14 cm, Bermuda grass and fissure of Overburden Depth does not exceed 9 cm thickness.According to the permeability coefficient of the test, the formula for calculating the unsaturated permeability coefficient is established. Parameters of the model are directly related to the root parameters.