COMPARISON OF SOIL NAIL AND COMPOSITE SOIL NAIL REINFORCEMENT STRUCTURES USING NUMERICAL SIMULATIONS

Foundation pits.In this paper,the authors use SnEpFem software to evaluate several alternative soil nail reinforcement structures: soil nail along,pre-stressed anchor plus soil nail;miniature pile plus soil nail;and miniature pile,pre-stressed anchor plus soil nail.Comparison of all four alternatives is done for the characteristics of horizontal deflections,ground surface settlements and the range of settlement,pit bottom uplifts and the areas of tension and plastic zones.It was concluded that(1) Compared with simple soil nail reinforcement structure,composite soil nail reinforcement can control slope distortion in effect,and reduce the areas of tension and plastic zones.Consequently,composite soil nail reinforcement structures can improve slope stability.(2) Setting miniature pile controls horizontal deflections better than adding pre-stress.(3) Setting miniature pile can efficiently control ground surface settlements,however,adding pre-stress influences it a little.(4) The effect for pit bottom uplifts is consistent in all the reinforcement structures,and the values vary a bit.By comparison,under this engineering geologic condition, of all the composite soil nail reinforcement structures,the most dependable one is miniature pile + pre-stressed anchor + soil nail reinforcement structure.Its distortion,settlement and the areas of tension and plastic zones are least in the four structures,and it is the most excellent reinforcement structure.