Stabilizing Distressed Foundations of a School Building Adjoining a Deep Excavation

Two blocks of a school building located 2–10 m away from an 18 m deep excavation experienced settlement cracks. To stabilize the buildings, arrest any further distress, and protect the land adjoining the building from collapsing into the excavation, foundation strengthening was done. The steps taken include: (1) cement-grouting the soils on either side of the building wall to control the movement of soil adjoining the foundations, (2) installing a row of 300 mm diameter 8 m long auger piles at 400 mm spacing to create a confinement to the soils adjoining the foundations, and (3) installing a row of 500 mm diameter 18 m long bored RCC cast-in situ piles to protect the soils adjoining the excavation. The whole scheme was designed in such a way that even if the neighbor delays the basement wall construction, the school facilities shall remain safe from a geotechnical point of view.