浅层地温剖面曲线拟合法估算热扩散系数

从浅层岩土热传导和热扩散理论出发,推导出一种半无限均匀岩土地温变化的数学模型,通过利用该模型拟合实测地温剖面曲线,可以求取浅层岩土整体的热扩散系数以及地表年平均温度、温度变幅、初相等大地温度特性参数.两个实例的计算结果表明,所采用的理论模型能够很好地拟合地温实测剖面曲线,通过该方法所求得的浅层岩土热扩散系数与参考文献给出的值很接近,说明该方法是可行的.该方法建立在可靠的理论和清楚物理机制之上,简单有效,可以在实际工作中推广应用.

Estimation of thermal diffusivity using subsurface temperature profile curve fitting algorithm

Based on the theory of heat transfer and thermal diffusion in subsurface soil,a mathematical equation was derived for describing the temperature fluctuation in a semi-infinite homogeneous soil,this equation can be used to fit the temperature profile curves of drill hole to estimate the gross thermal diffusivity of subsurface soil and ground temperature parameters,such as the mean surface temperature,the annual temperature amplitude at the surface,the day of minimum surface temperature.Results of two examples show that the theoretical model fits the measured temperature profile curve very well,and the diffusivity values of subsurface soil obtained by the new method are rather close to that from references,indicating that the algorithm is feasible.The algorithm can be widely applied in practical work since it is simple,convenient and effective,and based on the reliable theory and clear physical mechanism.