铁路隧道超近距离下穿输水渠施工安全控制技术研究

A Study of the Construction and Safety Control Techniques for a Railway Tunnel Under-Crossing the Water-Delivering Ditch at a Short Distance

蒙华重载铁路城烟隧道在进口下穿输水渠,最小距离仅为2.67m,且由于地形条件的限制只能采用反向施工。针对超近距离下穿施工难点,提出了洞外采用多道防护、小导洞出洞、超前大管棚预支护、输水渠加固、控制爆破等综合安全控制技术。现场变形监测结果表明:拱顶沉降和水平收敛稳定速度均较快,且量值较小;地表沉降最大值为10.59mm,红线渠没有发生任何开裂和渗漏现象,表明安全控制措施合适。

T he Chengyan Tunnel of the Menghua heavy-duty railway has to under-cross a water-delivering canal at the inlet,with the closest distance between them only 2.67m. Only the reverse-construction method can be adopted here due to the limitationsof the terrain conditions. With the great difficulty in performing the super-short-distance construction taken into consideration,put forward in the paper are some comprehensive safety control techniques？such as the adoption of multi-course protectionoutside the cave, the small heading method at the move-out stage, the advanced large-tube-shed supporting, consolidatingthe water-delivering canal, the controlled blasting, etc. T he monitored site deformation results show th a t： both the stabilizingrate of the crown settlement and the horizontal convergence are quick and their quantity is sm all; the maximum of the groundsettlement is 10. 59mm ; no cracking and no leakage are observed in the water-delivering canaU which proves that the adoptedsafety control techniques are appropriate.