What is the use of Thrust Anchor/ Thrust Block in pipeline?

A conventional anchor block is a reinforced concrete block which is cast around a straight piece of pipe, and which is designed to restrain the pipe against longitudinal movement. The longitudinal thrust from the pipe is transferred into the anchor block via a puddle flange clamped onto the pipe (for DICL pipes) or via a thrust collar welded to the pipe (for MSCL pipes).

To prevent the damge to the pipe which is caused by the unsupported movement