Displacement is the most intuitive reflection of the comprehensive behavior of concrete dams, especially the time effect displacement, which is a key index for the evaluation of the structural behavior and health status of a dam in long-term service. The main purpose of this paper is to establish a state space model for separating causal components from the measured dam displacement. This approach is conducted by initially proposing two equations, which are the state and observation equations, and model parameters are then optimized by the Kalman filter algorithm. The state equation is derived according to the creep deformation of dam concrete and foundation rock and is used to preliminarily predict the dam time effect displacement. Considering the generally recognized three components of dam displacement, the hydraulic-seasonal-time (HST) model is used to establish the observation equation, which is used to update the time effect displacement. The efficiency and rationality of the established state space model is verified by an engineering example. The results show that the hydraulic component separated by the state space model only contains the instantaneous elastic hydraulic deformation, while the hysteretic elastic hydraulic deformation is divided into the time effect component. The inverted elastic modulus of dam body concrete is an instantaneous value for the state space model but a comprehensive reflection of the instantaneous and hysteretic elastic deformation ability for the HST model, where the hysteretic elastic deformation is a part of the hydraulic component. For the Xiaowan arch dam, the inverted values are 42.9 and 36.7 GPa for the state space model and HST model, respectively. The proposed state space model is useful to improve the interpretation ability of the separated displacement components of concrete dams.

位移是混凝土大坝综合性能的最直观反映，尤其是时效位移，是评价长期服务大坝结构性能和健康状况的关键指标。本文的主要目的是建立一个状态空间模型，用于从测量的大坝位移中分离因果分量。该方法首先提出状态方程和观测方程两个方程，然后通过卡尔曼滤波算法对模型参数进行优化。根据大坝混凝土和基岩的徐变变形推导出状态方程，用于初步预测大坝时间效应位移。考虑到公认的大坝位移的三个组成部分，水力-季节-时间（HST）模型用于建立观测方程，用于更新时间效应位移。通过工程实例验证了所建立状态空间模型的有效性和合理性。结果表明，状态空间模型分离的水力分量仅包含瞬时弹性水力变形，而滞回弹性水力变形被划分为时间效应分量。坝体混凝土的反演弹性模量是状态空间模型的瞬时值，是HST模型瞬时和滞回弹性变形能力的综合反映，其中滞回弹性变形是水力分量的一部分。对于小湾拱坝，倒置值为 42.9 和 36。状态空间模型和 HST 模型分别为 7 GPa。所提出的状态空间模型有助于提高混凝土坝分离位移分量的解释能力。