To study the movement law of rock blocks inside the wedge cut cavity in tunnel blasting and to determine the reasonable delay time for wedge cutting,a theoretical model of the rock block throwing process in wedge cut blasting was established based on reasonable assumptions.The time-history curves of rock block movement inside the wedge cut cavity under different design parameters were solved using the one-dimensional unsteady flow law and Newton's second law.The SPH-FEM coupled numerical simulation was used to verify the rationality of the de-rived movement law of rock blocks inside the cavity and the throwing process of the rock blocks to be blasted under different hole network parameters,as well as the throwing characteristics and movement law of rock blocks in the cavity.The results indicate that when the first wedge cut depth is 2.0 meters,the reasonable delay time for the second wedge cut hole in soft rocks,medium-hard rocks,and hard rocks is 32.68-35.66 ms,33.10-36.45 ms,and 34.4-38.22 ms,respectively.The designed delay time for the"two-step"wedge cutting needs to be greater than the above-mentioned cavity formation time.
关键词
隧道爆破/楔形掏槽力学模型/牛顿第二定律/SPH-FEM/抛掷运动/延期时间
Key words
Tunnel blasting/Mechanical model of wedge cutting/Newton's second law/SPH-FEM/Throwing mo-tion/Delay time
维普
万方数据