Influence of Interaction between Tunnel Boring Machine and Ground on Thrust Force and Penetration Rates- Case study: Karaj-Tehran Water Conveyance Tunnel (Lot-2)

In mechanized tunneling with Tunnel Boring Machine (TBM), some parameters such as thrust force and penetration rate have an important role and they can be recorded and compared with values achieving from theoretical models. Karaj-Tehran water conveyance tunnel has been bored by hard rock TBM machine to supply the water for Tehran capital. This project is finished by two parts called Lot1 and Lot2. After investigating the tunnel face of each section in Lot2, ground characteristics and Geological Strength Index (GSI) were recorded respectively. After that, Uniaxial Compressive Strength (UCS) and Cerchar Abrasiveness Index (CAI) are measured by testing on rock samples. The boring thrust force of TBM was calculated by using above mentioned data and by using other common and applicable models. Beside, achieved data from TBM specially thrust force and penetration rate had been recorded at the same time. A comparison of measured and calculated thrust force by using TBM data showed that it is possible to analyze the differences between them at each section of tunnel. For this, some parameters such as database selection, sampling and tunnel face control have an important role on analysis. At the end, CSM model and tunnel face data are selected to evaluate the thrust force and their results are presented to describe the eight classes of rock mass.