纵向接头是预制综合管廊最薄弱部位,在外力和地基沉降作用下极易破坏,研究黏土地基预制综合管廊承插接头的受力性能,可为管廊接头或结构安全评价提供重要参考.以包头市新都市区地下综合管廊项目为研究背景,通过剪切模型试验探究了在剪切作用下预制综合管廊接头破坏特征及变形规律,揭示了综合管廊接头各部件的受力特性及工作机理.研究结果表明:管廊承口最先出现水平裂缝,随着竖向加载位移的增大,承口依次出现水平裂缝-斜裂缝-径向裂缝,当加载位移达到28 m m时,承口发生混凝土剥落,插口混凝土出现拉裂;接头顶板、底板向舱内变形,侧墙向外凸起,大舱室变形高于小舱室;高强螺栓应力最大提升了0.382GPa,伸长量达到2.6mm,螺栓在加载过程中受到拉-弯-剪共同作用;管节受力分为3个阶段,地基、接头混凝土、高强螺栓逐步参与到接头抗剪过程中,第2、第3阶段接头剪切刚度分别下降了73％ 和57.9％.预制综合管廊接头承口,尤其在倒角位置应进行局部加强,高强螺栓应尽早参与接头抗剪,防止承插接头提前破坏.
Shear Behavior of Socket Joints of Prefabricated Utility Tunnel with High-strength Bolts
The longitudinal joint is the weakest part of the prefabricated utility tunnel and is easily damaged under external force and foundation settlement. The mechanical performance of the socket joints of the prefabricated utility tunnel on a clay foundation is essential to the safety evaluation of the utility tunnel joint or structure.Based on the utility tunnel project in the Xindu District of Baotou City,the failure characteristics and deformation rules of prefabricated utility tunnel joints under shear action were investigated using the shear model test.The mechanical characteristics and working mechanism of all components of utility tunnel joints were revealed. The results showed that the horizontal cracks first appeared at the hub of the utility tunnel.As the vertical loading displacement increased,oblique and radial cracks successively appeared horizontally.When the loading displacement reached 28 mm,the concrete was broken off at the hub,and tensile cracks appeared at the concrete at the socket.The top and bottom plate of joints within the cabin were deformed,and the side wall bulged.The deformation of the large cabin was higher than that of the small cabin.The maximum stress of the high-strength bolts was increased by 0.382 GPa and the elongation reached 2.6 mm.The bolt was subjected to the combined action of tension-bending-shear during loading. The stress of the tunnel joint was divided into three stages.The foundation,joint concrete,and high-strength bolts are gradually involved in the shear process of the joint. The shear stiffness of the joints in the second and third stages decreased by 73％ and 57.9％,respectively. The joint hub of prefabricated utility tunnel,particularly at the tapered edge,should be locally reinforced. High-strength bolts should be incorporated as early as possible to prevent premature failure of the socket joint.
万方数据
维普
