Definition - What does Mixed Face mean?
Mixed face is defined as a type of soil condition where two or more different soil types are encountered in the path of the directional drilling machine. This can prove to be a difficult task for trenchless methods as the tools required for drilling are largely dependent on the kind of soil that the drilling machine will encounter. It is therefore essential to undertake testing of soil bores in regular intervals to determine the kind of subsurface conditions that will be encountered.
Trenchlesspedia explains Mixed Face
Mixed face can present as many different types of geology such as boulders, cobbles, hard clay, glacial till, soft clay and dry alluvium among others. Various soil conditions require different kinds of cutting tools. If these soil conditions are not known prior to commencement of a project, it can lead to a collapse of the bore hole, damage to the drill head, or cutting head, and ultimately, failure of the project. Studying the geology of an area including surface conditions, subsurface soil types, and the groundwater table helps to plan the most feasible route and can help in avoiding patches of hard rock or soft clay that can prove to be very challenging for the directional boring project.