基于PFC2D的黄土轴向压裂试验细观参数敏感性分析  

Sensitivity analysis of meso-parameters of loess in axial fracturing test based on PFC2D

作　　者：贾乐琪 严松宏[1,2] 孙纬宇 欧尔峰 张建[1] JIA Leqi;YAN Songhong;SUN Weiyu;OU Erfeng;ZHANG Jian(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Road&Bridge and Underground Engineering of Gansu Province,Lanzhou 730070,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]甘肃省道路桥梁与地下工程重点实验室,甘肃兰州730070

出　　处：《水资源与水工程学报》2023年第2期194-201,共8页Journal of Water Resources and Water Engineering

基　　金：国家自然科学基金项目(52208392、52168058);甘肃省自然科学基金项目(21JR7RA309);甘肃省道路桥梁与地下工程重点实验室开放基金课题(GSDQ-KF2020-5);中国博士后科学基金项目(2021M693843)。

摘　　要：黄土的低抗拉能力是黄土地区工程建设中病害频发的重要原因。采用离散元程序PFC2D对黄土轴向压裂试验进行数值模拟,通过控制变量法改变单个细观参数取值,分析其对黄土抗拉特性的影响,并结合正交试验,对各细观参数进行了敏感性分析。结果表明:黄土的抗拉强度与黏结刚度比k_(n)/k_(s)呈对数递减关系,与黏结强度σ_(c)、半径乘子λ呈线性递增关系;黄土的抗拉刚度与黏结刚度比呈对数递减关系,与半径乘子呈线性递增关系;半径乘子对抗拉强度的影响最强,黏结刚度比对抗拉刚度的影响最强,粒径比r^(*)对抗拉强度、抗拉刚度的影响均最弱。研究可为黄土轴向压裂试验数值模拟中细观参数的标定提供参考。The low tensile strength of loess is one of the important causes of the frequent occurrence of hazards in the engineering construction in loess area.Regarding to this problem,the numerical simulation of loess axial fracturing test is carried out using the discrete element program PFC2D,with which the influence of single meso-parameters on the tensile properties of loess is studied by variable-control method,and the sensitivity of each meso-parameter is analyzed by orthogonal test.The results show that the tensile strength of loess decreases logarithmically with the k_(n)/k_(s) ratio of bonding stiffness,and increases linearly with the bonding strength σ_(c) and radius multiplier λ.Moreover,The tensile stiffness of loess decreases logarithmically with the kn/ks ratio,and increases linearly with the λ.Furthermore,the radius multiplier has the strongest influence on the tensile strength,the bonding stiffness ratio has the strongest influence on the tensile stiffness,and the particle size ratio r^(*) has the weakest influence on the tensile strength and the tensile stiffness.The study can provide some reference for the selection of meso-parameters in the numerical simulation of loess axial fracturing tests.

关 键 词：黄土轴向压裂 数值模拟 抗拉强度 细观参数 敏感性分析 PFC2D 

分 类 号：TV16[水利工程]