Microseismicity evolution related to two extremely intense rockbursts in a water diversion tunnel. (April 2023)

• Record Type: Journal Article
• Authors: Wang, Yucheng; Tang, Chun'an; Cai, Ming; Tang, Liexian; Ma, Tianhui; Zhang, Shichao; Li, Limin; Li, Yubo
• Is Part Of: International journal of rock mechanics and mining sciences. Volume 164(2023)
• Publication Date: 2023-04
• Subjects: Hanjiang-to-weihe river diversion project -- Extremely intense rockburst -- MS monitoring -- Structural plane -- Microseismicity characteristics; Rock mechanics -- Periodicals; Soil mechanics -- Periodicals; Mining engineering -- Periodicals; Roches, Mécanique des -- Périodiques; Sols, Mécanique des -- Périodiques; Technique minière -- Périodiques; 624.151305
• DOI: 10.1016/j.ijrmms.2023.105359
• Languages: English
• ISSNs: 1365-1609

Abstract

Abstract: During the construction of the Qinling diversion tunnel of the Hanjiang-to-Weihe River Diversion Project, intense rockbursts and extremely intense rockbursts occurred frequently, threatening the safety of workers. To understand the characteristics and evolutionary process of extremely intense rockbursts, in-situ microseismic (MS) monitoring was carried out in this project. In this paper, two sequential extremely intense rockbursts were investigated by analyzing recorded MS events. The spatial evolution and density contours of MS events illustrated the dynamic progressive characteristics of MS activities as they propagated and accumulated along two intersecting structural planes and finally formed a cluster zone. Frequent occurrence of high-energy MS events, the bimodal distribution of MS events with different energies, an increase in the log energy index ( EI ) to a high level accompanied by rapidly increased cumulative apparent volume and an increase in the proportion of high-energy tensile failure events indicated a relatively high risk of extremely intense rockburst. The failure types of MS events revealed that the rockburst underwent alternating shear failure, mixed failure, and tensile failure. Finally, the dynamic prevention method based on MS monitoring effectively reduces the risk of extremely intense rockbursts. These research results provide an important reference for extremely intense rockburst warning and prevention in this project and other deep tunneling projects.