锥形灌浆套管轴向承载力研究

RESEARCH ON AXIAL BEARING CAPACITY OF CONICAL GROUTED CONNECTION

为研究锥形灌浆套管轴向承载力性能,开展锥形灌浆套管的轴压试验。试验发现：锥形套管在轴向受压时,灌浆体在套管竖直方向上产生数条裂纹;随着荷载加大,裂纹不断发展直至贯通,灌浆体被分割成多个长方体块。在加载初始阶段锥形灌浆套管的剪应力-位移关系为线性,当轴力继续增大时,由于钢套管的环向拉应力已经超过钢材的屈服强度,剪应力-位移曲线进入塑性阶段,在套管最终丧失承载力前仍具有较大的变形能力。采用脆性开裂模型（brittle cracking）对锥形灌浆套管的轴压过程进行数值模拟,计算得到的裂缝开裂过程、破坏形态以及承载力曲线与试验结果吻合。

This paper investigates the conical grouted connections＇ axial bearing capacity by carrying out axialcompression test of the specimen.The results of test show that several cracks are produced in the grout in the verticaldirection of the steel pipe when the conical grouted connections are under axial compression.As the load increases,thecracks develop continuously until the grout is coalesced and the grout is divided into a plurality of rectangular blocks.Atthe early stage of loading,the shear stress-displacement curves are linear.With increasing of the load,thecircumferential tensile stress of the steel pipe has exceeded the yield strength of the steel,and the shear stressdisplacement curve has entered into the plastic phase.The ductile deformation capacity of the conical grouted connectionis still larger before the specimen loss the bearing capacity.A numerical model is established by using Brittle CrackingModel to simulate the axial compression process of the conical grouted connection,and the simulation results,includingthe cracks,failure mode,and loading response,are basically consistent with test＇s result.