Previous research of segmental joints are mainly based on experimental and theoretical methods; few studies have focused on refined numerical model. Therefore, a refined numerical model is established in which eight‐node solid element and three‐dimensional beam element are adopted to simulate joint structures and reinforcement, respectively, and bolt preload is considered. Then, the numerical model is verified with full‐scale tests and applied to analyze the influence of joint deformation and bolt preload. It is confirmed that (a) the numerical model can reproduce joint deformation process with good accuracy; (b) bolt stress are controlled by tensile action caused by joint opening and bending action caused by joint vertical displacement; (c) the changes of joint deformation with bending moment can be divided into three stages; bolt preload has no effect on the change of joint deformation with bending moment but has significant impact on the value of joint deformation in each stage.