单洞螺旋隧道平曲线半径选择及运营安全对策

Selection of Flat Curve Radius and Operation Safety Countermeasures about Single Spiral Tunnel

山区高等级公路在路线布设时往往因条件受限而需要在较短路段集中升坡或降坡。螺旋展线因比回头展线具有更好的线形指标而被采用,在避开不良地质,克服大高差、大纵坡方面取得了较好的效果。通过对云南某二级公路新安螺旋隧道的控制线形安全性指标:停车视距、曲线内侧车道横净距、临界最小圆曲线半径及运营安全的检验计算,来保证隧道平面线形的安全性,以寻求一个具有代表性的小半径螺旋曲线隧道安全的线形方案及运营安全对策。

On routing of mountain highway,some concentrated elevating or falling gradient of shorter highway section is needed. Spiral line development is used on account of the better alignment indices compared with turn line development. Good effects are achieved in the field of avoiding the bad geographical, overcoming large height difference and longitudinal slope. However the technical indices adopted in the alignment scheme are met for the safety operation. The Xin＇an spiral tunnel of the second-class highway of Shuifu to Suijiang is taken as a study case. The controlling alignment safety indices such as stopping sight distance,curve inner lane lateral clear spacing,critical minimum radius of horizontal curve and operation safety are checked and calculated to ensure the safety of horizontal alignment. On the basis of the controlling alignment safety indices for the second-class highway spiral tunnel,an operation safety countermeasure is proposed.