Patrick Leevers, Christos Argyrakis
Papers # 2010 Vancouver
There is renewed interest in the correlation between critical pressures from lab-scale (S4) and full-scale RCP tests. The standard, supposedly material-independent correlation factor does provide a lower bound for data from many PE grades, but for some grades it is overconservative and for PA12 its applicability has been questioned. To investigate this issue and others, we return to the fracture mechanics modelling of both tests. Previous models have tended to be oversimpliﬁed, overcomplicated and/or computationally opaque. We present a ﬂexible, analytically basic model which accounts for all major inﬂuences, including residual stress in the pipe wall and constraint from the surrounding backﬁll, using only a one-dimensional ﬁnite-diﬀerence method. Its results agree well with those from the earlier computational methods, while providing new insights on the role of processed-in residual stress, and of backﬁll under installed conditions.