为综合考虑岩土参数的空间变异性以及前期地质勘查所获取钻孔数据的确定性，提升基坑开挖变形风险评估的准确性，提出基于约束随机场的基坑开挖变形概率评估方法。所提方法利用克里金（Kriging）理论和随机场理论，生成考虑地勘钻孔数据的约束随机场，并结合数值分析和蒙特卡洛（Monte-Carlo）方法建立基坑开挖的概率评估模型，分析参数空间变异性对基坑开挖引起的环境效应和围护结构变形的影响规律。与传统确定性分析和基于传统随机场的概率分析进行对比，结果表明：基于约束随机场的概率分析方法能够很好地避免传统确定性分析低估风险以及传统随机场方法高估风险的问题，从而更合理地评估工程风险。研究成果可以为进一步制定基坑开挖风险的应对措施提供有益参考。

In order to consider the spatial variability of geotechnical parameters and the determinism of the borehole data obtained from the preliminary geological survey, and improve the accuracy of deformation risk assessment, a method of braced excavation deformation probability assessment based on constrained random field was proposed. Kriging theory and random field theory were used to generate a constrained random field considering the borehole data. Numerical analysis and Monte-Carlo method were then adopted to establish a probabilistic assessment model, and analyzed the influence pattern of parameter spatial variability on the environmental effects and enclosure structure deformation caused by braced excavation. Compared with the traditional deterministic analysis and the probabilistic analysis based on the traditional random field, the results show that the probabilistic analysis method based on the constrained random field can avoid underestimating the risk by the traditional deterministic analysis and overestimating the risk by the traditional random field method, so as to evaluate the risk more reasonably. The research results can provide useful references for further development of countermeasures for braced excavation risks.