According to the technical standards for building drilling, the soil layer generally does not exceed 1.0m, and the main bearing layer generally does not exceed 0.5m. ..
Generally speaking, the length of core tube is less than 2.0m for rock stratum and less than 2.0m for soft rock.
It should be noted that some strata are relatively broken, and if the footage is too large during drilling, it is easy to cause the gravel in the core tube to wear with the rotation of the core tube, thus reducing the coring speed and affecting the quality of core drilling. Therefore, under complex geological conditions, controlling the depth of footage is also one of the important measures to ensure the heart rate.