摘要
Abstract
How to build a new tunnel crossing below an existing tunnel in the form of small clear distance and large angle is always one of the difficult problems in tunnel design and construction, because the construction process not only should ensure the safety of the newly-built tunnel, but also should ensure a safe and normal operation of the existing tunnel. Based on an actual project of a newly-built mountain-area tunnel crossing below an existing railway tunnel, this paper theoretically calculated the minimum clear distance between the new tunnel and the existing tunnel. And then, the paper analyzed relevant issues, including the intersection point's relationship between the new tunnel and the existing tunnel, the stratum condition, and the current situation of the existing tunnel. Furthermore, this paper researched the construction scheme for the new tunnel within the range of the intersection point and influenced zone, as well as researched the scheme for the strengthening of the existing railway tunnel. Meanwhile, the impacts of blasting vibration on the existing tunnel structure and on the track were strictly controlled. Also, monitoring and measurement as well as information feedback and geological forecast were carried out for both the new one and the existing one, so as to guide field construction, and ensure the existing one's operation safety and the new one's construction safety during tunneling the new one below the existing one.关键词
铁路隧道/下穿隧道/控制爆破/监控量测/设计/施工Key words
railway tunnel/crossing below an existing structure/controlled blasting/monitoring and measurement/design/construction分类
交通工程
