Vol.12 (2022) No. 6 ISSN: 2088-5334 Study of the Factors Affecting the Quality and Safety of Deep Excavations in Urban Areas of Casablanca-Settat Province-Morocco Boulaid Ghizlane a,* , Ouadif Latifa a , Bahi Lahcen a a Laboratory of Applied Geophysics, Geotechnics and Geology of Engineers and Environment, Mineral Engineering Department, Mohammadia School of Engineers, Mohammed V University, Ibn Sina Avenue, Rabat, 765, Morocco Corresponding author: * ghizlane_boulaid@um5.ac.ma Abstract— Understanding the project environment is essential in managing the works and controlling the risks associated with deep excavations in urban areas. The study was carried out on 33 risks related to the project site (SR) and the company (CR). The projects concerned are located in the Casablanca region. A structured survey questionnaire was sent to 100 project managers, researchers, and construction management experts to attract relevant data, which resulted in a relatively high response rate of 54%. This paper applies the principal component analysis (PCA) method to reduce the original data variables and identify risk factors associated with deep excavations. Spearman rank correlation tests show a good consensus among respondents to corroborate the results further. The PCA results in four principal factors (SR) accounting for 68% of the variance explained. Site geology, geotechnics, and hydrogeology account for 32% of the environmental and social impacts of excavation (17%), natural hazards (10%), and proximity to existing structures (8%). Moreover, four main factors (CR) explain about 72% of all the factors analyzed; non-security of the works (32%), non-quality of project staff (18%), project cost overrun (14%), and non-quality of excavation works (9%). These results are useful for critical thinking in planning excavation projects in urban areas. This study provides the urban development community with valuable information to reassess risk factors and realign project management strategies to ensure the quality and safety of deep excavations. Keywords— Deep excavations; risk factor; urban areas; principal component analysis (PCA); spearman rank; project site. Manuscript received 13 Sep. 2021; revised 8 Oct. 2021; accepted 29 May. 2022. Date of publication 31 Dec. 2022. IJASEIT is licensed under a Creative Commons Attribution-Share Alike 4.0 International License. I. INTRODUCTION Cities in Morocco have grown with very rapid urbanization. In addition, the construction of high-rise buildings, subways, and tunnels that necessitate deep excavations can present considerable potential risks. According to the Moroccan Ministry of Employment, construction is the sector most affected by work accidents and records the highest mortality; compared to other sectors, accidents on construction sites are frequent in Morocco. In March 2018, the fall of a crane on a construction site in Sidi Moumen (Casablanca) caused two deaths. A similar accident in April 2018 on Al Fourate Street (Casablanca) impacted neighboring residences. At the beginning of October 2018, the walls of a construction site collapsed, threatening in extremis the surrounding buildings. In July 2014, a collapse of three buildings in Casablanca caused eight deaths. In June 2016, 2 children were injured in the partial collapse of a building in the Garage Allal neighborhood due to nearby deep excavations, and in October 2018, a collapse of part of the walls of a building site in the middle of Hay Riad in Rabat caused by the subsidence of the ground, which involved a landslide at the level of the basement walls [1]. According to the Moroccan insurance and social security control authority (ACAPS) statistics, an average of 40,000 work accidents are recorded annually in the construction industry, and 2,000 deaths are declared [2]. Deep excavations in urban sites present risks [3] due to the surrounding structures [3], [4], underground networks, old buildings, nearby roads, and the said risks such as cracking or collapse of nearby buildings [3], [4], degradation of roads and underground networks [5]–[8], soil compaction, landslides, and soil subsidence [9], [10]. Multivariate statistical methods have also been used to identify the major risks that menace an urban excavation's stability [11]. Determining and evaluating the different risks are necessary for good management and planning of excavation works to avoid human and material damage. The objective of this study is to use multivariate statistical techniques such as Principal Component Analysis (PCA) [12] to evaluate the factors influencing the stability of the works. 2174