Publication Abstract

Proceedings-DFI-India 2016: 6th Conference on Deep Foundation Technologies for Infrastructure Development in India, (DFI)

Basement Excavation: Cost Effective Retention System for a Multi Storeyed Structure
Madan Kumar Annam, and Hari Krishna Y., Geotechnical Solutions, Keller, India

Basement construction is one of the challenging geotechnical concerns in the urban environment. Several types of retention systems are practiced to support the earth which is suitable for restricted access, rapid mobilization, fast excavation and cost-effective designs. A thorough understanding of geotechnical engineering as well as the structural mechanics is important for the earth retention systems. This paper discusses a project with various types of foundation solutions including monitoring of deflections during excavation stage of a retention system. A multi storeyed residential building (3B+Stilt+18F) in Chennai having structure foot print area of 1500 mē has to be constructed on large diameter pile foundations and also to support the proposed basement excavation. Ground water table was encountered at about 6m below the existing ground level (EGL). In order to support heavy structural loads, large diameter bored cast-in-situ piles were chosen and installed. Further, complete retention system was economically designed and built, which includes installation of Contiguous Bored Piles (CBP) in combination of vertical grout columns behind CBP wall to seal the gap between the CB Piles, installation of inclined ground anchors, construction of capping beam, stressing and locking of installed ground anchors. A detailed monitoring program was in place and continuous monitoring of wall deflections is being measured at the time of publishing this paper. This paper describes the design and construction aspects adopted for foundation and retention system including the monitoring results during excavation stage of the project.

 article #2219; publication #1020 (INDIA-2016)