<p><p><strong>References:<br></strong><em> Schaefer et al. (2016)<br>Massarsch and Fellenius (2001)<br>Massarsch and Fellenius (2005)<br>Massarsch and Heppel (1991)<br>Mitchell (1981)<br>SHRP 2-Phase I Technology Assessment (2008)</em></p><p><strong>Method Summary</strong></p><p>The Cone Penetration Test (CPT) is a field method to directly measure the soil resistance. In this test a small diameter cone is pushed into the ground at a constant rate. The tip resistance and the sleeve friction are measured with depth either electronically or mechanically (not typically used anymore). While this test is unable to retrieve samples, it provides a continuous soil profile. The measured values can be related to produce a soil classification and strength parameters. CPTs can be performed on all types of soils except for very coarse granular soils or soils with large debris. Different types of CPT tests are available. Research may be required to determine the reliability of each method and which method is more applicable to the project objectives.</p><p><strong>Accuracy and Precision</strong></p><p>CPT testing provides a continuous boring log that is more considered to give a more representative and accurate soil profile than SPT tests. CPT testing cannot be used to retrieve samples for laboratory tests.</p><p><strong>Adequacy of Coverage</strong></p><p>The frequency of CPT tests is based on size of construction, number of machines in operation, complexity of ground, and importance of the structure being built. Depending on the importance of the project, more or less CPT tests can be performed.</p><p><strong>Implementation Requirements </strong></p><p>CPT tests are a commonly performed procedure. However, the test requires experience to push the cone and to understand when reasonable results are being obtained. CPT measurements should be taken at the center point between vibrocompaction points (i.e., at the center of the triangular or square grid shapes).</p><p><strong>General Comments</strong></p><p>The CPT results are an indicator of the ability of the soil foundation to support the service loads and prevent liquefaction. CPT cone resistance values can be correlated to produce relative density values. The strength or elastic modulus can be found as a function of the CPT cone resistance value, which can then be used to calculate bearing capacity or generate a strain profile and expected settlement. Massarsch and Fellenius (2001, 2005) describe how to adjust CPT values for overburden and factors which affect the recorded values. Commonly, construction specifications will mandate a particular CPT cone resistance value for the in-situ cohesionless soil. The required CPT values will vary depending on the project.</p></p>