Controlled Hydraulic Gradient Soil Test Equipment

Controlled hydraulic gradient means the user can set a maximum pressure gradient across the sample.  In triaxial permeability testing this coule be the difference (i.e. the gradient) between the applied back pressure at the top of the sample and the measured pore pressure at the base of the sample, or in triaxial shearing it could be related to the excess pore pressure generated during a shearing test. If the user defined value is exceeded then the test will be paused until the sample equilibrates enough to bring the difference back to within the stated pressure before continuing.  Effectively by having control on the hydraulic gradient the test will not run too fast for the permeability of the soil. 

The following soil test equipment can perform the Controlled Hydraulic Gradient soil test:-