tailieunhanh - Systematic Drilling and Blasting for Surface Excavations Part 14

Tham khảo tài liệu 'systematic drilling and blasting for surface excavations part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | EM 1110-2-3800 1 Mar 72 APPENDIX B TYPICAL CE BLASTING SPECIFICATIONS 1-1. Introduction. Paragraphs 1-2 1-3 and 1-4 below are examples of typical actual construction specifications on blasting for large structures and roadcuts. Only the portions pertaining to blasting have been extracted. The fourth example par. 1-5 specified seismic monitoring for vibration and damage control at a large quarry. 1-2. Blasting Specifications for Spillway and Intake Structure in Andesite and Tuff Breccia Blue Rivet Dam. SECTION 3. EXCAVATION 3-04. EXCAVATION FEATURES. j. Excavation Intake Structure. - 1 A prism of rock not less than 15 feet wide adjacent to the walls of the intake structure above elevation 1150 shall be drilled and blasted in lifts not exceeding 20 feet in depth only after removal of the interior portion of the channel. 2 A prism of rock not less than 15 feet wide adjacent to the face forming the tunnel portal shall be excavated only after removal of the interior portion of the channel. Above elevation 1160 the blasting lifts shall not exceed 20 feet in depth. Below elevation 1160 the blasting lifts shall not exceed 10 feet in depth. All blast holes in the rock prism adjacent to the portal slope shall be deck loaded or loaded with explosives on a detonating cord and delayed in a pattern and sequence that will prevent back-pres sure and damage to final faces. Presplit blasting shall be used along the portal face down to elevation 1160. Below elevation 1160 Line Drilling shall be used along the portal face and along each end of the rock prism adjacent to the portal slope. Line Holes shall not be more than one hole diameter apart and shall not be loaded with explosives. k. Excavation Spillway Channel. - The 20-foot-wide zone of rock adjacent to each of the two channel walls shall be excavated only after removal of the interior portion of the channel excavation. In addition to presplit blastholes along the final slopes the width of lifts and the pattern and B-l EM .