关键词: 深挖路堑, 危石防护, 浅孔爆破, 中孔爆破

Abstract:

The designed cutting depth of a road channel in NingguoJixi section on YangzhouJixi Expressway reaches 34.5 m. The program of “protection before cutting” is adopted for the deep cutting, so as to minimize the influence of rockfalling and blasting on the operation of the adjacent existing railway. For the dangerous rocks on the surface of the mountain, multiple protection system consisting of active flexible protection measures, passive protection net and rigid retaining wall is established; For the unstable strata in the shallow depth of the road channel, mechanical percussive hammers and static fragmentation method are used; For the rock mass in the deep position of the road bed, sectionbysection and layerbylayer cutting based on shallowhole blasting and mediumhole step controlled blasting is carried out. In the end, the blasting vibration velocity of the retaining wall has been controlled at less than 1.5 cm/s, the displacement of the mountain body has been brought under effective control and the safety of the operating railway has been ensured. 

Key words: deepcut road channel, falling rock protection, shallowhole blasting, mediumdeep hole blasting