隧道施工中,经常会遇到横洞进入正洞或斜井进入正洞的挑顶施工。文章针对V级弱风化围岩灰岩地段,重点论述了横洞(斜井)台阶法与正洞三台阶七步开挖法相结合的挑顶施工方法。施工过程中重点控制对象为横洞钢架转角过度安装与正洞导坑转向三台阶七步开挖。 Tunnel construction, often encounter the hole into the hole or inclined shaft into the hole is the top construction. In this paper, aiming at the weak V grade weathering rock limestone area, this paper mainly discusses the roof top construction method combined with the horizontal hole (inclined shaft) step method and the positive hole three steps seven step excavation method. The key control object in the construction process is the over-installation of the corner of the steel frame of the horizontal hole and the steering of the pilot tunnel to three steps of seven steps of excavation.