Considering the progressive use of tunnels in the urban transportation networks، it is essential to investigate the reactions of these structures under seismic dynamic loads. For dynamic analysis of line 4 tunnel، the intersection of Tohid tunnel، line 4 tunnel and line 7 tunnel in intersection of Azadi street and Navab motorway have been studied. This junction is one of the more hazardous area in this project. Moreover، these tunnels have been excavated in different ground levels in soil. Therefore، the model is considered as a continuum media. The objective of dynamic analysis is the evaluation of tunnel support system stability under vibrations of probabilistic earthquakes. Findings prove that no damage occurs in the tunnel support system indicating no need to modify or improve the previously designed support system.

Predicting the behavior of urban tunnels in weak rocks with a behavior similar to soil's or rock's by swelling and squeezing ability is one of the important challenges in tunnel engineering and rock mechanics. In this research plane strain two-dimensional model of a real urban tunnel with horseshoe cross section is modeled through 2D nite element method. The aim of modeling is the investigation of the eects of considering or ignoring time factor in the constitutive model of materials on the interaction behavior of tunnel support system and also stress-strain and de ection behavior of surrounding rock masses.
For numerical modeling of tunnel-support system interaction two constitutive models including Mohr-Coulomb model(time-independentmodel),MC,andsoftsoilcreep model (time-dependent model), SSC, similar and constant rock mass properties were considered. The results of these two models in the framework of structural behavior of tunnel support system and also stress-strain and de ection behaviors of its circumference rock mass were compared. The results of study show that considering time eect on some cases caused an approximately 63 percent dierence between two model's results. For verication of research problem, a tunnel with similar conditions and jointed rock mass constitutive model in the frameworks of 2D and 3D nite-element analyses were used. The results of verication show good agreement between the obtained results by numerical models of the present paper and numerical models of the reference paper.
Mohr-Coulomb constitutive model is a model independent of time, stress history conditions, consolidation state, creep, hardening and softening, in order that no change could occur in the results obtained with this model in plastic numerical analyses by changing time intervals of numerical computations. However, considering creep of materials and time factor will generally increase the values of structural interaction parameters (secondary parameters such as bending moments, shear forces and axial forces in shotcrete and rock bolts) and geotechnical interaction parameters(initial parameters such as stressstrain relationships parameters, displacements and de ections of rock materials) of SSC model rather than MC model in the excavation of tunnel and installation of its support system. Impressibility of secondary parameters (i.e., structural parameters) in support system of tunnel compared to initial parameters (i.e. geotechnical parameters) is half by changing time intervals of implementationofcreepplasticanalyses. Inotherwords,with respect to the obtained results by changing real time in numerical analysis of geotechnical parameters (initial parameters) is approximately 2.30 times greater than structural parameters (secondary parameters), because the occurrence of geotechnical parameters will generate and mobilize secondary parameters (structural parameters) in the interaction of support system of tunnel-rock.

Select a support system of tunnels has an important role safety and economic status. This choice usually based on experience of designer engineers. But the question is always whether the best choice has been done?. In this study, Linear Assignment (LA) as the one of the most important method of multiple Attribute decision making (MADM), to select optimum support system of tunnels has been used. In this way the tunnel support system selection as a multi attribute decision making has been considered and the criteria for selection optimum support system include: support cost, safety factor, applicability, time installation, displacement and capable of mechanization. For this purpose, first, using the finite difference numerical method) FLAC2D (, various support systems based on technical parameters and stability of the tunnel has been identified. Then based on considered criteria, using the aforementioned optimum support system has been selected.

