Be careful with your interpretation of the phrase "virtual anchor" or "virtual anchor length". This is not a distance to an anchor. It is instead a buried length of pipe, long enough so that the axial friction along this length prevents any load or displacement at one end from translating to the other end. A straight run with no branches longer than this length need not be modeled beyond this length.

But don't add an anchor in CAESAR II (CAESAR II). As Sun Wee suggests, just run it way out there and let CAESAR II "bury" it.

CAESAR II prints out the calculated Virtual Anchor Length (VAL) in the buried modeler. But this length assumes the soil holds the pipe fixed until the friction load is exceeded. Our soil model uses a bilinear stiffness to model these friction effects so some "slippage" must occur to build up the friction force along the length. (This slippage is the x in f=kx.) This requires longer runs to set up the "anchor". I run lengths much longer than the calculated value.