Journal of University of Duhok, Vol.32, No.2 (Pure and Eng. Sciences), Pp 523-534, 3232 (Special Issue) 3 rd international conference on recent innovations in engineering (ICRIE) Duhok, September 9-10-2020 Younis.ali@univsul.edu.iq 1 Corresponding author: Engineering College, Sulaimani University, Kurdistan Region, Iraq 523 DEFORMABILITY AND SHEAR STRENGTH PARAMETERS OF THE FOUNDATION OF A PROJECT ON TANJERO FORMATION IN IRAQ USING RMR AND GSI YOUNIS M. ALI ALSHKANE ,1 College of Engineering, University of Sulaimani, Kurdistan Region-Iraq (Accepted for Publication: December 8, 2020) ABSTRACT Determination of the shear strength and deformability parameters of weak rocks are very significant in order to design the foundation of buildings on it economically and safely. Tanjero formation consists of an alternation of sandstone and silty marlstone and it is considered as a weak rock layer which makes it difficult to determine precisely its bearing capacity. Understanding the behavior of this formation under loading is one of the most challenges in geotechnical engineering. The formation underlies most of the areas in Sulaimani city and significant projects such as Shari Daik and Barzayakni Sulaimni projects in Sulaimani city in Iraq. In this paper, the mentioned parameters of this formation were predicted and recommended for the foundation of a multi-story building at Shari Daik project in Sulaimani city in Iraq based on Rock Mass Rating (RMR) and Geological Strength Index (GSI) rock systems. KEYWORDS: Weak rock; GSI; Rock Mass; RMR; Shear strength parameters and Deformability. 1. INTRODUCTION nderstanding the engineering properties and bearing capacity of weak rocks is a challenge to geotechnical engineers and geologists (Ahmed and Jamin, 2018; Ioanna et al., 2009). Weak rocks often form a great portion of the shallow stratums all over the world especially in Sulaimani region in Iraq. Since the foundation of many construction projects are built on weak rock, it is crucial to investigate the geotechnical properties of weak rocks such as Tanjero formation in Iraq. Tanjero formation consists of alternation of thin layers of sandstone and silty marlstone (Buday, 1980). The rock formation at Shari Daik project at the foundation of building A10 was chosen as a case study which is located in Sulaimani city, especially at the Dabashan District opposite the Chavi land park. Figure 1 shows the site plan of the project. The project is a multi-story building (23 stories) and is constructed as a reinforced concrete frame building. This paper includes the results of geotechnical investigation for the foundation of the project so as to estimate the shear strength parameters and modulus of deformation using both rock classification systems: Rock Mass Rating (RMR) by Bieniawski, (1989) and Geological Strength Index (GSI) by Hoek (2002). The field work includes the rock mass investigation by taking rock cores from the foundation of the project and field study for measuring the orientation of joint sets of the rock mass under the building. In addition, it includes the results of laboratory testing, subsurface exploration, assessment of test results and Conclusions. U