Page - 1418 - in Book of Full Papers - Symposium Hydro Engineering

section and also based on the specifications of layers in each borehole and its height conditions, which include three analysis sections at the right abutment and two at the left. In other words, the section belonging to borehole BH-22, which is located at elevation 772 m.a.s.l, due to its more height, is more critical than other sections, and this is the fact shown in calculations, too. Calculations have been performed based on the Geo-Slope V5.16 mathematical model, Mohr-Culomb model of discontinuity and also according to the above-mentioned descriptions and assumptions and for each analytical state, calculations in earthquake conditions with 0.15 factor have also been taken into consideration. Mathematical model of excavation in soil and trench has been provided in figure 1, which has been prepared in Geo-Lope software program. 11. CALCULATION RESULTS Calculation have been performed in Geo-Slope V5.16 software program based on the Mohr-Culomb model of discontinuity and Modified Bishop linear method [7,8,9]. The first analytical section belong to BH-22, which has been drilled at El. 722 m.a.s.l. at the right abutment and its pressure meter test results have been provided in table 1. Based on the information mentioned above, drilling section has been analyzed. The maximum Trench height is 42 m. Its slope stability safety factor, based on the pressure meter information and other tests, in this borehole whose different layers have been provided in the analysis has been calculated as 1.585. As safety factor for excavation geometry as shown in figure 4. Fig.4. Numerical model of excavation for slope stability Allowable values of the safety factor under stability conditions are 1.4 to 1.5 and therefore, the above-mentioned value is acceptable. Figure 2 shows the failure wedge along with the calculated safety factor. Critical failure surface mainly goes beyond the first 8meter. 1418