The upper bound solution of the factor of safety is obtained by optimization calculation. To evaluate the feasibility of the method proposed in this paper, it was compared with the safety factor calculated by the marginal equilibrium method. Were the method to evaluate the stability of the tunnel face in the framework of the upper limit theorem. Consists of two newly defined parameters: one normal stability ratio and the critical stability ratio. Therefore when the initial tunnel is stable or unstable, the relationship between the electric field stability ratio and the critical stability ratio is determined. The stability of the tunnel surface is estimated by the upper limit theorem of the limit analysis together with the strength reduction technique by the safety factor widely used in the slope stability analysis. There are two methods to reach the critical steady state by increasing the tunnel according to the field stabilization factor. One is to calculate external work (increase the external load) and the other internal energy dissipation in a kinematically acceptable velocity field (decrease the internal load). The tunnel bearing capacity relationship is arranged to reach the critical stability ratio of the two external force enhancement methods. In this way, the upper limit solutions of single tunnels, twin tunnels of the same diameter, and twin tunnels of different diameters are analyzed. TAs a result of the comparison, the solutions derived from these two methods agree well with each other, so the method proposed in this paper can be considered effective. تفاصيل المقالة

Landslides are present on all continents playing important role in the continual evolution of this type of similar geohazard. They constitute a serious hazard in many areas of the world. Most of Iran's land is covered by mountainous areas. One of The dangers that always threaten these areas are the instabilities of the slopes. The occurrence of this phenomenon causes a lot of damage to the cultivated lands every year Human enters. Among these, one of the most dangerous domain instabilities Landslide is a phenomenon. Kurdistan province and within the study area (Bane city) as a part of the province, is one of the areas that due to the conditions geological, topographical, and climatic specifics along with the human factor, in some places, is prone to landslides. The most important of these landslides can be found in Gardaneh Khan, Savan, Sabdlo, and Dar. Finally, an ALUT is pointed out as an indicator. Therefore, identifying the process of landslides is necessary to identify, investigate and determine the causes of landslides at the level of the regions of the country it arrives in this study, the paper also discussed the manifestation, causes, and effect of landslides. For geotechnical analysis, samples were collected from the landslide site and subjected to the following tests: natural soil moisture content, specific gravity, relative density, shear strength, and compaction permeability. Adjacent slopes of still intact slides were also analyzed using Plaxis 2D to determine their safety factor. Both the geotechnical laboratory results and the Plaxis 2D results show that without the improvement of the infinite slope condition using the method recommended in this paper, another landslide will inevitably occur. Several of the methods recommended include cutting back of slope to reduce its gradient, reinforcements, soil nailing as well as anchors and retaining structures. تفاصيل المقالة