In this article at first NTH and CSM utilization factor prediction models as topics of the empirical and the theory-empirical models are reviewed. Then with notice to structure of the data bank that is used for prediction of utilization, effective parameters on utilization are introduced. With use of two and multi variable statistical analysis some relations are presented for prediction of utilization and on results obtained from theses relations are discussed. In flow with use of Neuro Network the most suitable Network for prediction of utilization is determined and ability of this network in comparison with multi variable statistical analysis and real value of utilization factor is investigated. Prediction of utilization for Gavoshan Tunnel's TBM with Neuro Network is discussed in the latest parts of article.

Summary: The numerical study of airflow has mainly concentrated on underground mines and road tunnels. Ventilation during the construction of long tunnels, especially the ventilation of TBMs, has received less attention. This paper aims to study airflow pattern in TBMs with regard to safety and as such reduce dead zones area. The results show that the airflow pattern of a TBM ventilation system, which can help to design an effective ventilation system for the TBMs. Introduction: The Tunnel Boring Machines (TBMs) has revolutionized the tunneling industry to create underground space safer, healthier and more economical. Ventilation is one of the main components of mechanized tunneling. The airflow quality and the related mass flow rate in the ventilation system should be sufficient to dilute gases and remove the dust inside the tunnel. Since most of TBM crews stay and work in the mainframe area, ventilation of this zone is very important. Methodology and Approaches: In this study, we modeled the TBM ventilation system using CFD method to understand airflow behavior in TBM. Numerical solution of the governing equations and boundary conditions are performed by utilizing the commercial CFD code Ansys CFX 18. 1. Tests of mesh-independence were conducted based on four different meshing creations. To define the boundary conditions, airflow velocity sampling was performed using multi-point sampling method in the ductwork outlet. To complete the discretization of the advection term, the high-resolution scheme was computed. Root Means Square (RMS) < was considered as the convergence criterion of mass and momentum equations. Results and Conclusions: The results show that there is not enough air flow in 89. 2% of TBM space in its current state. There are many dead zones from control cabin to the end of mainframe. The main direction of the back airflow moves along the segment feeder and increasing air mass flow has no effect in decreasing dead zones area. The results from the study present show that by increasing the air mass flow rate by 60% the volume of the dead zones in TBM is decreased by 13. 42% and has no effective decrease dead zone in the personnel breathing zone. The results from the present study clearly indicate that maximum mass flow capacity of jet fans is not possible to reduce dead zones that will only increase energy costs.

The overall purpose of this study is to use probabilistic methods for the estimation of the advanced rate of full-face tunnel boring machines. To collect appropriate input parameters, Monte Carlo Simulation was utilized. Then, the calculation phase was conducted applying established models on input data and probability density functions of output data were obtained. The results show that the average advance rates calculated by QTBM and CSM models were closer to the average value of the actual advance rates. In addition, using probabilistic methods in combination with TBM prediction models helps to estimate the range of advance rates more confidently.

In this article at first some models of penetration rate prediction were reviewed then a Neuro Network was created for prediction of penetration rate. The Neuro Network inputs are UCS, RQD, normal force on disc cutter, diameter of disc cutter and quartz content. With elimination of quartz content and RQD from input parameters, the response of Neuro Network was investigated. Neuro Network response Compared with Garaham Model, and ability of Neuro Network in penetration rate prediction and prediction penetration rate of Gavoshan Tunnel's TBM were discussed in the latest part of article.

The excavation and construction of underground stations are essential elements of modern urban infrastructure. This research article delves into the critical aspect of station construction within underground transportation systems, focusing specifically on stabilizing entrance walls of a metro station, particularly for Tunnel Boring Machine (TBM) entrances. The study conducts a comparative analysis between two support systems: the plastic concrete piles method and its combination with soil nailing, evaluating their efficacy in the context of TBM entrances. Employing both 2D and 3D Finite Element Modelling (FEM), the research investigates various soil constitutive models, including the Hardening Soil and Hardening Soil with Small Strain models. The findings emphasize the combined approach of utilizing plastic concrete piles with soil nailing as being more advantageous, demonstrating superior displacement control. Additionally, the comparison of modelling approaches indicates that the utilization of 3D modelling with the Hardening Soil with Small Strain model is recommended for numerical analysis of deep excavations near sensitive properties due to its ability to predict realistic ground movement distributions.

