| Autor: |
Ling, Tianlong, Li, Shenglin, Liu, Dianshu, Liang, Shufeng |
| Předmět: |
|
| Zdroj: |
Rock Mechanics & Rock Engineering; Mar2023, Vol. 56 Issue 3, p1679-1695, 17p |
| Abstrakt: |
Excavation-damaged zones (EDZs) are caused by repeated blasting and can significantly influence the overall performance of underground excavation engineering. The determination of the extent of blast-induced damage is, therefore, a significant concern for engineers in terms of safety and costs. A comprehensive study was conducted to assess the effects of repeated blasting on the accumulative damage of interlaid rock to better understand the characteristics of EDZs that develop during the excavation of small clearance tunnels in underground railway stations. The results of ultrasonic tests show that rock mass wave velocities are influenced by blasting to a depth of approximately 1.6 m. The first blast causes near-field damage and affects the range of the fractured zone, and the subsequent blasts cause far-field damage of the exposed tunnel that subsequently accumulates. Field tests indicate that the influence of repeated blasting should be taken into consideration to properly assess blast-induced damage in tunnels. The damage accumulation process caused by millisecond delay blasting is simulated using commercial software LS-DYNA. The effect of the initial damage on the rock mass mechanical properties in interlaid rock is also considered in the analyses. The simulation results provide instructive insight on the rock damage mechanism and evolution law of accumulative damage caused by drilling and blasting. Highlights: A series of case studies were conducted in a tunnel to investigate the rock mass damage induced by near-field stress waves and far-field blasting vibrations. Characteristics of rock mass damage induced by tunnel millisecond-delay controlled blasting were numerically simulated. The influence of repeated blast loading on cumulative damage was discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Full text from SpringerLink