Although you need to take out the drill pipe, the soil is relatively complete, and the depth you measure is only 30m, which is relatively more accurate.
Although you need to take the drill pipe out, the soil is relatively complete, and you measure disburseed depth of only 30m, relatively high accuracy of the test.
Although you need to take out the drill pipe, the soil is relatively complete, and the depth you measure is only 30m, so the accuracy of the test is much higher<br>