| The anchor plate foundation has excellent uplift bearing performance,so it is widely used in various geotechnical engineering such as power transmission lines,tunnels,and slope protection.For a long time,the ultimate uplift bearing characteristics of anchor plates have been one of the research focuses in the field of geotechnical engineering,especially the more typical horizontal anchor plates.However,there is always an artificial distinction between shallow burial and deep burial in research at home and abroad,but there is no unified understanding of the value of the critical burial depth ratio of the anchor plate.There are few studies on the influence of the aspect ratio on the mechanical characteristics of the anchor plate.For quantitative description.The essence of the above problems is the insufficient understanding of the anti-pull bearing mechanism of the anchor plate,which causes the corresponding theory and standard methods to fail to provide comprehensive support for the engineering design.Therefore,it is necessary to conduct a more in-depth study on the vertical pull-out bearing characteristics of horizontal anchor plates.In this paper,through a self-made set of horizontal anchor plate visual pull-out test device,using scale model test,customized five kinds of aspect ratios（board width B=7.5cm,board length L=7.5cm,15 cm,22.5cm,30 cm,37.5 cm）anchor plate,each group has carried out four burying depth ratios（H/B=1/2/4/8）under a total of 20 working conditions,and the corresponding load-displacement curve is obtained,and the buried depth is analyzed.The influence of depth ratio and aspect ratio on the ultimate pull-out bearing capacity of anchor plates.Identify the displacement and deformation field of the soil around the anchor based on digital photographic measurement technology,and analyze the bearing mechanism.It can be obtained from the test that the bearing capacity per unit area of the anchor plate increases with the buried depth ratio,but does not show a linear growth relationship;when the buried depth is 1D,2D,4D,the ratio of the ultimate bearing capacity to the area of the anchor plate increases with the increase in the buried depth.The width ratio increases and decreases;when the buried depth is 8D,the aspect ratio has little effect on its ratio;under the premise of determining the buried depth and the board width,increasing the length of the anchor plate will almost no effect.The finite element analysis software ABAQUS is used to carry out the numerical simulation of the vertical drawing of the horizontal anchor plate,and the influence of the buried depth ratio and the length-to-width ratio on the sliding surface of the anchor plate in different directions is analyzed based on the equivalent plastic deformation cloud diagram.The results show that under this simulation condition,the plastic zone area surrounded by the sliding surface and the anchor plate and the ground in the plane of the anchor plate length and width direction symmetry plane increases linearly with the increase of the buried depth ratio;when H/B<5,The height of the sliding surface in the plane of the symmetry plane in the length and width direction also increases linearly with the buried depth ratio.If you continue to increase the aspect ratio,the height of the sliding surface hardly increases,and its size is determined by the plate width.And the height of the sliding surface on the long side of the board is determined by the board width.Therefore,for a rectangular anchor plate,the width of the plate determines the height of the sliding surface,and the area of the sliding surface on the long side of the plate increases linearly with the aspect ratio;the shape of the sliding surface in the horizontal plane of different depths can be the length,width and quarter of the anchor plate.The arcs are combined for description.For the same anchor plate to increase the buried depth ratio,the sliding surface of the soil around the anchor extends from a straight line to the ground surface and gradually develops into a curved shape that shrinks toward the center of the anchor plate,and finally forms a closed sliding surface inside the soil below the ground surface.Based on the analysis of the bearing mechanism of the vertical pull-out of the horizontal anchor plate,this paper proposes a logarithmic spiral morphology function that can describe the continuous evolution of the soil sliding surface around the anchor under the limit pull-out with the buried depth ratio,and establishes that there is no need to distinguish between shallow buried and deep buried The ultimate load-bearing unified mechanical model.According to the relative size of the anchor plate buried depth,the distance between the intersection of the sliding surface and the anchor plate,and the distance from the corresponding point to the anchor plate when the tangent line on the sliding surface is a vertical line,the limit equilibrium equation is established in three cases,and the horizontal bar is derived.A unified calculation method for the calculation of the ultimate bearing capacity of the vertical pull-out of the shaped anchor plate.The results show that: the new mechanical model well reflects the continuous change law of the damage characteristics of the soil around the anchor with the buried depth ratio,and there is no need to artificially distinguish between shallow and deep buried.In the calculation and analysis of 5 test cases,the calculation effect of the unified calculation method method ranked second among a total of 9 methods,showing strong adaptability.By summarizing the vertical pull-out bearing mechanism of the horizontal strip anchor plate,this paper proposes a logarithmic spiral morphology function that can describe the continuous evolution of the soil sliding surface around the anchor under the limit pull-out with the buried depth ratio.The unified mechanical model of ultimate load-bearing for shallow and deep burying.According to the relative size of the anchor plate buried depth,the distance between the intersection of the sliding surface and the anchor plate,and the distance from the corresponding point to the anchor plate when the tangent line on the sliding surface is a vertical line,the limit equilibrium equation is established in three cases,and the horizontal bar is derived.A unified calculation method for the calculation of the vertical pull-out ultimate bearing capacity of the shaped anchor plate.The results show that: the new mechanical model well reflects the continuous change law of the damage characteristics of the soil around the anchor with the burial depth ratio,and there is no need to artificially distinguish between shallow burial and deep burial.In the calculation and analysis of5 test cases,the calculation effect of the unified calculation method method ranked second among a total of 9 methods,showing strong adaptability.Based on the above-mentioned strip-shaped slab drawing load-bearing theory,considering the influence of the aspect ratio on the bearing capacity,observe the shape of the sliding surface in the Z direction,and simplify the sliding surface into a model that can be calculated by differentiating and integrating.The sliding surface can be combined.It is divided into three parts,and the bearing capacity is calculated separately.A unified mechanical model for the ultimate bearing capacity of a three-dimensional rectangular anchor plate without the need to distinguish between shallow and deep buried is also established.Also based on the buried depth of the anchor plate,the distance between the sliding surface and the anchor plate,and the tangent line on the sliding surface are When the vertical line corresponds to the relative size of the distance between the point and the anchor plate,the limit equilibrium equation is established in three cases,and a unified calculation method for the calculation of the vertical pull-out ultimate bearing capacity of the horizontal rectangular anchor plate is derived.The results show that: the new three-dimensional mechanical model well reflects the continuous change of the damage characteristics of the soil around the anchor with the burial depth ratio,and there is no need to artificially distinguish between shallow burial and deep burial.In the calculation and analysis of 4 test cases and 8 working conditions,the calculation effect of the unified calculation method method ranks second among a total of 5 methods,showing strong adaptability. |
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