胶凝砂砾石坝渗流场对温度场的影响

Influence of seepage field of cemented sand and gravel dam on temperature field

大华桥胶凝砂砾石围堰实测温度表明,由于堰体防渗、排水设施的简化,渗水降温会对胶凝砂砾石围堰运行期的温度场产生重要影响,在温度场计算分析时不容忽略。充分考虑胶凝砂砾石材料渗流特点和热力学特性,根据渗流和热传导理论,建立了考虑渗流影响的温度场分析微分方程,推导了其有限元数值解法的计算公式,提出了适用于胶凝砂砾石坝的温度场计算方法,并利用大华桥胶凝砂砾石围堰实测数据进行了验证。以该工程为例,通过有限元仿真计算探讨了胶凝砂砾石坝渗流场对温度场的影响规律。分析表明,低温渗透水使浸润线以下区域和浸润线以上部分区域产生较大的降温速率和降温幅度,改变了坝内温度分布状况,使约束区提前产生了较大的基础温差,会对胶凝砂砾石坝抗裂产生不利影响。

The measured temperature of Dahuaqiao cemented sand and gravel(CSG) cofferdam shows that seepage is an important factor in temperature change of the CSG dam due to the simplified anti-seepage and drainage facilities;it can not be ignored in calculation of temperature field. Combining with regularities of measured temperature distribution and variation, and taking a full accout the seepage characteristics and thermodynamic characteristics of CSG material, basing on the theory of seepage and heat conduction, The heat conduction equation of the temperature field considering seepage field and finite elements calculation formula with its settlement is obtained. Accordingly, the numerical calculation method of temperature field is put forward for CSG dam. By taking Dahuaqiao CSG cofferdam for example, the influence of seepage field on temperature field is analyzed. The results show that the seepage water change the temperature distribution in the dam and causes a large temperature drop rate and drop range in areas below the infiltration line and produces a larger temperature difference of dam foundation in advance, which is very disadvantageous to crack resistance.