现浇大直径基坑支护能量蓄水管桩能量交换系统研究

Development of Energy Exchange System for Cast-in-place Large Diameter Foundation Pit Retaining Energy Storage Pipe Pile

为提高资源利用效率、响应绿色建筑发展方向,本文对现浇大直径基坑支护能量蓄水管桩的能量交换系统进行研究。结合工程实例进行可利用冷热量计算,运用有限元软件数值建模分析加冰和不加冰情况下能量交换系统周围土体温度场发展规律。结果表明,管桩自下而上对周围土体温度影响范围逐渐增大且分为2个部分,上半部分管桩温度荷载高于原始地温,管桩对地温释放热量,下半部分管桩温度荷载低于原始地温,管桩吸收热量,释放冷量;加冰与不加冰情况下7 h内管桩对土体的影响范围在桩周围1 m以内;无论是加冰还是不加冰的情况下其桩身温度均保持在16~36℃,对桩身钢筋混凝土结构无影响;不同导热系数和比热对于土体温度变化几乎无影响,由于温度荷载所加时间较短,对土体温度变化影响尚未体现出来;原始地温变化对该温度场有显著的影响。综上,桩身温度小幅度变化对自身钢筋混凝土结构无影响,对其周围土体影响可忽略不计,实际应用中需注意防止桩身温度变化幅度过大造成不良影响。

In order to improve the efficiency of resource utilization and respond to the development direction of green building, this paper studies the energy exchange system of energy storage pipe pile of cast-in-place large diameter foundation pit. Combined with the engineering example, the available cold and heat calculation is carried out, and the finite element software is used to numerically model and analyze the temperature field development law of the soil around the energy exchange system with and without ice. The results show that: the influence range of pipe pile on the surrounding soil temperature gradually increases from bottom to top and is divided into two parts. The temperature load of pipe pile in the upper part is higher than the original ground temperature, and the pipe pile releases heat to the ground temperature. The temperature load of pipe pile in the lower part is lower than the original ground temperature, and the pipe pile absorbs heat and releases cooling capacity. The influence range of pipe pile on soil within 7 h with or without ice is within 1 m around the pile. The pile temperature is kept between 16 ℃ and 36 ℃ in the case of with or without ice, which has no effect on the pile reinforced concrete structure. Different thermal conductivity and specific heat have almost no effect on soil temperature change, and the effect on soil temperature change has not been manifested due to the short loading time. The change of original ground temperature has a significant effect on the temperature field. In conclusion, a small change in pile temperature has no influence on the reinforced concrete structure, and the influence on the surrounding soil can be ignored. In practical application, attention should be paid to avoid the adverse effects caused by a large change in pile temperature.