Summary In this paper, a novel method based on a semi-ring support has been developed and proposed to facilitate TBM passing the station and restarting the excavation. The results show that the proposed method can be safely used. Introduction Crossing of station is one of the most challenging problems in construction of metro lines. Given the difficulties and problems of using the push frame in the TBM passing station and restarting excavation, this study presents a method based on the use of segmental rings that has been developed for use in underground stations. Methodology and Approaches In this method, in order to create a support for applying the force of TBM thrust, a different pattern of the installation of the incomplete rings has been used so that in addition to utilizing the advantages of using the semi-ring support in such a way that any complete ring is not installed in the space of the station. The proposed pattern is such that three floor segments are used to a distance of about 5 to 6 rings to the end of station; so that TBM will pass through the length of the station. Thereafter, in a few rings, the number of segments increases to 4 and then 5 segments per ring until the cutter head reaches the end of the station. From this stage, the tunnel excavation continues with the installation of the semi-rings of 5 and 6 segments, until the boring machine is completely inserted into the tunnel so that the first complete ring is installed at the beginning of the tunnel. Results and Conclusions The results show that excavation can begin using the 5 and 6 segments, but semi-ring of 6 segments is somewhat superior to 5 segments. The proposed model has been evaluated at some stations of line 6 of Tehran metro and the results show that, in addition to the effectiveness of this method, any over-the-counter deviation has not occurred. Therefore, the proposed method can be safely used.

U7 station as a backup and service center has been situated in the middle of northern-southern Tehran’s metro line 7 project, in which is being excavated using an Earth Pressure Balance (EPB) machine. In this paper, the most appropriate stabilization method for the exterior portal has been nominated, and afterward the influence of tunnel excavation with TBM upon the stability of the above-mentioned portal has also been explored in the excavating procedure onset using numerical method. As a result, soil substitution with plastic concrete which can also be categorized as one of the ground improvement methods has been selected to mitigate difficulties more effectively. In addition, optimized length of plastic concrete used to minimize tunnel face displacement and to restrict prospect instability has numerically been yielded.Introduction: In today’s world, development in infrastructure facility systems such as subways is in the public eyes more than ever. These underground openings are situated in urban and/or residential areas equated with soft soils and alluviums. Furthermore, providing a stable span for the TBM operations in station would be of great importance to avoid encountering any potential hazard like settlement, economic limitation, and even human casualties. Consequently, in EPB mechanized tunneling, fairly proper stabilization method of any station portals is found to be influential.Methodology and Approaches: In this study, the FLAC3D software has been utilized to carry out 3D numerical modeling to investigate the influence of plastic concrete on the face stability. In addition, the Mohr-Coulomb criterion has been taken into account for geo-mechanical behavior of soil material surrounding the tunnel. Since EPB machine is not capable of producing fairly enough pressure against the tunnel face to maintain stability at the beginning of the excavation up to 1.5 meter, hence plastic concrete length required for face stability is found to be 1.5 meter. Accordingly, five plastic concrete of 2, 3, 4, 5, and 10 meter long has been inserted to a numerical model. Finally, optimized length and lateral expansion of plastic concrete have been designed generally based on result driven from numerical analysis such as tunnel crown and face displacement, raptured zones around the tunnel face and wall. Results and Conclusions: Three dimensional modeling has revealed that required length to fulfill tunnel face stability is 4 meter long with respect to face displacement magnitudes and also raptured zones. Lateral expansion of plastic concrete, however, should not exceed 1 meter. Results have demonstrated that plastic concrete plays a significant role in preventing tunnel crown from enormous displacement.

In mechanized tunneling, TBM performance prediction is vital to estimate the time and cost of the project.Therefore, calculating the performance parameters is so important. The utilization coefficient depends onmanagement parameters, personal ability, logistic utility and equipment, tunnel characteristics, objectivesand geological conditions. Although in each of the main models same as CSM, NTNU and QTBM, thespecific parameters used to estimate the utilization coefficient, the effect of management factor andinteractions and overlapping factors not considered. On the other hand, many parameters have a severedependence on each other and may simultaneously affect the performance of the TBM. Therefore, theinteraction matrix can be used to evaluate the interaction of parameters on each other and on TBMperformance. The effect of 18 parameters on the utilization coefficient was evaluated by the matrix methodin Karaj water conveyance tunnel. The interactions of these parameters show that the lack of utility servicesand shift change have the most significant impact on TBM performance. By recording the actual delays ineach parts of tunnel, the downtime index (DTI) is obtained; this index has a direct relationship with tunnelboring time and is inversely related to TBM performance