My company has been engaged in this project in NYC, we are going to prepare SOE for exist. building vertical and horizontal extension. They are deepening the existing cellar - new foundation will be 4-5' lower than exist. The ground water table is around 11' below the sidewalk elevation which means we will be around 5' under ground water table..There are 2 adjacent masonry buildings..all buildings around 100 years old. I've done recently SOE for the same scenario at nearby property where I did sheet piles and now my boss is trying to "Design" a custom made hydraulic press to press sheet piles in - but as you can imagine, I am not sure if that's gonna work so I don't want to rely on this. That's why I would like to look for an alternative. Can I dewater the site without causing any damages to the adjacent properties and then do a typical underpinning ? Or is it too risky? I know secant piles is the option but it might be too expensive.Any reference materials would be very helpful.Thank you for any advice.