季冻区环境温度变化对加筋土挡墙内部温度场的影响研究

EFFECT OF AMBIENT TEMPERATURE CHANGING IN SEASONALLY FROZEN ZONE ON TEMPERATURE FIELD OF INNER REINFORCED-SOIL RETAINING WALL

季冻区环境温度周期性变化对加筋土挡墙性能的影响明显,基于瞬态热传导控制方程,考虑挡墙边界太阳辐射和对流影响,推导了用于分析挡墙温度分布特征的二维有限差分解,通过挡墙模型试验对比验证了数值解的正确性,进而研究面板厚度、路面结构层厚度和墙高等因素对挡墙温度场影响。结果表明:挡墙边界附近温度随环境温度周期性变化呈现波动变化,并明显滞后于环境温度;挡墙内温度变化区域主要位于距面板和路面结构层底部3 m内,且区域化分布特征显著,距面板背部和路面层0~1 m和1~3 m的区域分别为温度变化敏感区和缓和区;增加面板厚度或路面结构层厚度,对挡墙温度区域化特征影响不大,但对温度敏感区的温度滞后效应影响显著;保持墙后尺寸不变,降低墙高对面板附近温度敏感区水平向温度梯度影响不大,而对垂直方向温度梯度影响显著。研究结果将为后续加筋土挡墙长期变形及稳定性分析奠定理论基础。

Cyclic variation of ambient temperature affects significantly the performance of geosynthetics-reinforced soil(GRS)retaining wall in seasonally frozen zone.Herein,on the basis of governing equation of transient heat conduction,the two-dimensional finite difference method is derived and used to analyse the internal temperature distribution of reinforced soil retaining wall under the consideration of solar radiation and convection.The accuracy of numerical analysis is verified by comparison with model wall test results.Furthermore,comparative analysis is carried out to investigate the effect of thickness of facing panels and pavement and wall height on the temperature field of GRS wall.The results show the temperature near boundary of GRS wall fluctuates with the cyclic variation of ambient temperature and is remarkably lagging behind the ambient temperature.The temperature variation inside GRS wall mainly occurs at the range of 3m adjacent to boundary.The temperature distribution tends to be regionalized significantly.The ranges of 0~1m and 1~3m distance from back of facing panels and the bottom of pavement correspond to the temperature sensitive zone and easing zone,respectively.Increasing thickness of facing panels or pavement would not affect obviously the temperature distribute characteristics,however,would make temperature inside sensitive area more lagging behind the ambient temperature.When reducing the wall height with the unchanged width in horizontal direction,the temperature gradient in horizontal direction is not influenced significantly,but it results in remarkable effect on the temperature gradient in vertical direction.The results in this study can pave a firm foundation for the future study of long-term deformation and stability of GRS wall.