Most sheet pile retaining walls need supplementary support at the top, in addition to embedment in the soil. Temporary cofferdams generally use walers and struts for crossbracing inside the excavation. Permanent or large retaining walls are often tied back to an anchor wall installed a certain distance behing the wall.
Other anchor systems, like injection anchors or anchor piles can also be used.
The following drawing shows a typical horizontal tie-rod connection for sheet pile walls. The following components can be seen: