危岩破坏激振信号局部和细节信息特征

Local and minutiae characteristics of excitation signals during perilous rock rupture

危岩属于一种突发性地质灾害，危岩破坏会突然释放能量，以激振波的形式向邻近危岩块传递，劣化相邻危岩体的稳定性。通过坠落式危岩破坏激振效应模型试验，对采集的激振信号进行小波滤噪处理，选取模型试验第25～35 ms共10 ms时间段的激振信号，作为分析激振信号局部和细节信息特征的基础数据。分析结果表明，实验条件下分析时段内，危岩破坏激振信号局部信息存在周期性，激振信号在水平方向存在8～9个激振峰，周期1．0～1．4 ms，在竖直方向存在3～4个激振峰，周期2．2～3．0 ms；测点与激振源之间的距离影响着激振信号的峰值强度，距离越近，峰值强度越大；危岩块之间界面的完整性对激振信号出现频率和峰值强度都有显著影响，激振信号穿过不完整的界面后激振信号主峰存在一定滞后性，实验条件下滞后时间10 ms左右；危岩破坏激振信号的局部和细节信息基本都在细节系数中予以体现，尤其是主频率主要位于d3～d7所对应的中频细节信息内。研究成果对于进一步实施危岩破坏激振效应的相似模型试验具有积极意义。

As one of emergency geological disasters,perilous rock releases abruptly energy during rupture.The energy passes through perilous rock blocks near the rupture position in the form of excitation wave,and it decreases the stability of perilous rocks near the rupture position.Here,by de-noising processing with the wavelet method of excitation signals gathered in a model test of falling perilous rock rupture in laboratory,the signals during 1 0 ms duration from the 25 ms to 35 ms in the model test were taken as the essential data to analyze local and minutiae characteristics of excitation signals during perilous rock rupture.Under the test conditions,analysis results showed that local characteristics of excitation signals during perilous rock rupture have a certain periodicity,i.e.,8 or 9 excitation peaks with 1 .0~1 .4 ms periods exist in horizontal direction,while 3 or 4 excitation peaks with 2.2~3.0 ms periods in vertical direction;the distance between the measuring point and the rupture position significantly affects the amplitude of excitation peaks,the closer the distance, the bigger the amplitude;furthermore,the integrity of the interface between two perilous rock blocks has a significant impact on the frequency and amplitude of excitation peaks,when an excitation signal passes through an incomplete interface,the peaks of the excitation signal are lagged a little,the time-delay is about 1 0 ms under the tests;specially,almost all local and minutiae characteristics of excitation signals during perilous rock rupture can be embodied with minutiae coefficients, the main frequency of excitation signals appear in minutiae characteristics from d3 to d7 .Achievements gained here were helpful for implementation of similar model tests of excitation effect during perilous rock rupture.