Seite - 1419 - in Book of Full Papers - Symposium Hydro Engineering

Section analysis of the borehole BH-22 in the earthquake state with 0.15 factor for pseudo static calculation indicates decrease in the safety factor to 1.153. Under such conditions, the allowable safety factor can also be acceptable for highest slopes in the allowable range. As the obtained factor is higher than the allowable value, the section has no earthquake problems, too. Borehole BH-23 has been drilled at El. 765.2 m.a.s.l. at the right abutment and its drilling depth is 35.2 m. Based on the above-mentioned conditions, drilling section of the trench different layers has been prepared based on the pressure meter and other tests in Geo- Slope mathematical model and the stability analysis has been carried out under test conditions and with earthquake. Under conditions without earthquake, the calculations show that the safety factor of the soil or trench excavation at the right abutment in highest slope is 1.798, which is higher than the allowable values of 1.4 to 1.5 and can be acceptable. Calculated safety factor of the analyzed section of borehole 23 under earthquake conditions with 0.15 factor is at least 1.294, which is higher than the allowable value of 1.05 and can be acceptable. Borehole BH-24 has been drilled at El. 756.28 m.a.s.l. whose maximum excavation is 26.28 m down to the spillway bottom. Analysis of this height under pressure meter test conditions shows the safety factor as 3.351, which is mainly due to the decrease in the excavation height and the safety factor is actually a large one. Section analysis of borehole BH-24 has been carried out under earthquake conditions with0.15 factor, whose safety factor has been calculated as 2.4. The minimum safety factor under exceptional load condition is 1.05 but the obtained safety factor is considerably larger and this slope is in the safety margin. Critical failure wedge for excavation based on pressure meter test in borehole 24 plus earthquake with 0.15 factor. Borehole BH-25 has been drilled at the left abutment, at El. 760.51 m.a.s.l. and its analysis has been carried out for both with and without earthquake conditions, where the calculated safety factors have been estimated as 2.094 and 1.464, respectively, which are totally above the comparing allowable minimums of 1.5 and 1.05 and so, it is actually acceptable. Borehole BH-26 has been drilled at the left abutment, at El. 754.28 m.a.s.l. and its analysis has been taken into consideration based on the carried out pressure meter tests. For the soil excavation height of almost 25 m, the calculated safety factor has been estimated as 2.003. Allowable safety factor in this state has been 1.5, which is acceptable under such conditions. Based on the information obtained from the pressure meter tests, the critical section crosses the berms in the first 15 m, i.e. due to the material properties; it is in lower elevation layers to the bottom excavation. Calculation of the safety factor in earthquake conditions for the borehole BH- 26 has been carried out with earthquake factor of 0.15, where the safety factor has been shown as 1.468, which is higher than the allowable minimum of 1.05 and it is acceptable. 1419