Figure 1.
Panel a shows a schematic of a triaxial test system, where a helium pre charge vessel connects to an injection pump and pressure vessel, while a confining pressure pump applies pressure around a sample, and a back pressure pump and accumulator regulate flow, with a differential pressure transducer measuring pressure, and drains allowing fluid movement. Panel b shows laboratory equipment including pressure vessel, back pressure accumulator, injection pre charge vessel, gas inlet valve, hydraulic test circuit, drain valve, magnetic stirrer, and pumps, along with a sample wrapped in foil within a transparent membrane placed between platens, and secured by a lock ring.The experimental apparatus. (A) Schematic diagram showing the layout and key components of the apparatus. (B) Top left image shows the complete apparatus with control pumps, pressure vessel backpressure accumulator, magnetic stirrer, and differential transducer. The top right image is a close-up of the top of the pressure vessel and injection manifold. The bottom image shows the sample assembly and connecting tube-work to the pressure vessel end-closure