(a) Picture of the experimental set-up, (b) close-up picture of the key component, (c) schematic diagram of the set-up and (d) cross-section sketch of the prototype of the device. 1– device, 2 – hand pump, 3 – external pressure sensor, 4 – data logging system, 5 – piezocone, 6 – oil bath for saturation, 7 – annular chamber, 8 – piezocone filter, 9 – impermeable membrane