How do you check the overall stability?
Pile foundations provide the wall stability directly by the forces taken by the piles. Unlike walls founded on soil, which transfer compression-only forces to the foundation, piles usually have a tension capacity. Therefore the applied overturning moment can be resisted by a couple of forces on the piles, one in tension and one in compression.
Likewise, the applied sliding force will be resisted by the lateral capacity of the vertical piles. When more lateral capacity is required, some piles may be battered so that the horizontal component of the axial load can be used to resist the sliding force.
Unlike walls on soil, the bearing capacity of the pile foundation can be increased by adding more piles, either vertical or batter, per the soils report recommendations. The number and location of piles is very important to calculate the pile forces. Each pile axial load must be smaller than the axial capacity, and the sliding force must be smaller than the horizontal capacity of the pile group.
As an example, the picture below shows the ASDIP RETAIN pile calculations. Note that the controlling load combination is based on service loads.