The 2nd Badong International Geohazards Symposium (BIGS2019)

88 / 2019-07-31 17:43:31

Study on the seismic interaction mechanism between micropiles and landslide

seismic interaction mechanism; micropiles; landslide hazards; shaking table test

Prevention and Control of Reservoir Geohazards and Ecological Environmental Protection > Technologies of geohazards Prevention and Control

A series of shaking table tests were conducted on two model landslides (unreinforced landslide and micropiles-reinforced landslide) to investigate the seismic interaction mechanism between micropiles and landslide.
The test results indicate that: (1) Micropiles can suppress the seismic waves, the acceleration of micropiles-reinforced landslide in the slope surface that supported by micropiles is weaker than that unreinforced landslide, especially for the toe. (2) For the piles above the sliding surface, the pushing force that behind micropiles are distributed triangularly, and the greatest pushing force is near the sliding surface. The resisting force of sliding mass before micropiles are quite small that they can be ignored; For the piles below the sliding surface, the earth pressure distribution of piles is greatly affected by the deformation of the pile above sliding surface. The resisting force of sliding bed behind micropiles is distributed triangularly, similar to the pushing force. The larger earth pressure is focused on the middle and the bottom part of piles. The resisting force of sliding bed before micropiles shows an inverted triangle type, and the greatest resisting force locates near the sliding surface. (3) When the landslide is stable, micropiles are only slightly bent under seismic waves, and the bending moment of each measuring point is not very different. However, when the landslide reaches the limit equilibrium state and instability state, the bending moment of each measuring point has a big difference. The maximum positive moment is in 3.7 times pile diameter above the sliding surface, and the maximum negative moment is in 1.4 times pile diameter below the sliding surface. (4) The failure mode of micropiles after earthquake can be defined as bending failure near the sliding surface, the flexural failure was observed in micropiles, and it mainly occurs in the area that 1.4~4 times pile diameter above the sliding surface and the area that 1.4~3.4 times pile diameter below the sliding surface.