研究结论：风险性评估是在目前勘察手段有限的条件下正确评价地下水风险的合理选择; 本文提出的以概率分析为基础的地下水风险评估是以往以定量计算为重点的水文地质条件评价的重要延伸和完善; 地下水涌水量及涌水方式、地下水压力、地下水变化导致产生围岩稳定问题、水质改变、地下水疏排导致的环境改变是地下水风险的主要因素; 水文地质计算中常因地下水富水性不均导致局部出现较明显误差，风险性评估能够减小这种误差导致局部重大涌水未能预测出现的风险。

Research conclusions:The risk assessment is the reasonable way for correcting assessing the risk of the underground water under the condition that the current survey means is limited． The risk assessment of the underground water based on probability analysis presented in this paper is the important development and improvement of the previous assessment of hydrogeologic condition by taking quantitative calculation as the key point． The main factors of the underground water risk include the unstable surrounding rock and change of water quality caused by the volume and way of water bursting，the pressure of the underground water and the change of the underground water as well as the environment change caused by draining the underground water． The obviously local error often happens in the calculation of the hydrogeologic condition because of the uneven watery of the underground water． Conducting the risk assessment can reduce the risk of the big local water bursting caused by the error．