Application Research On Construction Technique In Permafrost Blasting

Blasting and excavation in permafrost, in particular those with a depth of dozens of meters or even hundreds of meters, is always a major problem to be solved in the field of both rock and soil engineering and blasting engineering. The difficulty is that the physical and mechanical properties of permafrost are different greatly from each other and the operability of drilling and blasting vary with the permafrost property and the explosion capability of the used explosives. Anti-freezing of explosives is also a major concern. Therefore, when performing drilling and blasting in permafrost, proper blasting materials and drilling equipment should be selected, and appropriate blasting method and parameters should be determined, and all these should be based on specific engineering geological conditions and environmental conditions. Tackling the foresaid problems may help to raise the level of permafrost blasting technology, and to enrich and promote blasting theories.The thesis focuses on experiment and research about blasting technology for permafrost, which was based mainly on Qinghai-Tibet Railway, in particular the different physical and mechanical properties of permafrost at different locations along the railway alignment. The research also borrowed relevant fruits both at home and abroad. Tests were made to compare drilling efficiency of different drillers, and principles were determined to choose proper drilling machine according to specific permafrost nature. Site experiments were conducted to investigate the water-resistant and anti-freezing performance of blasting equipment and materials, and the adaptability to harsh environmental conditions, for example, under very low temperature. Principles were therefore developed for using suitable equipment and materials according to ambient temperature.Tests result and analysis shows that, blasting for loosening soil is suitable for the permafrost over the plateau, and three methods, namely shallow hole blasting, deep hole blasting, and pot hole blasting, should be preferably used, while chamber blasting is inadvisable. Shallow hole blasting is suitable for the site with complicated terrain and excavation depth less than 2 meters. Deep hole blasting is suitable for the...