摘要
危岩破坏激振效应是危岩聚集体连锁破坏的主要影响因素。针对坠落式危岩，进行室内模型试验，对实验结果分析表明，可以采用相干系数分析法判别危岩破坏激振信号质量的有效性，实验量测到的危岩破坏激振信号均处于a3（0～1250 Hz）频率带内，采用db8（3层）小波处理方法获得了激振信号小波分解系数时程变化曲线，据此通过Fou-rier变换，获得其频谱图；危岩破坏激振信号总体呈现衰减趋势，但衰减过程中分别在900 Hz、1100 Hz和1500 Hz频率处出现三个峰值；测点与激振源之间的距离越小，激振加速度越大，且竖直方向的量值均大于水平方向的量值；危岩块之间界面完整性越好，越利于激振信号的传递，竖直方向衰减率高于水平方向衰减率。研究成果对于科学揭示群发性危岩破坏机制具有积极意义。
Abstract
The excitation effect of perilous rocks is one of main impact factors to induce the chain damage of unstable aggregation rock blocks.Aiming at a falling perilous rock,a laboratory model test for testing its excitation effect was conducted.The test results showed that firstly,the quality effectiveness of the excitation signals can be determined with the coherent coefficient analysis method,and almost all the measured excitation signals of unstable rock are distributed in a3 (0 !1250Hz ) frequency range;secondly,the time-history curve for each wavelet decomposition coefficient of an excitation signal can be gained with the db8 (3 layers)wavelet analysis method,and its spectrum figure can be obtained through Fourier transformation;thirdly,the excitation signal totally presents an attenuation trend,and it has three peak values at 900Hz,1 100Hz and 1500Hz;the larger the distance between a measured point and the fountainhead of an excitation signal,the bigger the excitation acceleration,and the excitation acceleration in the vertical direction is bigger than that in the horizontal direction;fourthly,the better the integrality of interface between two perilous rocks,the easier the transfer of excitation signals,and the decay rate in the vertical direction is higher than that in the horizontaly direction.The results had a positive effect on revealing the damage mechanism of group-occuring unstable rock blocks.
基金项目
国家自然科学基金(11272185)
国家自然科学基金(51378521)
重庆市“两江学者”计划专项经费资助()
2013年重庆高校创新团队建设计划资助项目(KJTD201305)
NETL
NSTL
维普
万方数据