This paper aims at developing an efficient numerical model to numerically reproduce the fire-induced spalling process taking place in concrete and to investigate the underlying mechanism of thermal spalling. To deal with complex crack patterns and with ease of extending to multi-physics problem, phase field method is employed for crack modeling. The primary objective of this manuscript is to develop a coupled thermo-hydro-mechanical-phase field model and the numerical solution framework. The effects of length scale parameter, staggered solution methods, and related factors on mechanical fields, as well as the impact of fracture on mass transfer and heat conduction are investigated. It is concluded that spalling is a result of combined thermal expansion and vapor pressure, among which thermal effect plays a major role and vapor pressure accelerates the occurrence of spalling.

本文旨在开发一种有效的数值模型，以数值方式再现混凝土中发生的火灾引起的剥落过程，并研究热剥落的潜在机制。为了处理复杂的裂纹模式并易于扩展到多物理场问题，采用相场法进行裂纹建模。这份手稿的主要目标是开发一个耦合的热-水-机械-相场模型和数值求解框架。研究了长度尺度参数、交错求解方法和相关因素对力学场的影响，以及断裂对传质和热传导的影响。得出的结论是，剥落是热膨胀和蒸汽压力共同作用的结果，