控制冻土融化容许值的建筑物通风管基础计算方法

An approach for computing the ventilated foundation of buildings based on controlling the permissible value of permafrost thawing

根据传热理论,在现有JGJ118—98《冻土地区建筑地基基础设计规范》中采用的无通风管基础的冻土地基的最大融化深度的计算公式基础上,推导出有通风管基础按容许地基土逐渐融化原则设计的冻土地基最大融化深度的计算公式,首次提出了等效地面温度和等效地面温度系数的概念。首次建立室内采暖条件下通风管复合基础的传热数学模型,并在此模型基础上采用有限单元法对通风管复合基础进行数值模拟分析结合理论推导的方法,得出不同室内地面温度、不同通风管间距时的通风管基础中心下的温度沿深度分布曲线及54个等效地面温度数据,依据最小二乘法原理对以上数据拟合出工程广泛采用的通风管直径为300mm的通风管基础的等效地面温度系数计算公式,从而提出建筑物通风管基础通风面积计算方法,由实际工程设计验证了该计算方法的可靠性与实用性。

Based on the heat-transfer theory, a calculation formula is derived for the maximum thawing depth of frozen ground under ventilated foundations. From the design viewpoint in allowing gradual thawing of the foundation soil, both the concept of equivalent floor temperature and the associated temperature coefficient are presented. Through theoretical analysis and numerical simulation, 54 equivalent floor temperatures and the temperature distribution curves with depths are obtained for different inner floor temperatures and spaces between vent-pipes. The calculation method for the equivalent floor temperature factor of ventilated foundations with vent-pipes of a 300mm diameter is obtained by using a compound foundation model and the method of least squares. The design method for areas of ducts that control the permissible value of permafrost thawing is obtained. The reliability and practicability of the calculation method is validated in practical engineering designs.