What is a tapered test?

The

cone test, usually called a cone penetration test (CPT), is the type of soil test used to collect different types of data. CPT collects data at regular intervals as it penetrates down the attic. The data collected from the cone test can be used to design bulk foundations and to evaluate the seismic classification of land.

The cone test is thus named because the device used to push into the soil consists of a cylindrical metal rod with a conical tip. Other parts include moving friction sleeves, filter element for measuring porous pressure and sensors for measuring various forces acting on the rod. The whole assembly, which goes to the soil, is known as a penetometer cone or piezoconnetometer. Petrometers can be mechanical or electrical and different cone diameters can be used - common sizes include 0.55 inches (about 1.4 cm), 1.42 inches (about 3.6 cm) and 1.73 inches (about 4.4 cm).

To perform measurement using a cone penetrometer, a CPT set is necessary. The set is a truck specifically equippedto carry out conical tests. In the center of the flat bed of the truck, the hydraulic ram is mounted to push Petrometer down the attic. The car also contains instrumentation that records strength at the tip of the cone, friction force for friction, pore pressure and in some cases measuring the speed of shear wool. The computer in the set records all data collected during the test.

For the conical test, the hydraulic ram Petrometer pushes through the soil at constant speed, usually 0.79 inches per second (about 2 cm per second). The desired measurements are carried out for the same steps between 0.20 and 1.97 inches (about 0.5 and 5 cm). The pernetometer runs deeper into the soil of a long part of the rod about 3.28 feet (1 meter). Once the Petrometer is removed, the hole is filled as dictated by local regulations.

Further equipment is needed to perform a seismic evaluation using a cone test. Seismic tests require a special type of petrometer called seismic conical penetometer (SCPT) that measures speedShear waves. Settings for the seismic test also include a board that contains a triggering device. Testing staff hits a plate with hammers of the sled and generates seismic waves. The computer used to collect data can act as an oscilloscope, a device that collects shear waves.