Swelling of clay develops significant stresses on pipe and its effect is even magnified by the use of lubricant. How can swelling inhibitors help to resolve this problem?

Lubricants are introduced in pipe jacking to reduce the jacking loads. However, for pipe jacking in clay the swelling of clay is accelerated by water-based lubricant as the free water in the lubricant is readily absorbed
by clay. To address the problem, swelling inhibitors are added to lubricants which enhance a reduction of free swelling for clays. In essence, the ability of swelling inhibitors to reduce free swelling of clay is achieved by the alternation of clay properties and formation of barrier on cavity surface.

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.