Full Displacement Cone Pressuremeter
From Cone Penetrometers
The full displacement pressuremeter, or pressuremeter cone, is a device designed to apply a uniform pressure to the walls of the hole by means of a flexible expanding membrane. This in-situ test measures both soil strength and stiffness parameters at strain levels as low as 0.01%. The pressuremeter is comprised of a pair of calibrated strain arms housed within an inflatable rubber membrane, cased within an expandable Chinese lantern for improved durability. The device is mounted to the CPT apparatus and pushed to depth. With the test paused, the membrane is inflated using controlled stress and strain rates.
During data acquisition two unload-reload loops are performed to determine stiffness parameters (shear modulus) to 0.01% strain levels and the undrained shear strength of clays (based on Houlsby & Withers, 1998).
The cone pressuremeter is an economic alternative to conventional self-boring and Menard type pressuremeter testing. The test can be carried out in a wide range of material types from soft to stiff clays and loose to medium dense sands.