Piston-Type Blasting Structure for Hard Rock Cable Pit
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Solution Overview
Problem
Conventional mechanical excavation methods for hard rock cable pits are slow and costly, and existing blasting methods often result in 'barrel pulling,' low blasthole utilization, and safety hazards due to uncontrolled flying rocks.
Innovation Solution
A piston-type explosive loading and blasting structure that includes a first-step cut and second-step cuts with a specific arrangement of covers and threaded sections, using powdery explosives and stemming for controlled energy distribution, and a blasting sequence that maximizes energy absorption and rock breaking without throwing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a loose blasting method is used to evenly loosen rocks in a pit, then the blasting coverage is improved, but barrel pulling occurs and flying rocks cause safety hazards
Solution Approach 1:
The blasthole is segmented into multiple zones with different explosive loading quantities. The lower part uses larger explosive quantities to break hard rock and prevent barrel pulling, while the upper part uses smaller quantities to control flying rocks. This segmentation resolves the contradiction by allowing differential treatment of different rock zones within the same blasthole.
Solution Approach 2:
Different explosive loading densities and quantities are applied to different local zones within the blasthole. The lower zone has higher explosive density to address hard rock barrel pulling, while the upper zone has lower density to minimize flying rocks. This local quality variation enables simultaneous achievement of blasting coverage and safety.
2Ease of manufacture
If a uniform explosive loading quantity is used in each blasthole, then the loading process is simplified, but barrel pulling occurs in hard rock strata with low blasthole utilization rate
Solution Approach 1:
The blasthole loading process is segmented into multiple stages with different loading quantities. The lower part receives larger explosive quantities to ensure complete rock breaking and prevent barrel pulling, while the upper part receives smaller quantities. This segmentation improves blasthole utilization rate while maintaining manageable loading complexity through standardized loading procedures.
Solution Approach 2:
The explosive loading quantities are pre-calculated and predetermined for different zones of the blasthole based on rock hardness characteristics. This preliminary action allows the loading process to follow a standardized procedure that improves utilization rate without significantly increasing operational complexity.
3Object-affected harmful factors
If mechanical excavation method is used for hard rock cable pit, then construction safety is improved, but excavation speed is slow and cost is high
Solution Approach 1:
The blasting method applies local quality control through differentiated explosive loading in various zones of the blasthole. This enables safe blasting by controlling fly rock generation while maintaining high excavation efficiency, thus resolving the contradiction between safety and productivity that plagues both mechanical excavation and conventional uniform blasting methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a 100% blasthole-mark rate, improves energy utilization, and ensures safety by fully breaking rock mass and creating a smooth blasting layer, significantly reducing construction time and cost compared to mechanical excavation and traditional blasting methods.
Implementation Method 1
powdery explosives and a detonator are loaded into the blasthole
Implementation Method 2
energy such as stress waves and explosive gas generated after the explosives explode
Implementation Method 3
stemming is loaded into the blasthole according to requirements of blasting design, a top cover sleeves the fixing shaft from a top end of the fixing shaft and covers the stemming
Data Source
AI summary
Provided is a piston-type explosive loading and blasting structure for a hard rock cable pit. The structure includes a first-step cut provided at a center of an excavation section and second-step cuts provided on a periphery of the first-step cut; and piston-type explosive loading structures are used for explosives in the first-step cut and the second-step cuts. According to the piston-type explosive loading structures in the present disclosure, due to plastic plugging of stemming and fixed elastic plugging of two disc steel plates, time of energy such as stress waves and explosive gas generated after the explosives explode acting on surrounding rocks is obviously prolonged, rock mass is fully broken, and loose blasting is formed without throwing.