摘要
厚煤层综采放顶煤开采的沿空巷道顶、帮均为煤体或煤柱,其稳定性问题十分突出。以南屯煤矿综放沿空巷道为原型,进行围岩稳定性的离散元数值模拟,提取表征系统动力学性态的变量及时间序列,通过功率谱分析、分维数提取和最大Lyapunov指数计算,研究围岩系统的混沌动力学特征。综放沿空巷道围岩变形力学过程是一个混沌力学过程,具有对煤柱宽度及支护条件等初始条件的敏感依赖性。当煤柱宽度小于3 m时,功率谱具有连续的噪声背景与宽峰特征,关联维数均为分数,最大Lyapunov指数一般大于0,系统处于混沌运动状态;当煤柱宽度为3～4 m时,锚杆支护后功率谱的宽峰特征消失,频谱成分也不丰富,关联维数均为分数,最大Lyapunov指数由正变负,系统由混沌运动向定常运动转变,是系统动力学性态变化的拐点;当煤柱宽度大于5 m时,系统处于定常运动状态。采用功率谱分析法和最大Lyapunov指数法,可以评价综放沿空巷道的混沌动力学特征。
The roof and side of fully-mechanized caving roadway are coal body or coal pillar which cause the stability problem extremely prominent. The fully-mechanized caving roadway of Nantun Colliery is set as the prototype, its surrounding rock stability problem is analyzed by numerical simulation with distinct element method and the variable and time series that describe system dynamic state are collected. The chaos and dynamic feature of the surrounding rock system are studied based on the power spectrum analysis, extraction of fractal dimension and calculation of maximum Lyapunov exponent. The deformation mechanic process of fully-mechanized caving surrounding rock is chaos dynamic process which is sensitive to initial factors; the pillar width and support condition have great effect on surrounding rock displacement, stress and damage area. The power spectrum has the feature of continuation, noise background and wide peak, the correlation dimension value is fraction and maximum Lyapunov exponent is generally greater than zero when the pillar width less than 3 m; the system would be in a chaos motion state at present. When the pillar width is 3 - 4 m and after bolt support, the wide peak feature of power spectrum vanished and the frequency spectrum is not profuse; the correlation dimension value is fraction but maximum Lyapunov exponent changes from positive to negative; system state changes from chaos motion to normal motion; this status is an inflection point of system dynamic state transformation. When the pillar width larger than 5 m, system will be in normal motion state. The reasonable pillar width is 3 - 5 m. The chaos dynamic feature of fully-mechanized caving roadway can be evaluated according to the application of power spectrum analysis and maximum Lyapunov exponent method.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2006年第9期1755-1764,共10页
Chinese Journal of Rock Mechanics and Engineering
基金
山东省自然科学基金资助项目(Q99F07)
教育部骨干教师计划资助项目
关键词
采矿工程
综放沿空巷道
离散元法
动力学性态
混沌运动
功率谱
LYAPUNOV指数
mining engineering
fully-mechanized caving roadway
distinct element method： dynamic state
chaos motion： power spectrum
Lyapunov exponent
