Thanks DRC1 and PEinc!
Your replies are great helps to me.
The trenching is through a downtown street with very close adjacent buildings. Therefore I am so concerned about the affect of dewatering.
I used to deal with excavation for high-rise building construction and this is the first time for...
To PEinc:
Can I use soldier pile and lagging to support a 4 m deep trench excavation? The soil is generally firm to stiff silty clay and compact silty sand fill with water table at 2-3 m. This is the first time I am dealing with a sanitary sewer excavation. If yes, what kind of material and what...