关键词: 黄土高边坡, 土钉-预加固桩, 性状, 动态监测, 有限元, 稳定性分析

Abstract: The combination of soil nails and stabilization piles (CSNSP) has been widely used as a reinforcing technique to retain excavations and stabilize slopes, but few relevant applications are found for high loess slope. Based on a high steep loess slope strengthened by CSNSP, the behavior of the strengthening system is investigated by field monitoring and finite element method. The results show that the lateral displacement, shear force and bending moment of piles increase gradually with the increment of excavation depth; and the displacement tends to be steady gradually. The location of the maximum shear force in the pile body shows a declining trend which indicates that the potential failure surface develops downwards. The distribution of soil pressure around piles in CSNSP system is compared with which appeared in deep foundation pit. The soil pressure on the back side of piles shows a trend of decrease with excavation while the soil pressure on the front side appears to be fluctuant. With the growth of excavation depth, the measured stress of the reinforced soil nails increases significantly, which indicates that the slope deformation is limited by the soil nails. The most dangerous rupture surface of the slope above piles appears to be a circular arc and the shear opening locates at the head of the piles. In addition, the proportion of soil nails to stability for the overall system is larger than the stabilization piles when the excavation depth is shallow, but the situation changes with the increment of the excavation depth.

Key words: high loess slope, combination of soil nails and stabilization piles (CSNSP), behavior, dynamic monitoring, finite elements, stability analysis