RESEARCH OF DRILLING AND BLASTING METHOD BASED ON A SUPER-LARGE CROSS-SECTION CAVERN IN HONG KONG

With the increasing demand for urban underground space, the construction of oversized caverns has become an important issue in the field of underground engineering. The traditional drilling and blasting methods face challenges such as difficult design, large charge and large blasting volume when applied to the construction of oversized caverns. In this paper, a large cavern project in Hong Kong is used as an example to systematically study the drilling and blasting method applicable to super-large cross-section caverns. The method adopts large-diameter holes (51mm), micro-differential blasting technology, combined with high-precision rock drilling cart for fully automatic drilling, which significantly improves the blasting efficiency, reduces the rate of duds, and effectively controls the problem of over-under-excavation. By optimizing the arrangement of the holes and the selection of explosives, the average amount of explosives per cubic meter of rock was reduced to 1.2kg, which significantly saves the construction cost. In addition, the method is excellent in safety, environmental protection and flexibility, and the vibration monitoring points are provided at the construction site. So, the vibration generated by blasting has minimal impact on the surrounding environment. The research results of this paper provide an important reference for the construction of similar super-large cross-section caverns by drilling and blasting method, which has a high popularization value.