在分析混凝土表面裂缝特点的基础上，针对受寒潮袭击中的大体积混凝土，提出表面裂缝问题的半无限平面假设。利用混凝土传热的延迟性质，研究了任意降温过程中半无限平面问题无限平面化的条件。采用叠加原理，提出了环境温度任意下降时混凝土表面温度及表层温度计算的新方法。利用400mm×400 mm×220 mm块状试件，构造了混凝土表面开裂问题的半无限平面模型。在室外环境下，对混凝土表面温度与表层温度进行了连续测量，并对该方法进行了验证。试验结果表明，在环境温度单调下降的条件下，对混凝土受寒潮袭击时的半无限平面问题进行无限平面化处理是可行的。

Almost all the cracks in mass concrete are surface cracks. Full-section cracks and deep-level cracks are mainly developed from early surface cracks. This paper describes the characteristics of the surface cracks of mass concrete firstly. Then a semi-infinite plane model for surface temperature calculation is compared with infinite model. The temperature of surface zone in mass concrete under different boundaries is controlled by semi-infinite model, and is transferred to and calculated by an equivalent infinite model under certain conditions. If the temperature declining duration of air is no more than the critical time when the disturbed front perforates half-thickness of the infinite plate, it may be expressed as multi-line process approximately, and most importantly the temperature in surface zone of concrete can be calculated with the formula educed by infinite model. With 400 mm × 400 mm × 220 mm concrete specimens, the temperatures in surface zone are experimentally researched under outside environment, which has attested the method presented. It is also found that the new method to describe declining process of air temperature is more accurate than the method prevailing, and there does exist an opportunity to develop a physical model for the temperature process of mass concrete within a short period of time.