Abstract: Thermal parameters vary with the temperature. In order to understand the axial error of double-metal marks which is caused by the change of thermal parameters under the condition of thermomechanical coupling, the integral formula is derived based on the theory of elasticity. According to the surface and deep temperature determined by relevant literature, double-metal marks of different depths (30 m, 50 m and 100 m) in three typical areas are selected to calculate the axial error caused by temperature difference in all situations. Research shows that the maximum measurement error caused by temperature effect on elastic modulus is in the order of 10^-2 mm, even for the 100 m long double-metal marks, which can be ignored.

Key words: double-metal marks, elastic modulus, linear expansion coefficient, temperature variation

摘要： 为了解热力耦合条件下由于温度引起的热力参数变化带来的双金属标轴向误差，根据弹性力学理论推导了积分公式。根据相关文献确定的地表和深部温度，选择3个典型地区30 m、50 m和100 m不同深度的双金属标，计算了各种情况下由于温差导致的双金属标轴向误差。研究表明，即使对于100 m长的双金属标，由于弹性模量温度效应引起的最大测量误差都在10^-2 mm数量级，完全可以忽略不计。

关键词: 双金属标, 弹性模量, 线膨胀系数, 温度变化