Considering the growing expansion of underground construction in different regions of the world, tunnel contractors are dealing with more complex operations in longer projects. This is linked with excavation affronting different geological profiles. Therefore, the use of tunnel boring machines (TBMs) is growing more and more, and with it the necessity of different chemical products to support their operation from foams for the conditioning of the
ground for EPBs (earth pressure balance), to different types of greases for critical or unique sealing applications.
If foam are to be used during excavation with a EPB TBM, then this document describes and defines a guideline to evaluate the choice of the different products in several specific tunnelling applications, considering performance, costs and environmental expectations. The document will additionally highlight the testing procedures for a screening of the technologies available in the market.