In this paper, DFN-DEM simulation using PFC3D software to evaluate the effect of joint intensity variation on tunnel support systems performance has been performed. Three dimensional distinct element software of PFC3D is considered for numerical modeling in this paper. This software has many advantages such as ability to create three-dimensional distinct joints with limited size and with different statistical characteristics, flexibility in different conditions and ability to monitoring a momentaril caving and falling during tunnel stability analysis. In this paper, at the first stage, by using of discrete fracture network (DFN) modeling and based on the surveyed data from access tunnel to the gallery of Rudbar Lorestan dam, fractures in this region have been simulated in the software and then is linked to the intact rock model. Finally, the performance of tunnel support systems of shotcrete and steel frame relative to change of the rock mass fracture intensity is investigated. The obtained results indicate more resistance of steel frame against fracture intensity variation compare with the shotcrete support system. Serious damage to shotcrete support system occurs by doubling the number of joints, while about the steel frame, serious damage occurs with four times the number of joints. Therefore, by increasing joint intensity which is caused by various factors such as explosions, earthquakes and etc, the steel frame support system has higher reliability.

Today, with advances in technology, enable the design and construction of accurate underground structures are provided. Nevertheless, the analysis of underground structures due to interaction between the soil or rock surrounding infinite medium and tunnel supporting system, is very complex and then lower research is done.
The response of tunnel supporting system under seismic loads is a function of the ratio flexibility of the lining and rock or soil medium. This ratio represents the stiffness difference between the ground and tunnel lining. And in fact, the interaction of the tunnel lining and medium is indicated.
Methodology and Approaches :In this paper, two analytical methods for investigating the underground spaces behavior under seismic loading is presented. Then, the response of tunnel monolithic lining in no-slip and full-slip conditions with using analytical and numerical methods with considering of interaction between tunnel lining and medium is investigated.
Results and The results showed that the stress induced by seismic loads in tunnel lining in no slip condition is 2.7 times higher than in full slip condition. Also, monolithic lining strain value in full slip condition is further than no slip condition. Results of numerical method shows good agreement with analytical methods.

When an underground space is drilled, the state of stresses is changed and a disturbance is created in the mechanical behavior of the surrounding Area. Stability of an underground space is provided by support systems. One of the most important loads in designing tunnel support system is environmental rock/soil loads. So far different methods have been represented to estimate the rock load such as empirical, analytical and numerical method that is based on engineering classification of rock. The aim of this study was to evaluate empirical and numerical methods of estimation of rock load on the segmental tunnel support system according to instrumentation data in the tunnel to transfer water from the Zayanderood dam to the city of Kashan. The results of numerical simulations, shows nearer results to field data.
In order to estimate the Rock load on tunnels, empirically, analytically or numerically methods those are useable for tunnel design engineers. Empirical methods are based on local observations, the required parameters in the project, comparing them with past experience and at last are based on the conclusions and determine the forces. In numerical method based on analysis stress, displacement and plastic zone is determined and rock load calculated. The most important advantage of this method for the simultaneous determination of the load on support system and deformation occurred in the rock mass. In estimating the Rock load for each of these methods sometimes large differences can be observed between the results from different methods.
Methodology and Approaches : In this research, all experimental methods available in the literature were evaluated. The SAP2000 and PLAXIS-2D software numerical modeling has been done. The results of empirical and numerical methods are compared with the results of field work and instrumentation and its results have been analyzed and interpreted. The results of the internal forces in the lining of software PLAXIS analysis and the results of the internal forces in the software SAP2000 (based on the rock of experimental methods) were compared and interpreted.
Results and Based on the results of numerical simulations, estimates of the analysis in Plaxis software for all host rock mass conditions, shows nearer results to field data. According to the analysis, the results of Goel & Jethwa and Goel et al. that based on RMR classification system using RMR Basic values as the closest approximation to field data to estimation of rock load have been introduced.

