基于格子Boltzmann方法的粗糙岩体裂隙渗流特性数值模拟研究

发布时间：2018-04-23 18:47

本文选题：格子Boltzmann + 节理裂隙粗糙度系数　；参考：《昆明理工大学》2017年硕士论文

【摘要】：格子玻尔兹曼方法模拟岩体裂隙渗流场,较传统的数值模拟具有天生的并行特性、边界条件处理简洁、程序易于实施、能得到清晰的物理图像等独特优势。通过JRC数值生成法建立起在一定范围内的节理粗糙度系数JRC的二维岩体吻合裂隙结构;通过中点插值法生成了JR 值在一定范围内的三维岩体结构裂隙面。基于格子玻尔兹曼方法(LBM),设置出入口为非平衡态外推格式、上下岩体裂隙表面为标准反弹格式、镜面反弹格式或周期性边界处理法,建立了模拟岩体裂隙渗流模型。通过C++编程实现格子玻尔兹曼方法模拟并验证了经典的泊肃叶流动,计算了不同JRC值粗糙裂隙面下的渗流特性,讨论了节理面粗糙度系数JRC、压力差的大小和裂隙宽度对线性流流态的影响。本文做的主要工作如下:(1)用岩体粗糙单裂隙面的JRC~(2D)数值生成法。该方法只需要在Visual Studio的源程序中运用a,bi,c,,四个参数便就可以生成一定粗糙度的单裂缝,在这四个参数中ci·和名这两个参数可以起到控制相对起伏幅度Ra值的功用;而伸长率R值则由ai,bi,ci,di四个参数值共同决定。只要控制这四个简单的参数就可以生成一个特定JRC值的二维粗糙岩体节理裂隙面。该方法操作方便、操作性极强,具有广阔的发展前景。(2)通过控制变量法,研究一定节理粗糙度系数JRC的岩体裂隙渗流特性与压力差△P和隙宽b之间函数关系。(3)节理裂隙粗糙度系数JRC和立方定理中的指数n值之间成逆相关线性函数关系。当裂隙结构面越粗糙,对流场动能的消耗约严重,所以流量会减少,倒推得到n值也会减少,致使了次立方渗流的诞生。本文利用格子玻尔兹曼方法验证了泊肃叶流;并用格子玻尔兹曼方法研究了二维、三维两种情况下的岩体裂隙渗流,这些研究不但对实际工程应用具有指导意义,而且进一步加深了我们对岩体裂隙渗流的理解和认识。
[Abstract]:The lattice Boltzmann method is superior to the traditional numerical simulation in simulating the seepage field of fractured rock mass, which has the advantages of natural parallelism, simple boundary condition processing, easy implementation of the program, and the ability to obtain clear physical images. Through the JRC numerical generation method, the 2D rock mass coincidence fracture structure with joint roughness coefficient JRC is established in a certain range, and the 3D rock structure fracture plane with Jr value in a certain range is generated by the midpoint interpolation method. Based on the lattice Boltzmann method and the non-equilibrium extrapolation scheme, the seepage model of the rock mass fracture is established by setting the entrance as the non-equilibrium extrapolation scheme, the upper and lower rock cranny surface as the standard rebound scheme, the mirror surface rebound scheme or the periodic boundary treatment method. The lattice Boltzmann method is used to simulate and verify the classical Poisson flow, and the percolation characteristics of rough fracture surfaces with different JRC values are calculated. The effects of roughness coefficient JRC, pressure difference and crack width on the linear flow state are discussed. The main work of this paper is as follows: (1) using the JRCU 2D) numerical method of the rough single fracture plane of rock mass. This method only needs to use a Visual Studio source program, and four parameters can produce a single crack with a certain roughness. In these four parameters, ci and name can control the relative fluctuation amplitude Ra value. The R value of elongation is determined by the four parameter values. Once the four simple parameters are controlled, a two-dimensional joint and fissure plane with a specific JRC value can be generated. This method is easy to operate, highly operational, and has a broad prospect of development. The relationship between the seepage characteristics of rock mass fractures with certain joint roughness coefficient (JRC) and the function relationship between pressure difference P and gap width b) between the roughness coefficient JRC of joints and the exponent n value in cubic theorem is studied. When the fracture surface is rougher, the kinetic energy of the flow field will be consumed seriously, so the flow rate will be reduced, and the n value will be reduced, which will lead to the birth of sub-cubic seepage. In this paper, the lattice Boltzmann method is used to verify the Poisuye flow, and the lattice Boltzmann method is used to study the seepage of rock mass fractures in two and three dimensions. These studies are not only of guiding significance to the practical engineering application, but also of great significance to the application of the lattice Boltzmann method. Moreover, it further deepens our understanding and understanding of rock mass fracture seepage.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU45

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