Test Study On Hysteresis Of Water-Sand Mixture Flow In Rock Fracture

The constitutive variables’ multiple-valued correspondence is a common phenomenon in nature. When the hysteresis effect is considered, constitutive relation reflects the objective laws in the natural world more accurately. In this paper, the research methods of hysteresis effect in the electromagnetism, solid mechanics and some others subject are used to research the hysteresis phenomenon of the penetration of water-sand in the rock fracture. A test system of water-sand permeates in the rock fracture is used to finish the test of water-sand mixture radial permeates in the rock fracture, we get four typical hysteresis curves, define the hysteresis parameters corresponding to the four typical hysteresis curves. By analyzing the fracture width,particle size of sand and sand mass concentration’s influence to hysteresis parameters,discussing the transformation condition of hysteresis curve’s shape, explaining the reasons for hysteresis phenomenon, and we get the following research results:(1) Seepage velocity lagging behind the pressure gradient’s rock fracture water-sand penetration test method is proposed based on the penetration rate’s distribution on the fracture height direction.(2) The I, II, III and IV four types water-sand seepage velocity-pressure gradient curves are gotten and four kinds hysteresis curves’ s geometry characteristic parameters are defined by changing the fracture width, particle size of sand and sand mass concentration.(3) The transformation condition of hysteresis curve’s shape is discussed by comprehensive factorial test.(4) The fracture width, particle size of sand and sand mass concentration’s influence to IV seepage velocity-pressure gradient hysteresis curve’s shape parameters(hysteresis parameters) is gotten by single factor test.(5) Based on the relationship between seepage velocity and penetration rate, the reasons for hysteresis phenomenon of the penetration of water-sand in the rock fracture are analyzed from the view of sand deposited on the surface of the rock fracture, the change of movement manner of water-sand in the rock fracture and the viscoplasticity of water-sand mixture.