摘要
厄瓜多尔某原矿粗碎站基坑设计尺寸为26. 0 m×20. 0 m×43. 9 m,过基坑南边线中间设计有与基坑标高一致宽度为7 m的出渣道路,为减少工程量、加快进度,设计采用3级平台垂直分4层直壁石方爆破开挖基坑和出渣道路。施工中采用深孔预裂与深孔爆破相结合,先爆破出渣道路并深入基坑一部分为后续基坑爆破提供自由面。预裂爆破台阶高度取11~13 m,针对不同围岩预裂孔间距分别取0. 7 m和1. 0m,采用逐孔起爆,微差起爆时间控制在50 ms内。深孔爆破台阶高度10~12 m,炮孔间距和排距均为3 m,采用耦合连续装药和逐孔起爆。施工时加强基坑围岩的振动和位移监测以确保施工安全。
The crushing station design size of a mine in Ecuador is 26. 0 m 20. 0 m 43. 9 m,on the south side of the foundation pit,and a slag discharge road with 7 m wide is consistent with the height of the foundation pit. In order to reduce the amount of work and to speed up the progress,a rock blasting with 4 layers and 3-level vertical platform is adopted. Combination of deep hole pre-cracking and deep hole blasting are adopted in construction. The slag discharge road is excavated deep into the foundation pit to provide free surface for subsequent foundation blasting. The height of pre-split blasting bench is 11 ~ 13 m,for different surrounding rocks,the pre-cracking hole spacing is 0. 7 m and 1. 0 m respectively,hole by hole detonation technology is used and the micro-differential detonation time is controlled within 50 ms. The bench height is 10 ~ 12 m,and the hole spacing and row spacing are 3 m. The coupling continuous charge structure and hole by hole detonation technology are applied. The vibration and displacement monitoring of surrounding rock ensure construction safety well.
引文
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