Cone penetrometer test is also called cone penetration test, usually abbreviated as CPT. This technique is used to gauge the geotechnical engineering qualities of soils. Also, it is used in determining the delineation of stratigraphy of soils. CPT was invented in the 1950s in Delft. The scientists that invented the process were researching soil soils at the Dutch soil mechanics laboratory. This is worth knowing about cone penetrometer test for soil.
This test is at times called Dutch cone test due to its origin. Despite being invented and developed in Europe, CPT is now a recognized technique that is used widely in the world to investigate soils. This technique is in most cases used in ground compaction activities. The market has a number of mechanical and electric CPTs, but the widely used method is the electric cone.
CPT involves the use of a conical tip that is pushed into the ground at the rate of 2 centimeters per minute. The conical tip is designed with an apex angle of 60 degrees and a diameter of 35.7 millimeters. The steel rod that connects to the pinecone has the same diameter of 35.7 millimeters as the pinecone. The rate at which the pinecone is pushed into the soil can be varied between 1.5 and 2.5 centimeters per second.
As the pinecone continues to be pushed into the soil, the penetration resistance at the tip and along the shaft is measured. The section of the shaft that experiences friction is referred to as the friction sleeve and it is located exactly after the pinecone. The surface area of the friction sleeve is usually 15, 000 square millimeters.
An electric CPT has a transducer which is used to measure and record the friction. The name CPTU is used to refer to a CPT probe that has a pore-water pressure sensor. In CPTU, the filter ring of the pore-water component has to be saturated with water completely when it is being used. Otherwise, the piezo-transducer will take erroneous recordings.
One can include other types of sensors in the CPT in order to measure other elements of the ground that is being worked on. For example, one can include vibration sensors that will help determine acceleration and vibration velocity. CPT is a standardized operation whose results are not dependent on the operator like is the case with SPT. Since CPT results are independent of the operator, it implies that they are reproducible.
CPT functions by measuring sleeve friction and pinecone resistance in order to ascertain the friction ratio, which is normally denoted as FR. Variations in lateral earth pressure in the ground is reflected by sleeve friction. Hence, this can be used in investigating how soil compaction affects the condition on stress. Also, effective overburden pressure can be immensely affected by pinecone and sleeve friction measurements.
The purpose of CPT is to gather information about soil variation and stratification in both horizontal and vertical directions. Friction ratio is used in identifying the type of soil and is used in providing information on alternative compaction techniques. On the other hand, measuring excess pore-water pressure is used in ascertaining layers and seams in fine-grained materials.
This test is at times called Dutch cone test due to its origin. Despite being invented and developed in Europe, CPT is now a recognized technique that is used widely in the world to investigate soils. This technique is in most cases used in ground compaction activities. The market has a number of mechanical and electric CPTs, but the widely used method is the electric cone.
CPT involves the use of a conical tip that is pushed into the ground at the rate of 2 centimeters per minute. The conical tip is designed with an apex angle of 60 degrees and a diameter of 35.7 millimeters. The steel rod that connects to the pinecone has the same diameter of 35.7 millimeters as the pinecone. The rate at which the pinecone is pushed into the soil can be varied between 1.5 and 2.5 centimeters per second.
As the pinecone continues to be pushed into the soil, the penetration resistance at the tip and along the shaft is measured. The section of the shaft that experiences friction is referred to as the friction sleeve and it is located exactly after the pinecone. The surface area of the friction sleeve is usually 15, 000 square millimeters.
An electric CPT has a transducer which is used to measure and record the friction. The name CPTU is used to refer to a CPT probe that has a pore-water pressure sensor. In CPTU, the filter ring of the pore-water component has to be saturated with water completely when it is being used. Otherwise, the piezo-transducer will take erroneous recordings.
One can include other types of sensors in the CPT in order to measure other elements of the ground that is being worked on. For example, one can include vibration sensors that will help determine acceleration and vibration velocity. CPT is a standardized operation whose results are not dependent on the operator like is the case with SPT. Since CPT results are independent of the operator, it implies that they are reproducible.
CPT functions by measuring sleeve friction and pinecone resistance in order to ascertain the friction ratio, which is normally denoted as FR. Variations in lateral earth pressure in the ground is reflected by sleeve friction. Hence, this can be used in investigating how soil compaction affects the condition on stress. Also, effective overburden pressure can be immensely affected by pinecone and sleeve friction measurements.
The purpose of CPT is to gather information about soil variation and stratification in both horizontal and vertical directions. Friction ratio is used in identifying the type of soil and is used in providing information on alternative compaction techniques. On the other hand, measuring excess pore-water pressure is used in ascertaining layers and seams in fine-grained materials.
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