<p><p><strong>References:<br></strong><em>Bo and Choa (2004)</em></p><p><strong>Method Summary</strong></p><p>Cone penetration test is a popular method to measure the undrained shear strength soil before and after soil improvement. The undrained shear strength can be determined using the equation below.</p><p><img class="aligncenter wp-image-7340" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Equation: S sub u is equal to the ratio of, q sub c minus the product of delta times v, over the product of N times k." width="194" height="87" /><p style="padding-left: 270px;">S_u =undrained shear strength<br>q_c =cone tip resistance<br>N_k=cone factor<br>δυ =overburden stress</p><strong>Accuracy and Precision</strong></p><p>Accuracy and precision of cone penetration tests is dependent on the quality of equipment and testing procedures used.</p><p><strong> </strong><strong>Adequacy of Coverage</strong></p><p>CPTs only yield results for the immediate area of testing. Enough tests should be performed to be considered representative.</p><p><strong>Implementation Requirements </strong></p><p>Proper use of cone penetration testing requires training and experience.</p><p><strong>General Comments </strong></p><p>The testing procedure involves a continuous penetration of the cone into the sub-soils, at a standard penetration rate of 20 mm per second, recording the cone resistance, the sleeve friction, and the penetration pore pressure. CPTs can also be used to estimate the over consolidation ratio of soft clay. The test results can be obtained easily and quickly.</p></p>