In a perfect design of underground spaces, amount of total displacement from the point of stability analysis is fundamental. In empirical and numerical stability analysis periphery of excavated area is consider as a continued mass. When an underground space is excavated by blasting process, so periphery of tunnel is damaged by that process. As a result, those materials are not continued. In this research this area named "Crashed areola". 3 dimensional distinct element methods has more adapted with this area, while compared to other numerical methods. 3DEC 4.0 which is based on this method was chosen as a numerical codes. 10th kilometers of Gavooshan tunnel which is water conveyance tunnel is considered as a case study. The part of this tunnel which studied in this research is surrounded by ophiolithic gabbro rock mass. For modeling of this tunnel two conditions were considered, first with continue media of rock mass and second discontinue media so called crash areola. One of the advantages of this part of tunnel is installation of instrumentation with very scientific methods and absence of lining in the other band. The outputs of numerical solution were shown that modeling by considering crash areola is near to data collection by instrumentations.