山区高速公路隧道穿越特大型溶洞施工技术

Construction Technologies for Highway Tunnels Crossing through Extra-large Karst Caves in Mountain areas

为解决隧道穿越特大溶洞施工中存在的技术难点,保证隧道工程的实体质量,以白须公隧道为研究对象,通过对溶洞岩体地质状况实施勘测,对岩体的岩层走向和节理分布情况实地调查,根据溶洞的实际状况和收集的数据确定溶洞的处理方案。提出溶洞底部采用桩基处理,在基础上构建承台及支撑墙,溶洞底与隧道结合处采用横向联系梁连接,对溶洞靠隧道一侧的侧壁及顶部围岩采用清理和喷锚加固等处理措施,有效解决了隧道穿越特大溶洞技术难题。

An extra-large karst cave is encountered during the construction of Baixugong tunnel. The geological condi- tions of the karst cave are investigated and the strike and joint distribution of the rock mass are surveyed. Countermeas- ures are determined according to the actual conditions of the karst cave and the geological data collected. Technologies, including executing pile foundations at the bottom of the karst cave, setting pile caps and supporting walls on founda- tions, using transverse connection beams to combine the karst cave bottom and the tunnel, and clearing and ＂shotcreting and rock bolting＂ reinforcement of the side wall and roof of the karst cave, are proposed. In the end, the tunneling cros- ses through the extra-large karst cave successfully.