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.
Friction is recorded by the use of transducers which are attached to the electric CPT. In cases where the CPT probe is integrated with pore-water pressure sensors, it is normally called a CPTU. One should ensure that the filter ring within the pore-water element is saturated with water completely. If the element is not completely saturated, it will lead to erroneous results being recorded by the piezo- transducer.
CPTs can also be used to determine other elements of the soil by having different types of sensors incorporated. It is possible for CPTs to measure the velocity and acceleration of vibration when they have vibration sensors. Results from an SPT usually depend on the operator. This is not the case with CPT since the process is highly standardized. As such, CPTs are reproducible because the results from them are independent of the operator.
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.
Friction is recorded by the use of transducers which are attached to the electric CPT. In cases where the CPT probe is integrated with pore-water pressure sensors, it is normally called a CPTU. One should ensure that the filter ring within the pore-water element is saturated with water completely. If the element is not completely saturated, it will lead to erroneous results being recorded by the piezo- transducer.
CPTs can also be used to determine other elements of the soil by having different types of sensors incorporated. It is possible for CPTs to measure the velocity and acceleration of vibration when they have vibration sensors. Results from an SPT usually depend on the operator. This is not the case with CPT since the process is highly standardized. As such, CPTs are reproducible because the results from them are independent of the operator.
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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