The influence of excavation damaged zone on the mechanical and thermal behavior of cement mortar block around an opening

To investigate the influence of Excavation Damaged Zone (EDZ) on the mechanical and thermal behavior, EDZ was artificially generated around an existing circular hole in a mortar specimen. By applying high compressive stresses on the boundaries of a specimen and repeating loading and unloading cycles, EDZ was generated around the hole. An engineering heater was installed at the hole and the temperature of the heater was maintained at 75°C during the tests. Tangential strains and temperature were monitored at several points around the hole and compared to those measured in the specimen without EDZ. For elliptical and circular damaged zones, the tangential strain in the EDZ increased by as much as 88% and 58%, respectively and temperature in the EDZ decreased by 2.8°C and 0.85°C, respectively. Two-dimensional thermal-mechanical coupled numerical simulation using Particle Flow Code 2D (PFC2D) was carried out to analyze and to demonstrate the experimental results. For the numerical simulation, thermal parameters were determined using the results obtained from sensitivity analyses by a factorial design method. The TM-coupled PFC2D modeling results indicated that significant changes in mechanical and thermal behavior were observed, when the elliptical and circular EDZ was considered. And that the laboratory test results were successfully reproduced.