Geotechnical Characterization and Applications of Riyadh Metro Tunnel Boring Machine Excavated Material (TBMEM)

Abstract

The Riyadh city is witnessing one of the most significant infrastructure projects in its history. The 22.5 billion dollars and 180 km in total length Riyadh Metro project will be constructed using different tunnelling methods: 10 m diameter tunnel boring machine (TBM), cut and cover, and new Austrian tunnelling method (NATM). About 35 km will be constructed using 10 m diameter TBMs, which will produce approximately 2.8 million cubic meters of TBM excavated material (TBMEM). Transferring such an amount of material will cause a severe impact on the environment and traffic as it required many trucks to transport the material to a remote site. The comprehensive geotechnical characterization profile of the material was prepared in order to understand the performance of the material and identify the areas in which the material can be utilized. In addition, this paper will explore the potential of using TBMEM after being treated and mix with clean sand to enhance its geotechnical characteristics. Several potential areas to utilize the TBMEM will be presented. Furthermore, the project will investigate the applicability of TBMEM to be used as backfill material and to what extent the treatment should go to achieve a mixture that meets the standard requirements.