采用试片法进行现场测试,探讨了试片极化时间、断电电位采样延迟时间、采样时间间隔和试片与参比电极间距等因素对苏州区域地铁杂散电流干扰下管道断电电位测试结果的影响。结果表明:阴极极化3 h后,裸露面积为6.5 cm²、10 cm²的试片电位趋于稳定;断电延时时间应不小于100 ms;在采样时间间隔1 s与2 s条件下测得两种试片断电电位的偏差不大;试片与参比电极间距越大,试片断电电位偏差值波动越大,在受地铁杂散电流干扰管道正上方采用便携式参比电极对试片开展阴极保护电位测试是可行的。

The field test was carried out by the test piece method, and the influence of polarization time, sampling delay time, sampling interval and the distance between sample and reference electrode on the test results of pipeline power-off potential of subway stray current interference in Suzhou area were discussed. The results showed that after cathodic polarization for 3 hours, the potential of the specimens with exposed areas of 6.5 cm² and 10 cm² tended to be stable. The power-off delay time should be no less than 100 ms. The power-off potentials of the two samples measured at the sampling time interval of 1 s and 2 s had little deviation. The larger the distance between the test piece and the reference electrode, the greater the fluctuation of the power-off potential deviation of the test piece. It was feasible to use portable reference electrode to test the cathodic protection potential of the test piece directly above the pipeline interferted by subway stray current interference.