<p><p><strong>References:<br></strong><em>Christopher et al. (2010)</em></p><p><strong>Method Summary</strong></p><p>The Dynamic Cone Penetration (DCP) test is used to assess the compaction improvement depth by comparing penetration resistance before and after stabilization. DCP is generally used in pavement foundation layer construction QA process and can measure soil properties up to about 2 meters deep. Difficulties with these test procedures, documented in the literature, occur when large particles or boulders are encountered in the subsurface.</p><p>The DCP test method is described in ASTM D6951. The DCP test method involves driving a cone tip into the soil by lifting an 8-kg sliding hammer to a 575-mm drop height and then releasing it. The total penetration for a given number of blows is then measured and recorded as mm/blow (penetration resistance). ASTM D6951 provides correlations between California Bearing Ratio (CBR) and mm/blow for different soil types.</p><p><strong>Accuracy and Precision</strong></p><p>For subsurface conditions with large boulders or rocks, testing may be difficult. ASTM D6951 indicates that the repeatability standard deviation of the DCP test is less than 2 mm/blow.</p><p><strong>Adequacy of Coverage</strong></p><p>This test can determine the soil condition locally. The required number of tests is dependent on site conditions.</p><p><strong>Implementation Requirements </strong></p><p>The equipment is easy to operate and the test requires minimal training with only some experience.</p><p><strong>General Comments </strong></p><p>Empirical correlations can be used to relate results from the penetration tests to soil engineering properties (e.g., soil strength, bearing capacity, stiffness/modulus, liquefaction susceptibility, etc.). These test methods are useful for QA. These methods can also be used for QC to assess improvements in subsurface conditions with increasing compaction.</p></p>