The problem of deep excavation is not as simple as what one might see.

I teach all the possibilities of deep excavation failures in my lectures.

The possible causes of failures can be many, starting from:

1. Adoption of soil parameters
2. Drain undrained modeling of soil
3. Constitutive model adopted in evaluating the excavation process (example: a lot of peoples do not understand the drawbacks of Mohr Coulomb model)
4. The design of ground anchor. The ground anchors cannot be too. long, prestressing force must be properly evaluated.
5. The stiffness factor of the diaphragm wall.
6. The modelling of groundwater pressure, it is not as simple as phreatic groundwater alone. Effect of seepage must be considered. Also possibilities of existence artesian water pressure muat also be investigated.

Lastly, of course the construction process must also be carefully considered and properly executed as per design.

Many do not understand how to model deep excavation process in FEM even though they claim they are familiar with the software. They often do not understand the theoretical background of each modelling above.

My illustration is: Geotechnical FEM software is like a fighter plane. A commercial plane pilot may be able to fly a fighter plane, however, one wrong move the whole plane will crashed!!

My best regards to all engineers,

GTL, 220322-08:46WIB