The distribution of earth pressure surrounding a tunnel is one of the most critical factors in designing tunnel support systems. In this study, a physical modeling setup has been designed and constructed to simulate the excavation procedure of a full-face circular tunnel. Silica sand was used with four different densities and three different cover-to-tunnel diameter ratios. The full-face excavation was simulated with a variation of tunneling-induced volume loss. The variations of earth pressure around the tunnel were measured by means of a series of miniature soil pressure cells. Particle Image Velocimetry (PIV), as a non-destructive image processing technique, was used to monitor the deformation of the soil surrounding the tunnel. The results obtained from both pressure cells and PIV showed that soil arching developed around the tunnel. As tunnel convergence increased, a loosened zone appeared above the tunnel, surrounded by a stress arch. It was discovered that there is a direct relationship between the height of the loosened zone and the depth of the tunnel. A linear equation has been established for the estimation of the height of the loosened zone, which has a direct influence on the design of the support system.

Today, due to the development of cities and the lack of space on the ground, as well as the increase in traffic problems, has resulted in increase of the need to build underground spaces to develop urban transportation systems. This study also examines the effect of the sequence of excavation of adjacent tunnels. The case study used in this study is the access tunnels of Iran Mall collection. For numerical modeling, the Midas GTS finite element software is used in 3D mode, and the effect of the sequence of tunnel excavation on the surface settlement and the internal forces of the structures of these tunnels have been investigated. The results showed that successive excavation of adjacent tunnels resulted in lower settlement values ​​than the simultaneous excavation of tunnels and had a significant effect on the temporary support of the tunnels in the values ​​of forces and bending moment. Finally, in order to validate the results of the surface settlement obtained from the numerical model, the monitoring data of the surface settlement of Iran Mall project were used, it was determined that the numerical results are close to the monitoring data.   Summary In this study, the effect of the sequence of adjacent tunnel excavation was investigated and the study sites of access tunnels of Iran Mall collection located in 22nd district of Tehran were studied. In this study, Midas GTS finite element software was used for design and simulation in three dimensions and the effect of tunnel excavation sequence on axial and shear forces and bending moment on the temporary support of these tunnels and surface settlement were investigated.   Introduction Evaluating the interaction between underground spaces with each other and also between these spaces with existing structures and providing appropriate solutions is one of the most important topics of tunneling in urban environments, which is of particular importance. In some cases, it is necessary to excavate tunnels in the vicinity of each other, which leads to significant impact effects. These interactions depend on the distance between the tunnels, the size of the tunnel cross section, the rigidity of the support system, and the method used to excavate the tunnels.   Methodology and Approaches Since numerical methods can be used to model the tunnel in different and complex conditions of soil mass and rock, and the stresses and displacements created around the tunnels as well as the forces and bending moment on the tunnel support system can be predicted with high accuracy. This research is designed and simulated using 3D Midas GTS finite element software.   Results and Conclusions The results showed that successive excavation of adjacent tunnels resulted in lower settlement values at the ground level than simultaneous excavation of tunnels and had a significant effect on the temporary support of the tunnels in the values of forces and bending moment. Finally, in order to validate the results of the surface settlement from the numerical model, the monitoring data of the surface settlement of Iran Mall project were used, it was determined that the numerical results are close to the monitoring data.

One of the most important parts of a tunnel are the supporting systems, which must be sufficiently resistant to loads during the life of the structure. Critical loads on the tunnel support system are ground and water loads, that are usually calculated separately by analytical methods.These loads have  coupled hydro-mechanical behavior in the materials around the tunnel and their effects on the structure should be considered as a connection phenomenon. Therefore, in this study, using two-dimensional finite difference method in FLAC software, a static design of the tunnel was performed, in which  the water was initially considered only as the pore pressure, and subsequently, static analysis was carried out completely in the form of coupling. One of the twin tunnels of Tabriz Metro Line 1 was used as a case study. For these two states, axial force and bending moment were evaluated and compared. In order to investigate the tunnel behavior under dynamic load, the real Duzce earthquake at the MCE level was selected. The axial force and bending moment in pure dynamic state and hydrodynamic coupling using Byron behavioral model were evaluated. The results showed that in the static coupled design, higher axial force of about 27% and lower bending moment of about 36% were obtained compared to the no-coupled mode. Also in the dynamic coupled design, more axial force and lower bending moment,  about 25% and 66%  respectively, were seen. Therefore, it can be concluded that it is best to use this state of structural loading for the detailed design of reinforced concrete structures.

