含断续节理岩体地基承载力各向异性的研究.docVIP

 含断续节理岩体地基承载力各向异性的 研究# 师林1,2，朱大勇1,2** 5 10 15 20 25 30 35 40 （1. 合肥工业大学土木与水利工程学院，合肥 230009； 2. 安徽土木工程结构与材料省级实验室，合肥 230009） 摘要：根据含断续节理岩体结构的力学效应和压剪断裂破坏特征，推导了 Hoek-Brown 准则 中参数 m，s 的表达式，并在临界滑动场理论的基础上建立计算含断续节理岩体极限承载力 的新方法，定量地反映节理排列方式及其力学性质等因素对岩体地基承载力各向异性的影响. 计算结果表明：岩体地基承载力的各向异性表现为参数 m，s 的各向异性；此外，岩体地基 承载力不仅与节理产状有关，而且还是围压的函数。 关键词：断续节理；各向异性；断裂力学；地基承载力；Hoek-Brown 强度准则；临界滑动 场 Study on the anisotropy of ultimate bearing capacity of joined rock masses containing intermittent joints SHI Lin1,2, ZHU Dayong1,2 (1. School of Civil Engineering, Hefei University of Technology, HeFei 230009; 2. Anhui Provincial Laboratory of Structure and Materials of Civil Engineering, HeFei 230009) Abstract: The formulas of the parameters m，s in Hoek-Brown criterion can be obtained based on the characteristics of the mechanical effect and compressive-shear fracture behaviour of rockmass containing intermittent joints, and then, the formula of ultimate bearing capacity of rock mass containing intermittent joints is presented combined with the critical sliding field theory. The effect on strength of orientation, length and arrangement of joints is discussed quantitatively which demonstrats the strength anisotropy of this kind of rock mass. The results illustrate that the anisotropism of ultimate bearing capacity is shown by the parameters m，s ；what is more,it has been proved that the anisotropism of ultimate bearing capacity is not only relevant to the orientation of joints,but also a function of confining pressure. Keywords: intermittent joints; anisotropy; fracture mechanics; the ultimate bearing capacity; Hoek-Brown failure criterion; Critical slip fields 0 引言 近年来，越来越多的能源、交通和国防工程建造在岩体中，常常面临节理岩体地基承载 力问题。现有的岩质地基承载力计算理论大多是以 Hoek-Brown 强度准则和 Mohr-Coulomb 强度准则为基础建立的，上述强度理论均是建立在岩石强度各向同性基础之上的，但由于成 岩过程中形成的层面、裂隙和层理等缺陷的存在使岩体具有明显的各向异性，尤其是含断续 节理的岩体，岩桥和节理以不同的阻抗原理共同承担荷载，其破坏机制及强度规律更加复杂。 含断续节理岩体的各向异性问题一直受到国内外有关学者的重视，近年来众多学者将损 伤力学、断裂力学和均匀化理论等方法引入节理岩体各向异性的研究中并得到了一些有意义 的结论，如范景伟等[1-3]以石膏模型试验为基础推导了含节理岩体的强度公式；刘东燕