Improvement of Rock Bolt Profiles using Analytical and Numerical Methods
The anchorage capacity of fully grouted bolts has been studied for many years, however the bolt rib profile and its effect on bolt shear resistance is poorly understood. A new development in calculating load transfer capacity between two rib profiles of varying geometries is discussed. The derived mathematical equations presented calculate the stress distribution adjacent to the fully grouted bolt and bolt pull out force needed to fail the resin. The Fast Lagrangian Analysis Continua (FLAC) program was used to verify the calculations of stress within the resin. The novel idea of coupling the bolt geometry with the calculated stress provides another powerful tool to investigate the bolt profile configuration and its effects on the load transfer mechanism for the benefit of the mining industry.
Optimization of the fully grouted rock bolts for load transfer enhancement
The purpose of this study is to investigate the role of bolt profile configuration in load transfer capacity between the bolt and grout.Therefore,five types of rock bolts are used with different profiles.The rock bolts are modeled by ANSYS software.Models show that profile rock bolt T3 and T with load capacity 180 and 195 kN in the jointed rocks,are the optimum profiles.Finally,the performances of the selected profiles are examined in Tabas Coal Mine by FLAC software.There is good subscription between the results of numerical modeling and instrumentation reading such as tells tale,sonic extensometer and strain gauge rock bolt.According to the finding of this study,the proposed pattern of rock bolts,on 7 + 6 patterns per meter with 2 flexi bolt（4 m） for support gate road.
Frequency selective surface design for blinds applications
In this paper, the reconfigurable blind structure with frequency selective surfaces(FSS) for the building applications are presented. Frequency transmission characteristics for different angles of the proposed blind-FSSs are investigated and verified through simulation and measurement. The simulation results show that we can implement the reconfigurable blind-FSS for multiband wireless applications. To verify the proposed paper, two kinds of blind-FSSs, crossed dipole FSS and circular ring FSS are fabricated and measurements are performed for different angles. The proposed structure in this paper which is very simple, can be easily applied to any planar surface for wireless security applications at low cost.