Effect of Soil Conditioning on the EPB-TBM Excavation Performance: A Case Study of Dudullu-Bostanci Metro Project, Turkey
The use of underground space for transportation, energy requirement, sanitation and wastewater management is continuously increasing in urban areas. Mechanical excavation of this underground space with Earth Balance Pressure Tunnel Boring Machine (EPBTBM) is one of the most preferred method beneath intensive urban areas. A good soil conditioning can reduce the surface settlement and create a good counter face pressure. This study aimed to investigate the effect of soil conditioning on the EPB-TBM excavation performance of Dudullu-Bostanci metro project in Turkey. During field visits, different soil samples were collected to define some important physical properties. This investigation indicated that the cutterhead torque increases with increasing consistency index. In addition, the specific energy has a direct relationship with the plastic limit index and it increases with the increasing PI. However, in order to better insight on the relationship between soil characteristics and the TBM performance parameters, it is highly recommended to use different soil types and TBM data to reach an overall TBM performance prediction based on the soil characteristics.