摘要
矿山开采沉陷是具有各种裂隙的岩体在采动应力作用下所发生的再变形和再破坏过程,裂隙随着开采的推进不断扩展。如果把矿山岩体原始裂隙看作是初始损伤,则可将随井工开采推进形成的裂隙扩展看作是损伤的演化。根据几何损伤理论中的裂隙张量和FLAC3D莫尔–库仑模型的塑性流动格式建立考虑初始损伤的节理岩体弹塑性本构模型的数值格式,在VC++开发环境中编写这种本构模型,供FLAC3D调用。通过一个单轴压缩数值试验对比,验证该模型应用于节理岩体的合理性。结合采矿工程实际,考虑初始损伤的演化,建立节理岩体采动损伤本构模型,对安家岭露天矿南端帮边坡下的井工开采进行数值模拟,得出露天煤矿台阶状边坡地表不同于平地地表的移动变形规律:台阶处的地表移动范围比平地处大;各级台阶处的变形比较集中。井工开采对上覆边坡岩体造成较大的扰动,不利于边坡的稳定:坡体地表出现安全度小于1的区域,坡体台阶受拉处安全度最小。模拟结果可为露井联采条件下井工开采设计和维护边坡稳定提供合理建议。
Mining subsidence of mines is a procedure of re-distortion and re-damage of rock mass with all kinds of cracks under the influence of mining stress; and these cracks enlarge and develop with the mining proceeds. If the original cracks in rock mass are regarded as primary damage, the enlargement and development of the cracks may be regarded as damage evolvement. Based on crack tensor in geometrical damage theory and plastic flow format of Mohr-Coulomb constitutive model in FLAC^3D, a set of numerical equations of elastoplastic constitutive model of jointed rock mass with primary damage are set up, This model is developed in VC＋＋ programming environment for FLAC^3D to call it. It is compared with Mohr-Coulomb model provided by FLAC^3D and validated for jointed rock mass by a uniaxial compression numerical test, Evolvement of primary damage considered for dynamic characteristic of mining engineering, a constitutive model of jointed rock mass damage due to mining is set up. This numerical model is applied to simulate underground mining under south slope of Anjialing open pit and to research surface subsidence rules and stability of the slope influenced by underground mining. Simulation results are shown as follows： movement range and distortion degree of bench surtace are larger man those of flat surface; underground mining is unfavourable to slope stability for disturbing overlying slope rock mass; and the factors of safety in some slope regions are less than 1 and reach minimal values in tensile benches. Simulation results may bring forward reasonable suggestions for underground mining design and slope stability.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2008年第3期572-579,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家重点基础研究发展规划(973)项目(2005CB221503)
关键词
采矿工程
开采沉陷
节理岩体
本构模型
采动损伤
FLAC^3D
露井联采
mining engineering
mining subsidence
jointed rock mass
constitutive model
damage due to mining
FLAC^3D
open-underground combined mining
