The standard penetration test

September Learn how and when to remove this template message. When the test is carried out in granular soils below groundwater level, the soil may become loosened. The number of hammer strikes it takes for the tube to penetrate the second and third 6 inch depth is called the 'standard penetration resistance', or otherwise called the 'N-value'. The usefulness of SPT results depends on the soil type, with fine-grained sands giving the most useful results, with coarser sands and silty sands giving reasonably useful results, and clays and gravelly soils yielding results which may be very poorly representative of the true soil conditions. Now place a straight edge across the bore touching the A-drill rod. In cohesive soil the test involves driving a 50mm diameter split-barrel spoon sample tube into the ground to recover a disturbed sample. The standard penetration test SPT is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil.

Keep in mind, the target organization may not be the customer. Retrieved from " http: It is the responsibility of each tester to verify the laws for each region they are testing in before they begin testing because it will be the tester who ultimately will have to answer for any transgressions.