The Study Of Accumulation Of Gravel Soil Element Mesoscopic Parameters-Macroscopic Mechanical Parameters Correlation

Accumulation of gravel soil is a kind of soil-rock-mixture, as a typical binary medium,it’s the complex causes of formation of the low strength of soil and High strength of rock. Composed of accumulation of gravel soil slope and landslides are widely distributed in China(especially in the southern area), It can easily cause the engineering landslide or collapse, bring huge economic losses and casualties.More and more domestic and foreign scholars research on the mechanical properties and deformation mechanism of soil-rock-mixture,and In the past indoor test or outdoor in-situ test were the main way to research on them. With the emergence of discrete element software, provides a reliable platform for the numerical simulation of soil-rock-mixture discontinuous medium,and more and more research scholars in favour of Numerical simulation test,because it ‘s cost is relatively low and it’s accuracy can be guaranteed.But, before using the discrete element software to numerical simulation,it is necessary to find the mesoscopic parameters which is reflect the macroscopic properties of material accuracily. Because there are many factors between mesoscopic parameters and macroscopic mechanical parameters of material itself which is difficult to control.Furthormore, nonlinear obviously between these factors,so it is difficult to get relationship betweenthem.Mesoscopic parameters calibration, generally obtained by trial and error method, and this process need to spend a lot of time and energy.In this paper, based on the laboratory test of the Accumulation of gravel soil of zhao shan,using the discrete element software PFC3 D generated 1:1 accumulation of gravel soil numerical model, which had different shape stone and its corresponding micro parameters is obtained by calibration(relative error control within 10%).Changing micro parameters had been discussed quantitatively its relationship with macroscopic mechanical parameters( cohesive force and internal friction Angle),got more mesoscopic parameters and the cohesive force, internal friction Angle equation,furthermore its reliability had been verified. Main conclusions are as follows:(1)The relationship of cohesive force with contact cohesive force,grain friction coefficient was of linear regression; At the same time,influenced by bond ratio M= /c c? ? also, when M< 1, the cohesive force of linear increase with the increase of M,and when M≥4, cohesive force to be stabilize.(2)The relationship between internal friction Angle and friction coefficient ofparticles is logarithmic,and parabola relationship to the contact adhesive power.( 3) The joint relation of the mesoscopic parameters and macroscopic mechanical parameters were gained,and it had passed the reliability test and verify.The joint relation of the mesoscopic parameters and macroscopic mechanical parameters were gained based on laboratory test results of moisture content of7%,apply the formula in the mesoscopic parameters calibration using the indoor test results of the 9%, 11% and 13% moisture content to verify it’s accuracy.According to the c 、? gotted by indoor test with moisture content of 9% 、 11% and 13%,used the micro- macro parameter equation to calculate the micro parameters. And its virtual- indoor test results of relative error was within 10%. Fine- macro mechanics equation were reliable,and it can provide the reference to subsequent soil-rock-mixture micro parameters calibration of virtual experiment.