危岩锚固机理的断裂力学分析-重庆大学学报.PDF

第28卷 第5期 重 庆 建 筑 大 学 学报 Vo1．28 No．5 2006年 l0月 Journal of Chongqing Jianzhu University 0ct．2006 危岩锚固机理的断裂力学分析 陈洪凯， 胡 明， 唐红梅 (重庆交通大学 岩土工程研究所，重庆 400074) 摘要：危岩主控结构面受荷断裂扩展是危岩失稳的根本原因。用锚杆加固危岩体在危岩治理中有着广 泛应用，效果十分明显。从线弹性断裂力学角度考虑锚固力对危岩主控结构面的阻裂增韧作用，分析在 拉剪综合应力作用下锚固力对减小主控裂隙面尖端相当应力强度因子的贡献，并讨论了锚杆水平角变 化对相当应力强度因子的影响。以重庆万州太白岩危岩为例计算结果表明，锚固力的存在使得相当应 力强度因子明显减小，并随着锚杆倾角的增大，其成抛物线变化，并在20。～30。时具有最优锚固效果。 关键词：危岩；锚固效果；断裂模型；相当应力强度因子；锚固角 中图分类号：P642．3；0346．5 文献标识码：A 文章编号：1006—7329(2006)05—0101—05 Fracture Mechanics Analysis of Control Fissure of Bolted Perilous Rock CHEN Hong—kai，HU Ming，TANG Hong—mei (Institute of Geoteehnieal Engineering，Chongqing Jiaotong University，Chongqing 400074，P．R．China) Abstract：Crack propagation of control fissure of perilous rock under loads is the key process in failure of perilous rock． The rock anchoring with its reinforcing effect as one of the measures to control perilous rock is widely applied．In this pa- per，a new model of perilous rock mass reinforced by passive，fully～grouted bolt based on fracture mechanics has been proposed．In this model a special attention is paid to the fracture toughness increment of the control fissure by bolting the perilous rock．Moreover，a fitting bolting angle does well too in preventing the control fissure against crack propagation． A simple and rationally approximate expression of stress intensity factor of falling perilous rock mass is given．Taking the Taibaiyan perilous rocks as an example，the calculating results show that there is an obvious reduction of the stress inten- sity factor er the anchor has taken effect and there is nonlinear relationship between the bolting angle and stress inten． sity factor and 20。～30。bolting angle is recommended． Keywor