Triaxial shear testing is one of the most important laboratory procedures in geotechnical engineering, yet it's rarely explained well outside of university lecture halls. This video from Civil Test & Build walks through the three standard variants of the triaxial test: Unconsolidated Undrained (UU), Consolidated Undrained (CU), and Consolidated Drained (CD).

Each test type simulates different field drainage conditions, and choosing the right one matters enormously for real-world design. A UU test models rapid loading on saturated clay — think of an emergency embankment built on soft ground. A CD test represents long-term stability where pore pressures have fully dissipated. CU sits in between, giving you both total and effective stress parameters. Understanding when to apply each test is just as critical as understanding the mechanics behind them.

The video covers the practical setup and procedure of each test type, making it a useful reference for civil engineering students encountering soil mechanics lab work for the first time, or for early-career engineers who need a refresher on how shear strength parameters like cohesion and friction angle are actually measured. The channel focuses on combining test procedures with conceptual explanation, which gives it more depth than a typical exam-prep clip.