Select a support system of tunnels has an important role safety and economic status. This choice usually based on experience of designer engineers. But the question is always whether the best choice has been done. In this study، Linear Programming for Multidimensional Analysis of Preferences (LINMAP) as one of the most important method of multiple Attribute decision making (MADM)، to select optimum support system of tunnels has been used and finally to achieve a single rating for the support system integration methods are used. In this way the tunnel support system selection as a multi attribute decision making has been considered and the criteria for selection optimum support system include: support cost، safety factor، applicability، time installation، displacement and capable of mechanization. For this purpose، first، using the finite difference numerical method) FLAC2D (، various support systems based on technical parameters and stability of the tunnel has been identified. Then based on considered criteria، using the aforementioned optimum support system has been selected. The study considered eight criteria that include: Vertical displacement in the roof of the gallery (C1)، vertical displacement of the gallery floor (C2)، the horizontal displacement at the corner of the side wall of the gallery (C3)، vertical displacement at the corner of the side wall of the gallery (C4)، safety factor (C5)، maintenance (C6)، the need for human resources (C7) and ease of implementation (C8). Since the access tunnel consists of two perpendicular tunnels، and each of the two tunnels to be divided into two areas are mineralized dolomite and dolomite The storage system of choice for the four regions are considered. In the first decision، the lowest safety factor storage system، a team of specialists is recommended; Then based on the results obtained with smaller amounts of the several options are proposed، decisions are removed from the list. Displacement parameters in different parts of the walls، floors and crown of the tunnel، safety factors and system maintenance cost indices are slightly And the economic analysis and numerical modeling have been achieved. Thus، the matrix is directly related Drays these numbers will be. Indices requires human resources and facilitate the implementation of quality indicators that are qualitative terms such as very low، low، medium، high and very high، have been evaluated. Quality indicators used for quantifying the scale is bipolar. Thus، instead of words is very low، low، medium، high and very high order of the numbers 1، 3، 5، 7 and 9 are used. Accordingly، the final decision matrix (slightly) related to the number one and two tunnels in the area of mineralized dolomite and dolomite، respectively. In this matrix، the indices of displacement in different parts of the walls، floors and crown of the tunnel، system maintenance costs and manpower required to have a negative aspect Safety and ease of implementation of aspect ratio and the indices are positive. Important factor in determining the indicators، the indicators were paired comparison matrix (a matrix of 6 × 6). Based on expert opinion and using the geometric mean weight of each of the indicators were. It is necessary to keep the system in selecting the weights for the two tunnels in two ranges، are the same. As was pointed out to select optimum maintenance system، the methods LINMAP as an important characteristic of decision methods have been used. As a general conclusion can be stated that in selecting a storage system for the tunnel، several indicators are considered. Way too many of the numerical method for determining the storage system، are used. Although many indicators are effective in the maintenance system But all these indices in a numerical analysis cannot be removed، Although one of the good work، behavior of the tunnel with the different options for a tunnel system is maintained. In a process of decision making using multiple indicators Evaluations to be made more scientific. In this study، eight different types of storage systems for the four different levels of access tunnels Goshfill mine was in 1565، Then consider the safety factor of at least 1. 2 for access tunnels، storage systems، 2 to 5 because of the safety factor of 1. 2 were excluded from the decision making process. The method according to other criteria LINMAP maintenance systems 1، 6، 7 and 8 were studied. Finally، the option 1 «to 4 meters in length and spacing of rock bolts have 1. 5 m in the roof and walls.» As the best system for the maintenance of the access tunnel was aligned Goshfill 1565.