Determination of Safe Depth and Lateral Distance of Unsupported Excavation Near Mat Foundation in Cohesive Soils Using PLAXIS

Muhammad Hamza Khalid; Badee Alshameri

doi:10.6180/jase.202204_25(2).0011

Determination of Safe Depth and Lateral Distance of Unsupported Excavation Near Mat Foundation in Cohesive Soils Using PLAXIS

Muhammad Hamza Khalid¹ and Badee Alshameri This email address is being protected from spambots. You need JavaScript enabled to view it.²

¹Postgraduate student, Department of Geotechnical Engineering, NUST Institute of Civil Engineering (NICE), School of Civil & Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), Islamabad, Pakistan
²Assistant Professor, Head of Geotechnical Engineering Department, NUST Institute of Civil Engineering (NICE), School of Civil & Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), Islamabad, Pakistan

Received: April 6, 2021
Accepted: June 18, 2021
Publication Date: September 9, 2021

Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.6180/jase.202204_25(2).0011

ABSTRACT

Deep excavations are essential to harbor urban needs of the present age. The excavation of pits for foundation construction in an already limited space in urban centers poses damage to the neighboring structures. In this study, two mat foundations on two different types of clay soils have been modeled in PLAXIS to determine the maximum depth of excavation and the minimum safe distance of the excavation pit from these mat foundations. The failure modes under consideration are excessive settlement, angle of distortion of the mat foundation, and pit face failure. A co-relation to determine the safe maximum depth of unsupported excavation pit and minimum horizontal distance from adjacent mat foundation is presented based on results from 195 models. The ratio of critical unsupported excavation depth and critical horizontal distance from an existing building first drops to 1:3 in all cases and then rises in a non-linear manner. The modes of failures at various stages have been highlighted based on 44 critical cases.

Keywords: PLAXIS, Mat Foundation; Cohesive Soils, Unsupported Excavation, Safe Depth, Safe Lateral Distance

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