Zhang W.,Shandong Jiaotong University |
Zhang W.,Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation SDUST |
Chen S.,Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation SDUST
Applied Mechanics and Materials | Year: 2012
Based on the measured single-stage blasting vibration signal, time-frequency characteristics of two single-stage superposing signals were analyzed under the condition of different millisecond intervals ranging from 1ms to 350ms, also, variation laws of dominant frequency, amplitude and energy of the blasting vibration superposing signal with the delay time and the determination method of rational millisecond interval of similar engineering were put forward. Then, changing laws of the millisecond interval with the interference effect was obtained. It is found that, millisecond delay blasting does not follow the disturbance vibration reduction theory strictly that the vibration effect is weakened when interval is (2n-1)T/2 and strengthened when interval is nT, and the more similar the vibration characteristics of single-stage signals are, the larger the maximum amplitude declining rate of the obtained superposing signal is. © (2012) Trans Tech Publications, Switzerland.
Duan B.,Shandong University of Science and Technology |
Duan B.,Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation SDUST |
Zhu Y.,Shandong University of Science and Technology |
Zhu Y.,Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation SDUST |
And 2 more authors.
Modern Tunnelling Technology | Year: 2013
The Tai'an Station to Yijing Station running tunnel section of the Shenzhen Metro lines 5 and 7 is designed as a shallow-buried tunnel. Considering that there are many surface buildings, and following the requirements of technical standards, blasting vibration should be monitored to ensure construction safety. This paper analyzes the moni-toring data obtained from some typical monitoring sections and determines the vibration law in radial and normal directions. In the radial direction, the vibration velocity in the excavated area is greater than that of the unexcavated area; in the normal direction, the vibration velocity reduces linearly from the working face to two sides with the center at the working face (zero test point). The results show that shock absorption is evident by drilling intensive damping holes and stemming the bottom holes with bamboo, and the shock-absorption effect in the radial direction is better than that in the normal direction.