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3D DEM simulation of hard rock fracture in deep tunnel excavation induced by changes in principal stress magnitude and orientation 被引量:2
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作者 Weiqi Wang Xia-Ting Feng +2 位作者 Qihu Wang Rui Kong Chengxiang Yang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期3870-3884,共15页
To achieve the loading of the stress path of hard rock,the spherical discrete element model(DEM)and the new flexible membrane technology were utilized to realize the transient loading of three principal stresses with ... To achieve the loading of the stress path of hard rock,the spherical discrete element model(DEM)and the new flexible membrane technology were utilized to realize the transient loading of three principal stresses with arbitrary magnitudes and orientations.Furthermore,based on the deep tunnel of China Jinping Underground Laboratory II(CJPL-II),the deformation and fracture evolution characteristics of deep hard rock induced by excavation stress path were analyzed,and the mechanisms of transient loading-unloading and stress rotation-induced fractures were revealed from a mesoscopic perspective.The results indicated that the stressestrain curve exhibits different trends and degrees of sudden changes when subjected to transient changes in principal stress,accompanied by sudden changes in strain rate.Stress rotation induces spatially directional deformation,resulting in fractures of different degrees and orientations,and increasing the degree of deformation anisotropy.The correlation between the degree of induced fracture and the unloading magnitude of minimum principal stress,as well as its initial level is significant and positive.The process of mechanical response during transient unloading exhibits clear nonlinearity and directivity.After transient unloading,both the minimum principal stress and minimum principal strain rate decrease sharply and then tend to stabilize.This occurs from the edge to the interior and from the direction of the minimum principal stress to the direction of the maximum principal stress on theε1-ε3 plane.Transient unloading will induce a tensile stress wave.The ability to induce fractures due to changes in principal stress magnitude,orientation and rotation paths gradually increases.The analysis indicates a positive correlation between the abrupt change amplitude of strain rate and the maximum unloading magnitude,which is determined by the magnitude and rotation of principal stress.A high tensile strain rate is more likely to induce fractures under low minimum principal stress. 展开更多
关键词 Deep hard rock tunnel three-dimensional(3D)discrete element model(DEM) Magnitude and orientation of principal stress Transient unloading Fracture mechanism
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MODELING UNCONFINED SEEPAGE FLOW USING THREE-DIMENSIONAL NUMERICAL MANIFOLD METHOD 被引量:25
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作者 JIANG Qing-hui DENG Shu-shen +1 位作者 ZHOU Chuang-bing LU Wen-bo 《Journal of Hydrodynamics》 SCIE EI CSCD 2010年第4期554-561,共8页
Three-dimensional numerical manifold method for unconfined seepage analysis is proposed in this article.By constructing hydraulic potential functions of the manifold element,the element conductivity matrix and the glo... Three-dimensional numerical manifold method for unconfined seepage analysis is proposed in this article.By constructing hydraulic potential functions of the manifold element,the element conductivity matrix and the global simultaneous equations for unconfined seepage analysis are derived in detail.The algorithm of locating the free surface and the formula for seepage forces are also given.Three-dimensional manifold method employs the tetrahedral mathematical meshes to cover the whole material volume.In the iterative process for locating the free surface,the manifold method can achieve an accurate seepage analysis of the saturated domain below the free surface with mathematical meshes unchanged.Since the shape of manifold elements can be arbitrary,the disadvantage of changing the permeability of transitional elements cut by the free surface in the conventional Finite Element Method(FEM) is removed,and the accuracy of locating the free surface can be ensured.Furthermore,the seepage force acting on the transitional elements can be accurately calculated by the simplex integration.Numerical results for a typical example demonstrate the validity of the proposed method. 展开更多
关键词 three-dimensional seepage numerical manifold method free surface mathematical mesh manifold element
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数值流形方法的对象设计 被引量:4
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作者 张湘伟 蔡永昌 骆少明 《计算力学学报》 CAS CSCD 北大核心 2001年第1期8-14,共7页
研究了数值流形方法的对象设计方法和组织方式 ,为流形方法的理论研究和向三维问题的扩展打下良好的基础。研究发现数值流形方法具有编程和前后处理简单的特点 ,且仅用三角形流形单元和一阶近似的覆盖位移函数就可达到有限元多结点等参... 研究了数值流形方法的对象设计方法和组织方式 ,为流形方法的理论研究和向三维问题的扩展打下良好的基础。研究发现数值流形方法具有编程和前后处理简单的特点 ,且仅用三角形流形单元和一阶近似的覆盖位移函数就可达到有限元多结点等参元的求解精度 ,具有深远的工程意义。计算结果表明 。 展开更多
关键词 数值流形方法 对象设计 有限元法 三维问题 程序设计
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三维数值流形的面向对象设计 被引量:3
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作者 骆少明 张湘伟 姜东茹 《重庆大学学报(自然科学版)》 EI CAS CSCD 北大核心 2003年第12期10-14,共5页
在给出扩展的三维数值流形的理论基础上,将面向对象技术引入到三维数值流形方法的程序设计中,详细地研究了基于三维数值流形理论的面向对象的程序设计和管理方法,并进行了类的设计,还给出了其中一些关键类的原型。作为应用实例,给出了... 在给出扩展的三维数值流形的理论基础上,将面向对象技术引入到三维数值流形方法的程序设计中,详细地研究了基于三维数值流形理论的面向对象的程序设计和管理方法,并进行了类的设计,还给出了其中一些关键类的原型。作为应用实例,给出了三维数值计算结果。数值算例表明该算法与理论结果吻合,从而证明了面向对象程序设计的正确性。 展开更多
关键词 三维数值流形方法 面向对象技术 有限元方法
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三维数值流形法块体切割技术研究 被引量:5
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作者 柯锦福 王水林 《岩土力学》 EI CAS CSCD 北大核心 2020年第10期3473-3480,共8页
运用布尔碎片运算实现了简单的三维块体切割功能,形成覆盖整个求解域的六面体网格,再将六面体单元拆分生成48个四面体单元,从而生成四面体数学覆盖。运用布尔交运算将四面体单元与求解域求交集得到流形块体,再根据三维拓扑有向性原理和... 运用布尔碎片运算实现了简单的三维块体切割功能,形成覆盖整个求解域的六面体网格,再将六面体单元拆分生成48个四面体单元,从而生成四面体数学覆盖。运用布尔交运算将四面体单元与求解域求交集得到流形块体,再根据三维拓扑有向性原理和三维单纯形积分理论,形成了有向边、有向环、有向面和有向壳4种有向几何数据结构,用来构造生成封闭的有向三维流形单元。定义了有向流形单元的连通内面对和连通的有向流形单元的概念,利用有向流形单元的连通内面对搜索生成物理覆盖体系。概括总结了基于修正对称和反对称分解的三维数值流形元法的求解计算要点,在不考虑三维接触、三维裂纹尖端奇异场和三维裂纹扩展的假设下,模拟了三维节理面的有限塑性变形张拉过程,得到了比较合理的数值模拟结果,验证了前处理和计算求解算法的正确性。 展开更多
关键词 三维数值流形元法 有向三维流形单元 连通内面对 物理覆盖搜索 修正对称和反对称分解
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