Control of Rock Block Fragmentation Based on the Optimization of Shaft Blasting Parameters
Table 3
Geological conditions of the shaft in Jinhua mountain tunnel.
Elevation
Geological conditions
Surrounding rock classification
476.0-467.5
It is a silty clay with gravel, which is loose with block stones distributed locally.
V
467.5-456.0
It is tuff of Huangjian formation or crystal chip fusion, the rock is strongly weathered and locally contains breccia, rock joints and cracks are developed, and the rock quality is hard.
IV
456.0-222.5
It is tuff and crystal debris fusion tuff, which are moderately weathered. The joints and crack are generally developed, thereby showing the block structure mosaic fragmentation. It belongs to hard rock with good integrity. It is locally mixed with tuff silty sandstone, and the rock quality is relatively hard.
