Cone penetrometer test is also referred to as cone penetration test, often abbreviated as CPT. This is a method that is used in the determination of geotechnical engineering properties of soils and the delineation of soil stratigraphy. The invention of CPT happened in the 1950s in Delft. The invention happened in the Dutch Lab for Soil Mechanics when scientists were investigating soft soils. Here are facts regarding cone penetrometer test for soil.
Sometimes, the process is referred to as Dutch cone test because it originated from the Netherlands. This process has been accepted all over the world despite it having been invented and developed in Europe. It is among the best methods of investigating soils. Projects that deal with ground compaction mostly apply this method. Currently, various types of mechanical and electrical cone penetrometers are available. However, the electric cone is the most common.
CPT utilizes a conical tip that is normally pushed into the earth at a rate of 2 cm per minute. This conical tip has a diameter of 35.7 millimeter and an apex angle of 60 degrees. A steel rod connects to the conical tip and has a similar diameter as the conical tip. The pinecone is normally pushed into the earth at a rate that varies between 1.5 and 2.5 centimeters per second.
When the pinecone is being pushed deeper into the soil, there is resistance at its tip and also along its shaft. This friction is measured. Friction sleeve is the portion that is located just after the pinecone, and it is subjected to friction. In most cases, the friction sleeve is 15,000 millimeters in diameter.
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.
It is possible to include other kinds of sensors in the CPT so that it can measure other aspects of the ground being worked on. For instance, vibration sensors can be included to help in determining vibration velocity and acceleration. CPT is a very standardized test, with results not being operator-dependent like it is with SPT. The fact that the results are not operator dependent makes them reproducible.
Sleeve friction and pinecone resistance which are measured by CPT are used to gauge the friction ratio (FR). Difference in lateral earth pressure in the ground is indicated by the sleeve friction. Therefore, the state of stress in relation to ground compaction can be determined using the sleeve friction. Overburdened pressure interferes with the measurement of sleeve and pinecone friction to a greater extent.
CPT aims to obtain information concerning ground stratification and variation in soil properties both in vertical and horizontal directions. The friction ratio is an indicator of soil type and provides useful information in the evaluation of alternative compaction methods. Measurements of excess pore water pressure are used in detecting seams and layers of fine-grained materials.
Sometimes, the process is referred to as Dutch cone test because it originated from the Netherlands. This process has been accepted all over the world despite it having been invented and developed in Europe. It is among the best methods of investigating soils. Projects that deal with ground compaction mostly apply this method. Currently, various types of mechanical and electrical cone penetrometers are available. However, the electric cone is the most common.
CPT utilizes a conical tip that is normally pushed into the earth at a rate of 2 cm per minute. This conical tip has a diameter of 35.7 millimeter and an apex angle of 60 degrees. A steel rod connects to the conical tip and has a similar diameter as the conical tip. The pinecone is normally pushed into the earth at a rate that varies between 1.5 and 2.5 centimeters per second.
When the pinecone is being pushed deeper into the soil, there is resistance at its tip and also along its shaft. This friction is measured. Friction sleeve is the portion that is located just after the pinecone, and it is subjected to friction. In most cases, the friction sleeve is 15,000 millimeters in diameter.
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.
It is possible to include other kinds of sensors in the CPT so that it can measure other aspects of the ground being worked on. For instance, vibration sensors can be included to help in determining vibration velocity and acceleration. CPT is a very standardized test, with results not being operator-dependent like it is with SPT. The fact that the results are not operator dependent makes them reproducible.
Sleeve friction and pinecone resistance which are measured by CPT are used to gauge the friction ratio (FR). Difference in lateral earth pressure in the ground is indicated by the sleeve friction. Therefore, the state of stress in relation to ground compaction can be determined using the sleeve friction. Overburdened pressure interferes with the measurement of sleeve and pinecone friction to a greater extent.
CPT aims to obtain information concerning ground stratification and variation in soil properties both in vertical and horizontal directions. The friction ratio is an indicator of soil type and provides useful information in the evaluation of alternative compaction methods. Measurements of excess pore water pressure are used in detecting seams and layers of fine-grained materials.
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