Aplicabilidad del penetrómetro cónico en la determinación del límite líquido

Abstract

The Casagrande cup test is the most common method used to determine the liquid limit in Ecuador. However, the ASTM D4318-00 standard related to the Casagrande method has shown that there is variability in the results obtained from the same soil when these tests are performed by different laboratorians, which implies that different results can be obtained from the same soil. In parallel there is a procedure known as the penetration cone method, which consist in dropping a cone with dimensions specified by the BS 1377: 2-1990 standard for a 5 seconds period on a sample of soil to measure the penetration. This procedure is less susceptible to the operator which is advantageous. The cone method is not a standard procedure in Ecuador, so it is necessary to conduct studies on the region. Hence, the present investigation focuses on comparing both methods, using three different soils from the region. By statistical procedure that measures the sample size necessary to compare means of 2 samples is determined the number of tests that must be performed in each of the soils to compare the liquid limits. The results show that the penetration cone method is applicable to obtain the liquid limit. It is important to mention that a significant difference is detected in the liquid limit, the difference is between 6 and 9 percentage points between both test methods, which could change the interpretation of soil characteristics.