Precise prediction of TBM performance is one of the most crucial issues in mechanized tunneling projects. The main objective of this study is to estimate the TBM rate of penetration by constructing a fuzzy inference system analysis. A database consisting of fabric index of Q rock mass classification system, rock material properties and machine characteristics and performance along the tunnel alignment was compiled. In order to verify the validity of the developed model, the predicted and field measured penetration rates were compared. Results picked out from this predictor model revealed that the model has a strong capability for estimation of TBM performance with a correlation coefficient of 81.5 %.
IntroductionPerformance prediction of tunnel boring machine is a complex and ambiguous engineering geological problem. This issue is crucial because a precise estimation of machine performance can considerably influence the cost and duration analysis during the planning stage of a mechanized tunneling project. A comprehensive review of the literature on the subject can be found in Khademi Hamidi et al. (2010b) and Farrokh et al. (2012). Among the most recently developed empirical prediction models, some ones have used intelligent systems such as artificial neural network (ANN), fuzzy logic and Neuro-Fuzzy hybrid techniques. Taking into consideration the nature of the problem, the main purpose of the present study is to develop a model by utilizing the fuzzy logic for predicting TBM performance. In order to achieve this aim, a database composed of rock mass properties including fabric indices of four rock mass classification and the angle between plane of weakness and tunnel axis, intact rock properties including uniaxial compressive strength, machine specifications including net thrust per cutter together with actual measured TBM rate of penetration(ROP) is compiled along the tunnel alignment. Alborz service tunnel situated in Tehran-Shomal freeway is chosen as a case study. The TehranShomal freeway project with about 120 km in length is a new freeway to connect the capital Tehran with the city of Chalus at the Caspian Sea in the north of Iran. The freeway alignment has more than 30 twin tunnels for double lanes. The Alborz tunnel is the longest of these with a length of 6,400 m at an altitude of 2,400 m. At this stage of the Alborz tunnel construction, an exploratory pilot tunnel is being driven in Kandovan region. This tunnel, 5.2 m in boring diameter, will be used for exploratory purposes prior to the start of the construction of main tunnels and will also serve as an emergency access and ventilation way and drainage during the life of the tunnels. Besides, it will be used for transportation and other services during the construction of main tunnels. Longitudinal profile of the geological sections is also shown in Fig. 185.1.