What is a Piezocone Penetrometer Test?
The piezocone penetration test (CPTu) is a in-situ testing method used to determine the geotechnical engineering properties of soils and assessing subsurface stratigraphy, relative density, strength and equilibrium groundwater pressures. The test is a special type of Cone Penetration Test (CPT) which allows additional measurement of excess pore pressure generated during the penetration. The "u" in CPTu represents the porewater pressure. Due to its efficiency and precision, the CPTu is becoming one of the commonly used in-situ testing methods in geotechnical investigation worldwide.

What Makes a CPTu Test Better Than a CPT Test?​
​Compared to static CPT, the electrical CPTu has been significantly improved in terms of precision and acquired data. The data can be continuously acquired at much smaller intervals compared to mechanical CPT.

CPTu can be also used to carry out pore pressure dissipation test. A dissipation test can be performed at any depth by measuring the rate of excess pore water dissipation of excess pore pressure to reach a certain percentage of equilibrium value representing the hydrostatic water pressure at that depth. The test provides useful information about the porewater pressure dissipation of the soil and its potential for liquefaction.
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CPT/CPTu static tests are used for the precise recognition of the characteristics of the subsoil. They are executed to identify sequence and depth of occurrence of the geological layers, to determine soil-water conditions and physical and mechanical properties of the individual layer. Based on the obtained results, the foundation of the structure can be designed optimally, i.e. optimum length of piles and their load-bearing capacity, and dimensions of shallow foundations.