| The existing soil nail wall is an isometric soil anchor support,so this paper puts forward a new type of multi-plate soil anchor support of the soil nail wall,In order to study the soil deformation,the shaft force of soil nails,the influence of side mo resistance and other factors,the FLAC3D5.0 numerical simulation software is used for numerical analysis.(1)This paper summarizes the form of foundation pit support deformation,and puts forward a multi-plate soil nail wall,introduces the multi-plate soil nail support structure,describes the support mechanism of multi-plate soil nail wall and the factors that affect deformation of multi-plate soil nail.The preparation of multi-plate soil nail is introduced,which is to drill holes first,and then use a widening tool to expand holes in the well-drilled holes to form a disc cavity,insert threaded steel bars,pour into cement slurry or cement mortar,after curing can get multiple plates of soil nail.(2)Using FLAC3D numerical simulation wall height of 6 meters,soil nail length of 5 meters,inclination of 15 degrees,three layers of multi-plate soil nail support,the disc spacing of 5d(d for rod diameter),disc diameter of 1.5d,disc thickness of 1.Od,plate number of 8 Multi-plate soil nail support,compared with the same length and equal diameter soil nail,digging to the bottom of the pit,multi-plate soil nail in the base pit slope horizontal displacement maximum value decreased by 63.4%,pit field surface maximum subsiding value decreased by 66.3%,the maximum axis force value decreased by 16.4%,And multiple plates of soil nail reduce the area of the sliding surface.Its supporting effect is the same as that of the equal diameter soil nail with length of 2.8L(L is the length of multi-plate soil nail).(3)The orthogonal experimental method is introduced into the analysis of multi-plate soil nail engineering.A total of 9 groups of numerical simulations are set to study the sensitivity of the diameter,number and spacing of disc to the horizontal deformation and settlement of the foundation pit.The results show that the order of deformation sensitivity is:diameter,number and spacing of multi-plate.(4)On the basis of sensitivity study,the influence of the diameter,number and distance of the plate on the deformation of the foundation pit is analyzed by using FLAC3D5.0 numerical simulation software.A total of 17 groups of multi-plate soil nailing supporting models were set up.According to the deformation curve of foundation pit and data analysis,the optimal plate diameter was 1.5d and the optimal disc spacing was 3.5d.The disc body were distributed equally along the length direction of soil nailing as far as possible.(5)To study the multi-plate soil nail layout,multi-plate soil nail length and multi-plate soil nail angle on the deformation of foundation pit,a total of 13 groups of foundation pit models were set up,according to the deformation figure to analyze its change law,eventually the multi-plate soil nail should be arranged by the gradual shortening,the length of multi-plate soil nail should be less than 1.6 times of the excavation depth,multi-plate soil nail as far as possible along the horizontal layout.Figure[44]table[7]reference[61]... |
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