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In this project, we undertook the excavation of the entire garden footprint of a modern house within a gated community to create a versatile multi-purpose deep basement. This basement features luxurious amenities, including a swimming pool, library, cinema, and music room.  To ensure ground stability during excavation and construction, we implemented a contiguous piled wall system. This method involved closely spaced piles that functioned as effective retaining walls, preventing soil collapse and water ingress. Our design addressed both temporary and permanent conditions, maintaining the integrity of the site throughout the process.  To seamlessly integrate the new basement with the existing structure, we undertook a careful underpinning of the rear section of the house. This phased approach extended the foundation to the new basement depth, mitigating the risk of differential settlement and ensuring structural continuity between the new and existing foundations.  Given the highly shrinkable nature of the soil, we opted for a pile raft foundation for the basement slab. This design choice allows for an even distribution of heavy loads from the swimming pool and other amenities, providing a robust load-bearing platform. The pile raft foundation effectively addresses potential issues related to ground movement and soil heave, ensuring long-term structural stability. 

To protect the basement from groundwater penetration, we employed a multi-layered tanking system on the walls and floor. Additionally, we incorporated advanced drainage systems, including a perimeter channel and sump pumps, to effectively manage water ingress and maintain a dry environment.