The shield method is widely used in underwater tunnel construction. However, the shield construction process faces many uncertain risk factors that increase the level of safety risk during shield tunnel construction. Therefore, risk assessment has become a necessary task in the early stages of tunnel construction. In this study, a new risk assessment model for underwater shield tunnel construction is proposed that combines a normal cloud model with an entropy weight method. The model contains 20 assessment indexes and gives the range of each index corresponding to different risk levels, which comprehensively reflects the influencing factors of risk. By using a normal cloud model, the fuzziness and randomness of risk assessment data are taken into account effectively, and the reliability of assessment results is increased. Based on an entropy weight method, the rules and characteristics of the evaluation data in the model are considered, and the weight coefficient of the evaluation index is determined to avoid the subjectivity of the expert weight method. The risk assessment model is applied using the Xiangjiang shield tunnel as an example. The results show that the overall construction risk level of the Xiangjiang tunnel is level II, which is consistent with the site risk situation and shows that the model can objectively and accurately evaluate the construction risk level of an underwater shield tunnel.

盾构法广泛用于水下隧道施工。但是，盾构施工过程中面临许多不确定的风险因素，这些风险因素增加了盾构隧道施工期间的安全风险水平。因此，风险评估已成为隧道建设初期的一项必要任务。在这项研究中，提出了一种新的水下盾构隧道风险评估模型，该模型将常规云模型与熵权法相结合。该模型包含20个评估指标，并给出了每个指标对应于不同风险水平的范围，从而全面反映了风险的影响因素。通过使用正常的云模型，有效地考虑了风险评估数据的模糊性和随机性，并提高了评估结果的可靠性。基于熵权法，考虑模型中评估数据的规则和特征，确定评估指标的权重系数，避免专家权重法的主观性。以湘江盾构隧道为例，应用风险评估模型。结果表明，湘江隧道总体施工风险等级为Ⅱ级，与现场风险情况相吻合，表明该模型能够客观，准确地评价水下盾构隧道施工风险等级。以湘江盾构隧道为例，应用风险评估模型。结果表明，湘江隧道总体施工风险等级为Ⅱ级，与现场风险情况相吻合，表明该模型能够客观，准确地评价水下盾构隧道施工风险等级。以湘江盾构隧道为例，应用风险评估模型。结果表明，湘江隧道总体施工风险等级为Ⅱ级，与现场风险情况相吻合，表明该模型能够客观，准确地评价水下盾构隧道施工风险等级。