郑万铁路湖北段巴东至香炉坪隧道群在穿越可溶岩地区地质勘察期间，深孔钻探揭示到能听见水声、伴有冷风冒出、超过80 m的巨型半充填溶洞等。为解决上述不良地质问题，在经过区域水文地质调查及系统的地下水动力分析，推测该溶洞底部为暗河，施工图设计阶段对初步设计阶段既定线路方案进行优化。由于受车站位置、标高及线路纵坡等因素控制，无法从竖向空间进行综合调整，进而从平面上提出5种线路方案，并从主要不良地质、岩溶发育程度、围岩级别、辅助坑道、施工风险、工程投资等方面进行综合比选，推荐出施工风险相对较低、投资相对较少的线路取直且绕避暗河的D8K线路方案。施工开挖揭示表明，隧道成功避开岩溶强烈发育区的巨型含水地下暗河，巴东至香炉坪隧道群岩溶地质选线方案是成功的。
The deephole drilling results of the
BadongXiangluping tunnel group on the ZhengzhouWanzhou railway crossing karst area revealed multiple adverse
geological conditions, including waterflow sound, cold wind leakage, and giant
haftfilled karst with a diameter exceeding 80 m. Thus,
a regional hydrogeological survey and systematic groundwater hydrodynamic analysis
are conducted. The findings indicate that the karst cave bottom is an
underground river. Consequently, the existing tunnel route scheme for the
preliminary design phase is improved in the construction drawing. Due to the
control of station location, elevation, and longitudinal slope of the route, it
is impossible to conduct wideranging adjustments on
threedimensional space. For that reason, five route
schemes are proposed for the plane. Finally, a thorough comparison and
selection of main adverse geologies, karst development degree, surrounding rock
grade, auxiliary tunnel, construction risk, and project investment are carried
out. Considering construction risk and relative investment, the D8K route
scheme that avoids the underground river is recommended. Overall, the
construction excavation results show a successful route selection.
