为了研究不同保温模式墙体各功能层在不同季节温度应力的发展情况,在对北京地区典型内外保温墙体的温度场计算基础上,建立了符合墙体典型约束条件下温度应力计算模型,通过计算分析了内、外保温模式对复合墙体各功能层温度应力的影响,并与加气混凝土自保温墙体做了对比.结果表明,墙体内温度应力的大小取决于初始温度(T0)、温度变化(T-T0)及材料弹性模量等因素,当T0=150℃时,冬季墙体主要承受拉应力,夏季受压应力;因此保温墙体外层冬季有开裂、夏季有鼓面的风险.外保温墙体,结构层内温度变化及梯度均较小,温度应力也小;内保温墙体的结构层内温度变化较大,温度应力较大,外保温形式对于建筑物墙体基层有良好的保护作用.由于保温层的隔热作用,使保温层以外各功能层的冬夏温度变化剧烈,相应温度应力也大.
To study the development of the thermal stress in different functional layers of external wall with different thermal insulation modes,based on the calculation results of the temperature field on the external walls with a typical internal or external thermal insulation layer in Beijing,this paper presents an analytical model for temperature stress calculation of the walls under typical constraint condition of walls.Through calculation,the influence of internal and external thermal insulation modes on temperature stress of different functional layers of a composite wall was analyzed and compared with the self-thermal insulated aerated concrete wall.The results show that the thermal stress inside the wall is controlled by the initial temperature(T0),temperature variation(T-T0),and elastic modulus of materials.As T0=15℃,the thermal stress of the wall is in tension in winter and in compression in summer.Therefore,the wall has the potential of cracking in winter and expanding in summer.For the external heat insulation mode,the temperature stress in the structure layer is relatively small due to less temperature variation and gradient in it.For the internal heat insulation mode,the temperature stress in the structure layer is relatively large due to large temperature variation in it.The external heat insulation mode can protect the foundation layer of the wall.Due to heat isolation of the heat insulation layer,the temperature variation of every functional layer other than the heat insulation layer is great,and the corresponding thermal stress is also large during alternation of winter and summer.