The shrinkage separation is one of the key factors restricting the development of concrete-filled steel tube (CFST) arch bridge. In this paper, its mechanism and evaluation method concerning multiple factors, including structure, environment, material and construction were investigated. Firstly, the hydration process of in-tube concrete was simulated using the hydration degree as a basic state parameter. Then with the consideration of energy and mass conservation, as well as the moisture and heat transmission effects, the temperature and relative humidity fields, early-age mechanical properties, basic creep, and total deformation of in-tube concrete were further calculated. On the basis, in accordance with the stress criterion and displacement coordination, a multi-field (hydro-thermo-hygro-constraint) coupling model was finally established, taking the ratio of normal stress to bonding strength at the steel-concrete interface as the shrinkage separation risk index. The simulation results obtained from the model were in good agreements with the full-scale CFST model test.

中文翻译：

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钢管混凝土拱桥收缩分离预测：多因素耦合模型


收缩分离是制约钢管混凝土拱桥发展的关键因素之一。本文从结构、环境、材料、施工等多因素对其作用机理和评价方法进行了研究。首先，以水化度作为基本状态参数，模拟管内混凝土的水化过程。然后考虑能量和质量守恒以及湿热传输效应，进一步计算管内混凝土的温度场和相对湿度场、早期力学性能、基本徐变和总变形。在此基础上，根据应力准则和位移协调，最终建立了以钢-混凝土界面正应力与粘结强度之比为多场（水-热-湿-约束）耦合模型。收缩分离风险指数。模型的模拟结果与足尺钢管混凝土模型试验吻合较好。