After how many blows without penetrating deeper, should you remove the drive rod, change locations, and restart the dynamic cone penetrometer (DCP) test?

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The test uses a fall-and-drive cone penetrometer to push a cone tip into soil and measure how far the tip advances with each hammer blow. If, after a fixed number of blows, there is no deeper penetration at a given spot, continuing at the same location won’t yield meaningful data because the resistance could be due to a local hard layer, cobbles, or excessive friction rather than representative soil strength. To get a reliable picture of the soil’s behavior, you relocate to a fresh spot and restart the test. This fixed limit balances efficiency with data quality, ensuring you don’t spend excessive blows on one spot while still collecting enough data from multiple locations to reflect the material properties.