Study On The Application And The Stability Analysis Of Compound Soil Nailing

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. With the engineering applications of compound soil nailing, main types of compound soil nailing and their working mechanism were analyzed. The stability of compound soil nailing was also analyzed. During the stability analysis, the safety coefficient and the most dangerous slipped layer of soil slope retained by compound soil nailing was studied. The stability of soil nailing was calculated. Then, the influence functions of water, prestressed anchor and cement-soil retaining wall and front small-piles in the compound soil nailing system were studied. The corresponding formulas were given. A model test of the compound soil nailing for deep excavation was carried out in laboratory in order to study the working mechanism of compound soil nailing deeply. The retain effects of compound soil nailing and those of soil nailing were compared in this experiment. At the last, some civil engineering structures retained by the compound soil nailing were introduced.The results of theory researches show that the selection in the types of compound soil nailing should base on the geologic condition of soil slope. The working mechanism of compound soil nailing depend on the soil nailing mainly, the other part such as prestressed anchor and cement-soil retaining wall and front small-piles in the compound soil nailing system can also take part in. The researches on the stability of compound soil nailing show that it is important to determine the safety coefficient and the most dangerous slipped layer of soil slope retained by compound soil nailing in the stability analysis of compound soil nailing. Water, prestressed anchor and cement-soil retaining wall and front small-piles in the compound soil nailing system have a great influence on the stability of the whole compound soil nailing system. The front small-piles in the compound soil nailing system can improve the stability of the soil slope. The cement-soil retaining wall in the compound soil nailing system can increase the safety coefficient of soil slope retained by compound soil nailing. The prestressed anchor in the compound soil nailing system can increase the slipped resistant force JAevidently, and it make very important in controlling the distance nearby the excavation.The experimental results show that the deformation profiles of compound soil nailing were different from those of soil nailing, and the cooperation of the nail and the soil-cement piles can control the deformation induced by excavation effectively and improve the stability of the excavated slope.The applications of compound soil nailing on the civil engineering structures show that the compound soil nailing technology can retain the excavation and the soil slope in the complicated geologic condition. And it also shows that Selection in the types of compound soil nailing should base on the geologic condition of soil slope.