审稿意见：
Identification and early warning method of key disaster-causing factors of AE signals for rockburst based on principal component analysis method

作者从城市地质环境的量化评价出发，创造性地提出城市地质环境健康度的概念，构建出了城市地质环境健康度的理论体系，明确了其内涵与外延。通过分析城市地质环境健康度影响因素，采用层次分析法结合专家意见建立了相应的评价体系，并给出了该评价体系的使用方法，实现了城市地质环境的量化评价，全文内容丰富、结构合理，目标和结论明确，具有一定的科学意义，研究结果可以为城市的可持续发展规划提供辅助分析手段，但仍有几点意见：

The failure process of rock materials is usually accompanied by the release of numerous acoustic emission (AE) signals. For accurately evaluating the damage stateof rocks, it is very important to select the effective key disaster-causing signals from themassive AE monitoring data. Based on the uniaxial compression test of red sandstone,the failure precursory characteristics of AE signals were analyzed. Then, based on theprincipal component analysis method, the evolution pattern of key disaster-causingfactors of AE signals were obtained for rockburst, and the early warning method ofbrittle rockburst was also addressed. The results demonstrated that AE parametersignals (AE energy and AE ring counts) and AE waveform signals (AE main frequency)contributed to characterize the precursor of rock failure and fracture. The values of AEenergy and AE ring counts increased significantly in the critical failure stage ofspecimens, and there existed a short quiet period phenomenon of AE signals for rockfailure. Similarly, the signals of AE main frequency increased densely in the criticalfailure stage. Moreover, the optimized key disaster-causing signals (AE energy, AEring counts and AE main frequency) can clearly characterize the stress fluctuation anddamage state of rocks. Based on the optimized key disaster-causing AE signals, theprimary early warning point and the key early warning point of brittle rockbursts wasproposed and determinated, and then a more accurate early warning method ofrockburst was also established. It is hoped that this early warning method can bringsome useful guidance to the risk assessment and stability control in undergroundengineering.

The title of the article is not enough to summarize the content of the full text, and the description based on the principal component analysis is a bit general. This article is mainly based on the frequency analysis method, and the article also mostly analyzes the amplitude and frequency of the waveform signal, which is one of the innovations of the article, and it is suggested to be characterized in the title.

The x axis label of FIG7 exists in Chinese.

Fig 9
“As shown in Fig. 9, the optimized AE energy and AE ring counts has a good correspondence with each other.”

The article’s description of Figure 9 is not consistent with the content of Figure 9. This figure is messy. It is suggested that the author change the transparency of marker to make the meaning of the figure clearer.

fig 10中主预警点和早期预警点的表述存在问题？

For specimen D1, the primary warning point of rockburst corresponded to the yield inflection point of stress curve, and the time of the primary warning point was 678.4s. The critical early warning point of rockburst corresponded to the first stress drop point of stress curve, and the time of the key early warning point was 723.2s. The