نشریه مهندسی تونل و فضاهای زیرزمینی
سال نهم شماره 2 (تابستان 1399)

Many studies have been performed on fiber reinforced segmental lining for years, which is to improve some of the weak material properties of Segmental lining. Fiber-added reinforced concrete (FRC) applications have become widespread in areas such as, tunnel shells, concrete sewer pipes, and slabs of large industrial buildings. Usage of FRC in load-carrying members of buildings having conventional reinforced concrete (RC) frames is also gaining popularity recently because of its positive contribution to both energy absorption capacity and concrete strength. The paper is focused on the mechanical properties of the designed structural steel fiber reinforced concrete (SFRC), which are important for the capacity of the tunnel lining segments and their damage during manipulation. Generally the segments are more loaded during tunnel lining installation (long term load is lower). The realized investigation was focused on SFRC with various types of fibers, such as steel fiber and synthetic fiber. The use of fiber reinforced concrete for the Golab tunnel segments was examined, but for the highly loaded big rings with high bending moments and normal forces, a high amount of bar reinforcement is necessary

Empirical and numerical methods are commonly used when underground engineering structures are designed. Empirical methods are generally preferred by rock engineers and geologists due to their practicality. In designing tunnel supports, rock mass classification systems, RMR, Q, and RMi have been used by many researchers and gained universal acceptance. These classification systems have been originally obtained from many tunneling case studies and they have been applied to many construction designs. It is necessary to select the appropriate parameters as inputs to these systems in order to accurately describe the rock behavior. Therefore, researchers tend to look more closely at the input parameters. RQD and FS, two input parameters to RMR, and recently introduced parameter FF as their alternative, has been discussed in this paper. Also, the applicability of FF has been investigated on Alborz tunnel data as a case study. Traditionally, parameter ratings were determined from the presented tables for RMR. However, some users were not aware that the ratings in these tables were the average values for the ranges shown and not the minimum values. For improved accuracy, it is better to use the recommended graphs, showing the continuous value of the ratings. Therefore, the presented graph was used to determine the value of FF parameter as a combined rating of RQD and FS. RMR13 has obtained by replacing FF rating instead of the total rating for RQD and FS in RMR89. The values obtained for FF rating were highly correlated with the total rating for RQD and FS. Also, the total rate of RMR13 was similar to RMR89 with a correlation coefficient of 0.996, the values obtained for RMR13 was approximately 2 percent higher than these for RMR89. In general, using both versions of RMR are practical and acceptable, but the choice of each to use, depends on the project conditions and system user capabilities.

The prediction of the surface settlement and ground displacement due to the underground excavation is a key factor for the stabilization and planning to control probable incidents. Due to the real condition and natural modeling materials, physical modeling has critical role in this area. In this research, a series of physical model tests was conducted to study the influence of tunnel depth on the ground deformation and ground surface settlement in a loose sandy ground. Particle Image Velocimetry (PIV) technique was used, as a non-destructive image processing technique, to measure the ground deformation and surface settlement during the tunneling process. The results show that in case of a sloping ground surface, the settlement trough is asymmetric and the deformed zone and ground settlement in extended upward the slope. Although the maximum surface settlement still appeared along the crown of the tunnel, its value increased up the 25%, compared to a horizontal ground surface with a tunnel at the same depth. The deformed areas in the models were divided into two district portions; the deformed zone close to the tunnel and the deformed zone close to the ground surface. In the deformed zone close to the tunnel, in general, the dip of the boundary increased with an increase of the tunnel depth. Moreover, the lower side boundary was about 10 degrees steeper that the upper side boundary. In the deformed zone close to the ground surface, the deformed boundary has an inclination of 54 degrees for all the models, independent of the tunnel depth. .

Cutter life is one of the major hard rock TBM performance parameters which has a direct effect on the total cost and completion time of a tunneling project. Major influential factors of the cutter life include geological parameters as well as operational and design characteristics. In this regard, the operational parameters are not deeply investigated in combination with other factors mentioned. In this paper, the results of statistical analyses of the cutter life information of Ghomrud water conveyance tunnel project (lots 3 and 4) along with its influential factors are presented. The results show the cutter rolling and normal force are among the most influential factors of the TBM operational parameters. A combination of these two along with uniaxial compressive strength gives a multi regression formula with a coefficient of determination of 75%.

In this study, with the aim of investigating the thermal performance of an eartshelterd building, the amount of energy consumption in an earthshelterd construction model at different depths of the soil was compared with a building located on the ground surface. To this end, first, modelling was carried out with Sketchup software, then, soil temperature in the city of Shiraz at different depths was extracted utilizing the relevant formula and weather information obtained from Meteonerm software to enter in EnergyPlus software for performing thermal simulation. Consequently, considering the parameters considered for the city of Shiraz, the annual energy consumption saving measured, respectively for cooling and heating loads for a building located at a depth of 6 meters as optimal depth that was about 50 % and 20 % more than the non-earthshelterd building located on the ground surface. Therefore, replacing underground spaces instead of an on-the-ground building is a solution that is suggested for reducing annual energy consumption in buildings. Hence, in this research, the cooling and heating energy consumption as one of the most popular species of the green construction method in Shiraz with a hot-arid climate and prone to the development of earthsheltering architecture is investigated