## 7 Conclusions  
This article systematically summarized the latest research results obtained by rockburst early warning methods proposed in recent years. Combined with the new practice in the early warning approaches, early warning methods based on microseismic indices, and a mechanical model were summarized, and the respective application scenarios of the two methods were explored. Combined with the practical problems encountered in the early warning of rockbursts, the development directions for future research were pointed out. The main conclusions are as follows:  
1. Rockburst is a disaster induced by the progressive destruction under the action of excavation unloading, stress adjustment, external disturbance, and other factors, exhibiting an evident microseismic evolution process and precursory characteristics. With the help of microseismic monitoring technology, the stress change and microfractures in the surrounding rock during excavation can be monitored continuously and in real time. By observing the microseismic evolution characteristics of the rockburst formation process, the precursory laws of rockburst were summarized, and finally, the dynamic early warning of rockbursts was realized on the basis of these precursory laws. 2. Tunnel engineering is an unfavorable environment for microseismic monitoring systems. The P- and S-wave arrival times should be used in positioning. In the selection of the location detection algorithm, the effects of the pickup error and velocity model accuracy on the location results should be considered. 3. The formation process of a rockburst can be divided into three stages: transition period, peak period, and quiet period. Before a rockburst, the dominant frequency of the microtremors tends to decrease. The special type of rockburst has its unique formation process and microseismic evolution law. For structure-type rockbursts, high-energy microseismic events often occur in the early stage of the rockburst process, and shear rupture is the dominant microseismic mechanism in the rockburst formation process. At the initial stage of surrounding rock excavation, the microseismicity of the delayed rockburst is intense, but then gradually decreases. On the eye of a delayedrockburst, the precursory characteristics are not evident. By judging the type of rockburst, the accuracy of early warning can be improved. 4. Because the intensity of a single microseismic event is random, but shows an overall trend, the microseismic index that can reflect this evolution trend has become the focus of early warning research. Different microseismic indices have their own advantages and scope of application. To improve the early warning effect and avoid the misjudgment of a single index, a multi-index comprehensive prediction of rockburst risk and rockburst level is typically applied. Using the DNN and establishing functional relationships from the microseismic indices for the prediction of rockbursts, an intelligent early warning of rockbursts can be realized. 5. By solving the source parameters, judging the stage of rock mass stability according to the two-body interaction theory, determining the rockburst risk and rockburst formation stage, and analyzing the stress adjustment process of the surrounding rock with the 3S theory, the early warning of rockbursts based on a mechanical model can be realized. The development and evolution trend of rockbursts can be predicted. 6. For the rockburst in the excavation unloading stage, the early warning method based on microseismic indices should be used to predict the risk and level of rockbursts, and for rockbursts that may occur after the completion of the support, the early warning method based on the mechanical model should be adopted. The support effect should be evaluated, and the potential rockburst area and risk probability should be predicted. Conceptualization, S.Z. and C.T. ; methodology, S.Z. ; writing--original draft preparation, S.Z. and J.L. ; investigation, S.Z., Y.W. and K.W. ; writing--review and editing, C.T. and T.M. ; supervision, C.T.