云南洗石沟泥石流的颗粒流模型研究
发布时间：2018-11-24 09:23
【摘要】：本文的工作围绕泥石流颗粒流模型的建立和分析展开,调查了洗石沟的概况,在泥石流堆积区实地取样后带回实验室进行测试,得到了泥石流堆积物的物理特性与力学特性。 对比了目前各种泥石流数值模型的特点,发现颗粒流模型能够更好地还原泥石流的过程。依据颗粒流接触力学模型选择了恰当的接触本构,同时结合试验结果计算出了当地的岩石碰撞回弹系数。根据所选择的接触本构确定了的颗粒流细观参数,建立了PFC-2D的直剪试验模型与岩石碰撞回弹模型,按照室内试验结果与计算得到的岩石碰撞回弹系数对细观参数进行标定。随后在PFC-2D中建立了泥石流的颗粒流模型,使用Excel将泥石流坡道二维形态导入到PFC-2D中。使用HIST命令记录检测石块的速度与位置变化趋势,使用LOGFILE命令记录某一时刻所有颗粒的位置与速度,并给出了数据处理的方法。 首先依据泥石流形态变化进行分析,从宏观上看,泥石流可分为一个大的阵流与若干较小阵流,泥石流前端刚好进入堆积区时整体的变化最为激烈,随后运动逐渐衰减,发现泥石流趋于停止时堆积区固体物源呈稳定角度堆积。然后分别基于监测石块的方法与类Largrange方法分析,结果基本一致。泥石流前端进入堆积区能量减小后,其余部分泥石流也会受到影响。根据泥石流萨维奇数与温度的分布可知,泥石流内部流态较复杂,变迁十分突然,大都处于快速流与慢速流两种极端状态。运动中的泥石流前端运动较为激烈,颗粒碰撞频繁、能量传递较大,碰撞作用占优；处于中部的泥石流相对稳定,惯性作用占优,碰撞与能量传递很少；尾部的泥石流则又处于激烈状态,与前端类似,碰撞作用占优；堆积区的泥石流却又较为稳定,也是惯性作用占优。
[Abstract]:This paper focuses on the establishment and analysis of debris flow model, investigates the general situation of rock washing ditch, takes samples from debris flow accumulation area and brings them back to the laboratory for testing, and obtains the physical and mechanical properties of debris flow deposits. The characteristics of various numerical models of debris flow are compared and it is found that the particle flow model can better reduce the process of debris flow. According to the contact mechanics model of particle flow, the proper contact constitutive model is selected, and the local rock collision resilience coefficient is calculated according to the experimental results. According to the selected contact constitutive parameters, the direct shear test model of PFC-2D and the rock collision springback model are established, and the mesoscopic parameters are calibrated according to the indoor test results and the calculated rock impact springback coefficient. Then the particle flow model of debris flow is established in PFC-2D, and the two-dimensional shape of debris flow ramp is introduced into PFC-2D by Excel. Using HIST command to record and detect the change trend of rock velocity and position, using LOGFILE command to record the position and velocity of all particles at a certain time, and the method of data processing is given. First of all, according to the morphological changes of debris flow, the debris flow can be divided into a large array flow and a number of smaller array flows. The overall change of debris flow is the most intense when the front end of the debris flow just enters the accumulation area, and then the motion gradually attenuates. It is found that the solid source of debris flow tends to stably accumulate at an angle when the debris flow tends to stop. Then the method based on monitoring stone and Largrange method are analyzed, and the results are basically consistent. When the energy of the front end of debris flow into the accumulation area decreases, the other part of debris flow will also be affected. According to the distribution of Savage number and temperature of debris flow, the internal flow state of debris flow is more complex, the transition is very sudden, most of them are in two extreme states of fast flow and slow flow. The debris flow in the middle of the debris flow is relatively stable, the inertial action is dominant, and the collision and energy transfer are very few, and the debris flow in the middle of the debris flow is relatively stable, with frequent particle collisions and large energy transfer. The debris flow in the tail is in a fierce state, similar to the front end, the collision is dominant, but the debris flow in the accumulation area is stable, and the inertial action is dominant.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.23
本文编号：2353126
[Abstract]:This paper focuses on the establishment and analysis of debris flow model, investigates the general situation of rock washing ditch, takes samples from debris flow accumulation area and brings them back to the laboratory for testing, and obtains the physical and mechanical properties of debris flow deposits. The characteristics of various numerical models of debris flow are compared and it is found that the particle flow model can better reduce the process of debris flow. According to the contact mechanics model of particle flow, the proper contact constitutive model is selected, and the local rock collision resilience coefficient is calculated according to the experimental results. According to the selected contact constitutive parameters, the direct shear test model of PFC-2D and the rock collision springback model are established, and the mesoscopic parameters are calibrated according to the indoor test results and the calculated rock impact springback coefficient. Then the particle flow model of debris flow is established in PFC-2D, and the two-dimensional shape of debris flow ramp is introduced into PFC-2D by Excel. Using HIST command to record and detect the change trend of rock velocity and position, using LOGFILE command to record the position and velocity of all particles at a certain time, and the method of data processing is given. First of all, according to the morphological changes of debris flow, the debris flow can be divided into a large array flow and a number of smaller array flows. The overall change of debris flow is the most intense when the front end of the debris flow just enters the accumulation area, and then the motion gradually attenuates. It is found that the solid source of debris flow tends to stably accumulate at an angle when the debris flow tends to stop. Then the method based on monitoring stone and Largrange method are analyzed, and the results are basically consistent. When the energy of the front end of debris flow into the accumulation area decreases, the other part of debris flow will also be affected. According to the distribution of Savage number and temperature of debris flow, the internal flow state of debris flow is more complex, the transition is very sudden, most of them are in two extreme states of fast flow and slow flow. The debris flow in the middle of the debris flow is relatively stable, the inertial action is dominant, and the collision and energy transfer are very few, and the debris flow in the middle of the debris flow is relatively stable, with frequent particle collisions and large energy transfer. The debris flow in the tail is in a fierce state, similar to the front end, the collision is dominant, but the debris flow in the accumulation area is stable, and the inertial action is dominant.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.23
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