TEM中心回线法计算考虑关断时间的全区视电阻率

详细推导了TEM法中心回线装置发射电流为斜阶跃波形条件下全区视电阻率迭代反演计算方法。对正演过程中对关断时间的积分采用了解析表示。对反演过程中求导运算,通过变量变换,将对电阻率的求导变换为对时间的求导,从而也给出简单的解析关系。避开了数值积分运算和差分替代导数的近似,提高了计算精度和速度。为克服迭代反演过程中要多次计算概率积分的耗时问题,采用标准数据库的方法一劳永逸地加以解决,也大大提高了计算精度和速度。对实测资料进行了计算,并通过算例对一些问题进行了讨论。

ALL-TIME RESISTIVITY CALCULATION IN CONSIDERATION OF TIME-OFF USING THE CENTRAL TEM LOOPS METHOD

The all-time apparent resistivity iteration inverse method was deduced in detail based on the current slanting wave of the TEM central loops unit.In the forward process,the turn-off time integral was represented analytically.The resistivity derivation could be transformed to the time derivation through the variable transformation in the inverse process.The calculation precision and speed were promoted by avoiding the numerical integral and differential calculation used in approximating the derivation.The standard database method was used to decrease the calculation time of probability integral in the inverse process of iteration as well as to improve the precision and speed.Then the survey data were processed and some problems were discussed on the basis of a few calculation examples.