نشریه مهندسی تونل و فضاهای زیرزمینی
سال نهم شماره 3 (پاییز 1399)

One of the most important goals in the design process of the TBMs is to determine the proper positions of the peripheral cutters. Since the actual penetration of the peripheral cutters in the tunnel face is lower, the normal force applied by them to the tunnel face is also lower. In order to avoid ridge formation between these cuters and to avoid asymmetric forces applied to the flanks of the cutters, it is necessary to gradually reduce the cutter spacing in the peripheral area of the cutterhead. The design of the peripheral cutters’ parameters (spacing and tilt angle) are usually performed experimentally, and there is no theoretical background for it in the literature. In this paper, an empirical model is introduced to determine the optimum configuration of the peripheral cutters on the cutterhead profile. This model is developed based on the principles of the optimum excavation using the optimum ratio of spacing to penetration rate (S / p), as well as the information of design details of a number of hard rock TBMs from around the world. The results of this model provide the optimum spacing of disc cutters and their corresponding tilt angles and normal forces for the peripheral cutters.

In the present study, the feasibility of implementing the shallow tunneling method (STM) for the Abshenasan (Z6) subway station construction in geological conditions of Tehran's alluvium was conducted numerically based on the evaluation of deformation and subsidence of the ground surface. The numerical modeling process was performed in three-dimensional method using Plaxis finite element software. The results obtained from numerical modeling using the STM method show a significant reduction in the deformation and surface subsidence compared to the traditional pile and rib method. So that the maximum subsidence estimated at ground level is about 6.09 mm and is related to the front of the face excavation. This amount of deformation and displacement behind the face excavation was recorded at a distance of approximately one times the width of the station at about 3.52 mm. In fact, with the implementation of the STM method for the Z6 station, the deformation and displacement of the ground occurred at a lower rate than the pile and rib method, resulting in a reduction of maximum subsidence in the ground surface.

Drilling and blasting are considered to be one of the most widely used tunnel excavations due to their advantages such as flexibility. It is very useful to design an accurate and optimal blasting pattern to achieve high progress, lower cost and also to prevent out-of-plan phenomena. Blasting pattern design is a time-consuming process, and achieving an optimal blasting pattern requires repetition of designs and selection of the best pattern. Therefore, the existence of a computer tool can be useful in reducing the time of calculations and designs. In the present study, a software was developed to design the blasting pattern of underground spaces using 9 widely used methods including parallel and angular energy transfer methods, Norwegian, Holmberg and Persson, Gustafson, Lopez and Olofsson simplified models and Konya parallel and angular methods. In this software, project input including face dimension, substrate and explosive properties are taken from the user using forms. After entering the input and executing the project, the design results of the blasting pattern are calculated and provided to the user in two ways; It is displayed both graphically in the software and its details are stored in the user's system along with the project inputs. Also, the key parameters of blast pattern design, including powder factor and drilling factor, are calculated and displayed along with the results of blast pattern design, and the user can select the appropriate pattern according to the existing conditions. Finally, manual designs were used to validate the software results. Comparison of the results showed that the software provides a suitable layout for the holes in different methods and calculates the amount of powder factor and drilling factor with less than 12% deviation. Among them, the results of software design with manual design in Norwegian and Olofsson methods have the least deviation in terms of powder factor and drilling factor. Minor differences in results with manual design can be due to the rounding of numbers and the layout of product holes. With the development of the present research software, the platform for receiving input information of a tunnel project in order to automatically design of blasting patterns is provided and blasting patterns are designed in 9 methods automatically. These patterns are displayed graphically in the software environment and report the key parameters of each pattern, including powder factor and drilling factor associated with that pattern. When the template is selected and approved by the user, the selected template is printed as an executable copy.

In this paper, the seismic response of the surface in the presence of a circular underground lined tunnel subjected to vertical incident P/SV and SH-waves were obtained. In this regard, the three-dimensional (3D) finite element method (FEM) approach in the framework of ABAQUS numerical software was used for preparing the model. At first, a brief presentation of FEM formulation as well as solving a validation example was carried out. Then, by considering some key parameters such as tunnel depth, and the impedance ratio of the lining, the response of the ground surface was sensitized. In the following, a comparative study was performed between the responses of 3D-FEM and 2D half-plane boundary element method (2D-BEM). The results showed that the mentioned parameters are very effective in the formation of different patterns of ground motion. Furthermore, a slight increase of amplitudes is observed in the responses of the 3D approach compared to 2D modeling. The results of the present study can be used to complete the accuracy of existing seismic codes around the subject of micro-zonation of the site in the presence of subsurface openings as well.

The diversity, multiplicity and extent of the presence of examples of troglodytic architecture in Iran confirm their significance in Iranian architecture. Despite numerous research records about these examples and despite the multiplicity of names proposed for them, a holistic and comprehensive definition of this type of architecture is not available. This situation prevents a comprehensive understanding of troglodytic architecture. Therefore, the article seeks a comprehensive definition of this type of architecture and has addressed the two aspects mentioned in this regard. In the first aspect, an attempt has been made to define this type of architecture based on the six categories of Smith Capon, namely function, form, meaning, construction, texture, and spirit. In the second aspect, it has sought to introduce the design methods of this type of architecture throughout history.

Methodology and Approaches:

 The present article uses an extensional definition as well as an analytic definition to define troglodytic architecture. In the extensional definition, one refers to examples or instances of defining a phenomenon. In the analytic definition, which has much validity in logic and beyond, the phenomenon in question is defined by decomposition into different types. Therefore, this article has been conducted by relying on examples of Iranian architecture and its different types. The present study has used written texts and direct references to examples to collect data.

The results show that the definition of troglodytic architecture in the first aspect that is the product of this type of architecture, can express several features of troglodytic architecture through the introduction of six categories and also different criteria. For this purpose, the category of function is explained in terms of type and continuity of performance; the form category according to the shape of entering the space, the shape of the space organization, the shape of the spaces, and the shape of the cover; the category of meaning in terms of historical breadth; the construction category according to the type of land excavation solution, type of land excavation technology and implementation method; the texture category in terms of neighborhoods and spatial scale; and the spirit category in terms of land benefits. In addition, the results indicate that the evolution of the processes used in the design of these examples can be introduced in the form of three instinctive-imitative, experimental and scientific models.

From a seismic geotechnical point of view, the effect of underground structures such as inner tunnels on the seismic response of the earth's surface and the surrounding environment has been revealed by researchers. In this paper ، considering the building-soil-tunnel system interaction ، the effect of shallow tunnel presence on the seismic response of the 20-story, SAC benchmark building is investigated. The building-soil-tunnel interaction system is modeled in two dimensions and considering the nonlinear behavior of soil materials using the equivalent linear method. 8 benchmark earthquake records have been used to evaluate the seismic performance of this building. In this study, the effect of horizontal and vertical tunnel distance, excitation frequency, and flexibility ratio, as well as site soil type on the seismic response of the building, has been investigated. The results show that for the sine wave, the maximum effect of acceleration magnification is observed in the horizontal distance ratio of 4, and by decreasing the dimensionless period ratio, the tunnel effect on the magnification increases due to the passage of waves with shorter wavelengths. Additionally, the maximum roof displacement and base acceleration for soil type IV are larger than type III and type III is larger than type II. Also, for soil type IV, the maximum amplification of roof displacement and base acceleration is 54 and 46 percent respectively.