Is thrust wall an essential element in pipe jacking? Can it be omitted if there is insufficient depth for constructing normal thrust wall?

Thrust wall is an essential element in pipe jacking and it provides the reaction against the pipe jacking operation. In poor ground, consideration may be given to using piling or other methods to increase the stiffness of thrust wall. When there is insufficient depth to construct thrust wall (e.g. jacking through an embankment), a structure has still be constructed to provide the reaction to pipe jacking. In this case, the resistance to horizontal jacking loads is resisted by piles, ground anchors or other methods to reinforce the structure.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.