Experimental Study On Sub-erosion In Unsaturated Of Dingbian Loess

Plateau is the natural testing ground to carry out the research of hazard effects of human activities on the environment.In recent years, With the implement of Western Development Strategy, social economy in the Loess Plateau develops rapidly, human activities increasing frequently, thus, engineering loess landslide hazards growing seriously, which becomes an important factor blocking economic development of the Loess Plateau. It is the disasters caused by the change of water that is the most topical and hinders the economic development of loess plateau most in many loess landslide disasters. This paper mainly studies about the erosion and penetration of water to remolded loess. Choose Huangwan country in Dingbian county as the subject. Carrying out experiment with T5×tension meter to study the property of unsaturated soil water. Apply penetration and erosion equipment to do corresponding experiment and control water content and flow while testing. With the analyzing of scour rate in different initial water content and different initial scour flow. We can conclude as follows:1.Introduce the saturation and use method of T5 x tension meter in detail. Mainly elaborating and introducing the mechanism of how to test SWCC rapidly. Use this kind of tension meter to test the unsaturated soil properties of loess in Dingbian and compare the SWCC got with pressure plate reader testing system. Adopt the three kinds characteristic function model of soil water(Gardner、Van Genuchen、Fredlund and Xing) to fit the SWCC of loess in Dingbian. Estimate permeability coefficient of unsaturated loess in Dingbian.2. The process curve of clay content obtained in penetration and erosion test is a direct reflection of erosion rates and variation. The method to filter and fix clay content: method of measuring practical, hydrometer method, anti algorithm of total solution density. Compare the advantages and disadvantages of the three methods. Mainly deriving the formula of the clay content which adopts the B species method of anti algorithm. Conclude that hydrometer method can replace the method of measuring practical to obtain the clay content faster and more convenient.3. Reveal the relationship with two factors(initial water content of preparatory sample and initial flow of erosion): The flow has an inverse linear relationship with the erosion rate and water content of preparatory sample). That is, with the increase of water content in preparatory sample, the erosion gradually decreases; the greater the flow, the effects of water erosion is more obvious. In different head while under same condition of flow, the effect of water erosion performance no significant difference.