云南登楼山隧道横穿水热活动强烈的小江断裂带，为利用地质分析手段评价隧址区水热活动规律，进而探讨线性工程热害评价方法，在已获得的地质资料的基础上，分析小江断裂带区域发育规律，然后对隧址区小江断裂系地质构造整体展布规律以及地质构造的优势方位与热水地表出露分布特征的空间关系进行梳理。利用地表热显示的氢氧同位素高程效应和二氧化硅温标，对隧址区热水的补给高程、热储温度以及循环深度进行分析，确定隧址区热水的整体运移特点。此外，综合分析隧址区的测温钻孔数据和水化学数据，确定隧道进出口附近象鼻温泉和龙潭营温泉2处热水运移演化模式。结果表明： 距离登楼山隧道进出口较近的象鼻温泉和龙潭营温泉的运移路径与隧道轴线不仅在空间上无交集，且热水运移的地层与隧道穿越地层也不同，故判断出2处热水导致隧道遭遇热害风险的可能性较低； 但测温钻孔中的地温梯度显示，隧道穿越山体部分虽无地表热显示，但在深度大于450 m的埋深部位仍然存在轻微热害的风险。

The Dengloushan tunnel in Yunnan province, China, crosses the Xiaojiang fault with strong hydrothermal activity. The present study aims to evaluate the hydrothermal activity pattern at the tunnel site through geological analysis and subsequently evaluate the linear engineering thermal hazard. The regional development pattern of the Xiaojiang fault is analyzed based on the obtained geological data. Furthermore, the distribution pattern of the overall geological structure of the Xiaojiang fault system at the tunnel site and its spatial relation with the hot water distribution on the surface are evaluated. The recharge elevation, heat storage temperature, and circulation depth of hot water in the tunnel area are analyzed using the elevation effect of hydrogen and oxygen isotopes and the silica temperature scale. The overall migration characteristics of hot water in the tunnel area are also determined. Additionally, the thermal borehole data and hydrochemical data at the tunnel site are comprehensively analyzed. Moreover, hot water migration and evolution models for the Xiangbi and Longtanying hot springs near the tunnel entrance and exit, respectively, are determined. Results show that the migration paths of both the hot springs have no intersection with the tunnel axis in space and that the strata of hot water migration are different from those crossed by the tunnel. Thus, the possibility of heat damage owing to hot water at the two places is low. However, the geothermal gradient in the temperature measurement in the borehole shows that although no surface heat is detected in the part of the tunnel through the mountain, a slight risk of thermal hazard still exists at a depth of >450 m.