为研究循环爆破作用下隧道围岩的累积损伤特征，依托山岭隧道工程，提出一种基于声学全波形信号的隧道围岩爆破累积损伤定量表征方法。首先，基于爆破前后的声学全波形信号，推导考虑累积效应的爆破损伤增量公式； 然后，通过引入洛伦兹曲线、基尼系数、分形理论，分析围岩爆破损伤的多维度分布特征； 最后，结合工程岩体爆破前后声学全波形信号主频率和振幅的变化规律，得到其在时域、频域内的变化规律，并利用小波包能量谱进行确认。研究结果表明： 1）声波速度主要反映岩体的平均力学性质； 基尼系数主要揭示损伤的空间分布特征，对振幅的局部剧烈衰减敏感。2）对于完整的围岩岩体，声学全波形信号分布简单，对应的分形维数较低；对于存在裂缝或损伤的工程岩体，由于裂缝的形成和扩展，对应的分形维数相应增加。3）分形维数与浅埋岩体损伤程度呈显著的正相关，但在深部岩体中相关性下降。4）随着爆破次数的增加，爆破累积损伤加剧，但损伤增量逐渐减小，相应信号时域特性表现为声波振幅降低，频域特征表现为主频率和能量向低频方向移动、主频率振幅逐渐减小。
The authors propose a quantitative characterization method based on full acoustic waveform signals to detect cumulative damage in the surrounding rock of mountain tunnels after cyclic blasting. The results provide a theoretical basis for the accurate evaluation of damage to surrounding rock and the precise control of blasting construction. First, a damage-increment formulation that incorporates cumulative blasting effects is derived based on full acoustic waveform signals obtained before and after blasting. Furthermore, the multidimensional spatial distribution of blasting-induced damage in the surrounding rock is characterized by the Lorenz curve, Gini coefficient, and fractal theory. Finally, by examining the variations in the dominant frequency and the amplitude of the full acoustic waveform signals of the engineering rock mass before and after blasting, the evolution patterns in both the time and frequency domains are identified and are further verified using wavelet-packet energy spectra. The results lead to the following conclusions: (1) The acoustic wave velocity primarily reflects the average mechanical properties of the rock mass, whereas the Gini coefficient mainly captures the spatial distribution characteristics of damage and is particularly sensitive to localized abrupt attenuation in amplitude. (2) For intact surrounding rocks, the full acoustic waveform signals exhibit simple patterns, corresponding to relatively low fractal dimensions. In contrast, for cracked or damaged rock masses, the formation and propagation of defects lead to an increase in the associated fractal dimension. (3) The fractal dimension correlates positively with the damage level of surrounding rock in shallow-buried tunnels, whereas this correlation weakens in deep rock masses. (4) The cumulative damage intensifies with the number of blasting cycles, whereas the incremental damage gradually decreases. Thus, the amplitude of the time-domain characteristics of the acoustic signals decreases, the dominant frequency decreases in amplitude, and the lower frequencies gain in amplitude.
