| Landslide is one of the main earthquake-induced geological disasters,and landslide control has become an important work for disaster prevention and relief.Micro-pile is a new supporting structure,which is widely used in earthquake relief and landslide control because of its high flexibility,short construction period and small disturbance to soil.Scholars at home and abroad have made perfect research on the statics of micro-piles,but the research on the deformation characteristics of landslide reinforced by micro-piles under earthquake is relatively few,so there is still a great space and prospect for the research on the dynamic characteristics of micro-piles.In this paper,according to the distribution law of the accumulation landslide in southern Shaanxi and the simplification of practical engineering,taking the 20-degree slope as the research background,the angle of herringbone micropiles is defined as the angle between single pile and vertical direction,and four reinforcement schemes of 5,10,15 and 20 are selected.Based on the theoretical basis of numerical simulation software FLAC3 D and advanced soil mechanics,and considering the expansive characteristics of soil,herringbone micropiles with different angles are used.Contrast analyze the displacement change of slope,horizontal and vertical displacement of pile top,distribution law of axial force,bending moment and shear force of pile under different magnitude and direction of earthquake acceleration,get the optimal layout angle,and provide suggestions for seismic design of micro-piles.The conclusions of this paper include the following contents:(1)When the peak acceleration is from 0.1g to 0.2g,the slope displacement,the top displacement of the pile,the axial force,bending moment and shear force of the pile body are increased.In the four reinforcement schemes,as the angle increases;The slope displacement,horizontal displacement of the pile top,axial force,bending moment and shear force of the pile body are reduced;There was no significant difference in vertical displacement.When the peak acceleration is from 0.2g to 0.4g,the slope displacement,the top displacement of the pile,the bending moment and shear force of the pile body are increased,and the axial force of the pile body is reduced.In the four reinforcement schemes,with the increase of angle,the horizontal displacement of the pile top,the axial force of the pile body,and the bending moment are reduced.The shear force of the pile body is increased;There was no significant difference between the slope displacement and the vertical displacement of the pile top.(2)When the acceleration is the same,when loading in the three directions of acceleration in X,XZ and Z,X is displacement towards the slope body,horizontal displacement of the pile top,and the axial force and shear force of the pile body are the largest;The vertical displacement of the pile top is maximized by Z and XZ loading;Loaded in the X and XZ directions,it has little effect on the bending moment.(3)According to the dynamic response law of four different reinforcement schemes under earthquake,when the 20° "herringbone" pile is reinforced on a 20° slope,the axial force and bending moment are the smallest under various working conditions,and the horizontal displacement is the smallest.Increasing the angle increases the seismic level of the miniature pile,but the shear resistance is reduced.In view of the problems in the seismic design of 20° micropiles,connecting beams can be selected at the top of the pile for reinforcement,and reinforcement can be added to improve the overall seismic effect of the pile body. |
