Pullout Capacity Of Plate Anchor In Sand By Laboratory Test

This paper on the anchor plate problem research status at home and abroad are summarized,and then conducts an indoor model test for the uplift bearing capacity of anchor plates in sand,considering that the anchor plates are under different embedding depths,different inclination angles and different shapes,The development of the surrounding soil failure surface during the pull-up of the anchor plate was analyzed.Based on this,the following researches are carried out on the uplift characteristics of anchor plates in sand:In this paper,laboratory tests were carried out in sand,and three types of anchor plates were studied under 6 groups of embedded depth respectively.It is found that the ultimate load of the anchor plate and its corresponding uplift displacement increase with the increase of the embedding depth.When the embedment ratio exceeds 4,the anchor plate is changed from shadow failure mode to deep failure mode,The ultimate uplift capacity of circular anchor plate is 20% higher than that of square anchor plate.The bearing area of anchor plate affects the bearing characteristics.The displacement-time curve of the anchor plate during the loading stage were studied,the anchor plate does not start to generate displacement until a certain load is applied,the displacement of the anchor plate is still increasing slowly during the loading phase.The displacement change rate of the anchor plate was the largest at about 1 minute after the load was applied,and the displacement of the anchor plate tended to be stable at about 2 minutes after the load was applied.Laboratory tests of circular anchors with 5 inclination angles at different embedment ratio were carried out,It is found that at the same embedment ratio,the smaller the inclination of the anchor plate,the greater the ultimate bearing capacity of the anchor plate,when the inclination of the anchor plate is the same,the greater the embedment ratio,the greater the ultimate bearing capacity of the anchor plate,but the deeper the embedding depth,the smaller the influence of the inclination on the ultimate bearing capacity.Laboratory tests of semicircular anchor plates at different embedding depths were carried out,the white sandy soil is used to mark the soil layer for every 5 cm filled in the model box,and the displacement path of the soil during the uplif process of the anchor plate is obtained,it is found that the anchor plate undergoes threestages: "elastic compression stage-elastoplastic stage-complete shear fracture stage".The rupture surface of the shallow embedding circular anchor develops from the edge of the anchor plate to the sand surface with a trumpet shape,the rupture surface of the deep embedding anchor plate is formed below the sand surface and is balloon-shaped.Based on the test,it is assumed that the failure surface of the shallow embedding circular anchor is inverted round platform.The angle between the failure surface and the vertical direction is 45°-?/2,the formula of ultimate bearing capacity of shallow embedding circular anchors were derived,and the calculated results are in good agreement with the experimental data.