Field Contrast Test And Numerical Simulation Study Of Anchor Pulling Capacity

The innovation of anchoring form is one of the important development directions of anchoring technology.In this paper,a barbed anchor is proposed for the application of anchoring structure in actual engineering.Three segments of steel are welded at an angle to the bottom of the ordinary anchor rod body to form an inverted thorn.The bearing capacity of the anchor rod is determined by the smaller value between the pull-out bearing capacity controlled by the bond strength of the soil and the tensile bearing capacity controlled by the strength of the rod body.The influence of the bite cooperation with the grouting body can improve the tensile bearing capacity of the rod body.Considering the complexity of the working conditions in the actual project and the exact impact of barbs on the anchor,the difference between the anchoring mechanism of barbed anchors and ordinary anchors is not clear,so it is necessary to carry out an in-depth study of barbed anchors.On the pull-up bearing mechanism.In this paper,a combination of on-site pull-out test and numerical simulation is used for ordinary anchor rods,anchor rods with different bar lengths,and different numbers of barbed bolts.The force failure mechanism and pull-out bearing capacity of barbed bolts are studied,and The effects of grouting parameters on ordinary anchors and barbed anchors are discussed.The main research results are as follows:(1)Through the pull test of 9 groups of on-site bolts,compare the length of the bolt and the number of barbs.The 3 # anchor with the expansion agent added to the grouting body has a pull-out bearing capacity of 60 kN,compared with the anchor of the same length.The anti-pull force of the bar has been significantly improved,but the anti-pull force of barbed anchors has not changed significantly,and the increase in the number of barbs has not significantly improved the anti-pull force.(2)The length of the anchor rod has a certain effect on the pullout force.The 1 #,2 #,and 4 # anchor rods are 5.5m in length and the maximum pull-out bearing capacity is 50 kN.The 9 # anchor rod is 8.5m in length and the maximum pull-out resistance.The pulling force reached 70 kN,and the displacement of the anchoring structure of the 9 # anchor under the same load was also less than the displacement of the shorter anchor under the same number of barbs,but the displacement of the anchoring structure with different numbers of barbs under the same anchor length did not change significantly.(3)By using ABAQUS to numerically simulate the 1 # to 4 # anchors,the axial force,strain and displacement distribution of the anchor body are obtained.The axial force is attenuated at the barbed area,and then partially recovered,and the overall internal stress of the anchoring structure is observed.Distribution,it can be seen that part of the axial force is transmitted to the grouting body through barbs and then transmitted to the lower rod body through the grouting body,and the axial force of the bottom anchor rod approaches 0,and the first group of barbs set at the bottom of the rod body is almost(4)The barbed anchor is different from ordinary anchors in the internal stress distribution of the anchoring structure.The effect of barbed on the axial force transmission does not involve the part outside the grouting body,but it does not affect the soil and grouting body.Side friction resistance.