Standard penetration test correlations for Las Vegas soils
Standard penetration tests (SPT) are used to approximate soil properties including the consistency, cohesion and the internal angle of friction. Due to the frequency of cemented sands, gravel and clay in the Las Vegas Valley, the generally accepted SPT correlations vary from actual local conditions. The following discussion will present SPT correlations, based on field test data, for consistency, cohesion and the internal angle of friction, specifically for the Las Vegas Valley. The Las Vegas soil correlations are compared to general soil correlations; Sampling methods other than the Standard Penetration Test are used to estimate soil characteristics. The SPT uses a 1.375 inch inside diameter sampler with a 150# hammer dropped 30 inches. The driven sample method, often used in Las Vegas, utilizes a 2.625 inch inside diameter sampler with a 350# hammer dropped 30 inches. Correlations, relative to Las Vegas soils, between the two tests are discussed.