On The Stability Of The Compound Soil Nailing In The Deep Foundation Ditch

In this paper, the applications and the stability analysis of compound soil nailing were studied. Based on the fact of the applications and the researches on compound soil nailing in land and overseas, it were introduced that the applications and the researches on compound soil nailing in land and overseas nowadays. Based on the formers' results, this paper has established non-linear FEW calculation modes. According to the results of non-linear FEW and the data of field in Wuhan, this paper summarized the bearing and deformation mechanic of the composite soil-nailed wall. The main researches are as follows:1. Review the composition and the constructions analyze its engineering characteristics of the main of form construction, its method and techniques characteristic.2. The orthogonal experiment method is applied in the analysis of foundation ditch, studied 11 factors to the mixing pile-soil — soil nailing supporting of the sensibility of stable states, got all of the factors on the influence rule of the stability of supporting structure. These 11 factors, which respectively are including: length of soil nailing, insert deepness of piles, friction force of soil nailing interface, declination angle of soil nailing, horizontal spacing of soil nailing, rows of soil nailing, unit weight of soil, friction angle, unit cohesion, overload of slope, diameter of soil nailing.3. Aimed at the characteristic of the constructing composite soil-nailed wall, the paper has established non-linear FEM calculation mode, including simulation of soil, mixing pile-soil, soil-nailed, Goodman interface element.4. According to the data of the field measurements, this paper has used non-linear FEM separately in different geology conditions, analyzed deformation characteristics, internal force and extension areas destroyed regulation of the composite soil-nailed wall during the progress of the construction and summarized the bearing and deformation mechanic of the composite soil-nailed wall. Geology conditions have decided the bearing and deformation mechanic of the composite soil-nailed wall. In the loose-soft soil and the area full of underground water, the maximum horizontal displacement is located in middle of the wall, and the maximum vertical displacement is located in the middle of the upside load. In the more strength soil, the maximum horizontal displacement is located in the top of the wall, and the maximum vertical displacement is located in the edge of deep excavation pits, so it looked as "decline slope".5. Based on the data of the field measurements and the calculation's results, this paper has summarized the bearing and deformation mechanic of the composite soil-nailed wall in the different geology conditions, and this useful research results have provided the theoretic foundation for this technology. According to the calculation's results and the working skills of the field, this paper has given some beneficial advices on the composite soil-nailed wall's design and work.