Interior Stability Analysis Of Soil Nail Wall Optimization Algorithm

In deep excavation design, the safety factor for the interior stability analysis of soil-nailed wall is mainly computed by Swedish slice method. Unfortunately, the Swedish slice method has poor computation precision and cannot truly evaluate the interior stability of soil-nailed wall because it can only meet the moment banlance of slice. On the other hand, the interior stability of soil-nailed protecting structure always behaves the constrained optimization problem because of the non-uniformity of soil material. Its target function is always the implicit function with multiple maximum and noncovexity. Furthermore, it always falls into the locally optimal solution when using the general optimization algorithm to search for the slip surface of soil-nailed wall. To solve the problem presented above, firstly, on basis of the principle of simple Bishop method and by considering the consolidation of soil-nail, a new computation formula of stability safety factor for soil-nailed wall is established. Then, a new type of optimal algorithm, i.e., the Tabu search Genetic algorithm (TSGA) is proposed through combing the merits of simple genetic algorithm (SGA) and tabu search algorithm (TSA). Furthermore, applying TSGA into the field of soil-nailed wall interior stability analysis, an optimal algorithm for searching circular critical slip surface was established. The main achievements of this dissertation are as follows:(1) Based on the principle of simple Bishop method and by considering the consolidation of soil-nail, a new computation formula of stability safety factor for soil-nailed protecting structure is established.(2) The disadvantages of simple genetic algorithm (SGA) and tabu search algorithm (TSA) are firstly analyzed. Then, a new type of optimal algorithm, i.e., the Tabu search Genetic algorithm (TSGA) is proposed in this dissertation through combing the merits of SGA and TSA. Simulating results show that TSGA has higher global searching efficiency than SGA and TSA.(3) Taking the minimum safety factor as the target function and on basis of TSGA, a global optimization method which can locate the circular critical slip surface and the corresponding minimal safety factor of soil-nailed wall is presented in this dissertation, In the end, the influences of dip angle of soil-nial and earthquake on interior stability of soil-nailed wall are discussed.