关键词: 爆破振动, 地下工程, 锚杆支护, 动力响应

Abstract: Aim of this study is to investigate the influence of blasting excavation construction on roadway support bolt. Based on the theory of structural dynamics, the vibration law of bolt under blasting seismic waves is deduced theoretically, including the variation of displacement, vibration speed and axial force on bolt with time. The result shows that the velocity and axial force of the bolt in the free section decrease exponentially, while the axial force, the axial velocity and the shear stress of the bolt in the anchorage section change sinusoidally, and the overall performance increases first and then decreases. The anchorage length has a great influence on the vibration effect of the bolt. The stress state of the bolt varies with the anchorage length of the bolt. On the premise that the tensile strength of the bolt is satisfied, the length of the anchorage section can be reduced appropriately. Shear stiffness has a certain effect on the vibration of the bolt. The greater shear stiffness lead to the greater shear stress between bolt rod and anchoring mortar. Therefore, in order to prevent the bolt from shear failure, the anchorage material with smaller shear stiffness should be chosen as far as possible. The research results have some guiding significance for improving the safety technology in excavating blasting.

Key words: blasting vibration, underground engineering, rock bolt, dynamic response