Investigation of frost/pipe heave associated with large-diameter chilled gas pipeline operation using a small-scale laboratory model

This paper provides a brief outline of the design, construction and instrumentation of a smallscale laboratory model of a chilled gas pipeline, together with initial findings. The small-scale model was designed to investigate the relationships between the growth of the frozen annulus, frost/pipe heave, ground movement and ground cracking under controlled conditions. Thus laboratory modelling eliminated the spatial variability of soil characteristics, water table, depth of burial of the pipe, together with the effect of ambient temperatures. The model consisted of a 90 mm O.D. steel pipe passing through an insulated perspex box filled with a known frost susceptible soil. A coolant was passed through the pipe and monitoring of the thermal and hydraulic regimes together with pipe and ground surface movements were undertaken.