Geotechnical Performance of a Supported Deep Excavation without Grouted Plug in Cairo, Egypt.
Volume Title: ICASGE2025
Paper ID : 1142-ICASGE-FULL
Authors
Ain Shams University
Abstract
Construction of a new development of two multi-story mixed-use towers, Nile Corniche Project, has been completed beside the River Nile in central Cairo. It comprises two thirty-floor towers above seven podium levels and four underground floors. A 15-m deep excavation, supported with diaphragm walls and two levels of grouted anchors, was needed over the entire area of the project (about 9400 m2) for the construction of the pile foundations and the underground floors. Due to time constrains, groundwater level within the excavation was lowered by about 11 m without implementing the usual grouted plug. An existing branch sewer tunnel about 2.5-m diameter is located parallel to the eastern boundary of the project site. It was, therefore, essential to assess the combined effect of the deep excavation and dewatering on this sewer tunnel.
Sophisticated Type-A analyses were performed using enhanced finite element analyses to model the construction phases of the underground structure of the project. Two selected geotechnical constitutive laws were used in the analyses (namely, Double Hardening Model and Small-Strain Double Hardening Model) to represent the upper and lower deformation limits. An extensive in-situ geotechnical monitoring program utilizing inclinometers, ground monitoring points, and piezometers was implemented for this project.
In this paper, comparison of the results of performed analyses with the compiled field measurements is presented. It was verified that the construction of the underground works had a negligible effect on the stability of the sewer tunnel and its structural safety.
Sophisticated Type-A analyses were performed using enhanced finite element analyses to model the construction phases of the underground structure of the project. Two selected geotechnical constitutive laws were used in the analyses (namely, Double Hardening Model and Small-Strain Double Hardening Model) to represent the upper and lower deformation limits. An extensive in-situ geotechnical monitoring program utilizing inclinometers, ground monitoring points, and piezometers was implemented for this project.
In this paper, comparison of the results of performed analyses with the compiled field measurements is presented. It was verified that the construction of the underground works had a negligible effect on the stability of the sewer tunnel and its structural safety.
Keywords
Supported Deep Excavation; Diaphragm Walls; Dewatering; Double Hardening Model; Small-Strain Double Hardening Model; In-Situ Geotechnical Monitoring
Subjects