装配式地连墙接缝变形特性研究

Research on joint deformation characteristics of prefabricated diaphragm walls

为了研究接缝对装配式地连墙变形特性的影响并采取合理的改进措施,采用现场试验的方法将局部现浇地连墙替换为装配式地连墙,并对其实测的变形数据进行了对比分析;在实测数据分析的基础上,通过PLAXIS2D有限元软件模拟分析了不同深度横向接缝对装配式地连墙变形特性的影响规律;通过PLAXIS3D有限元软件对比了现浇墙与装配式地连墙水平方向及竖直方向变形形态,分析了竖向接缝对装配式地连墙变形特性的影响规律;最后,针对实测数据显示出的变形偏大问题,提出了改变冠梁刚度、围檩刚度、墙幅宽度、支撑位置4种改进措施,并通过PLAXIS3D有限元软件进行了验证。结果表明:装配式地连墙的接缝对墙体的刚度存在弱化作用,增大了其变形程度;位于坑底以上的横向接头失效时,墙体水平位移会显著增大,位于坑底以下的横向接头失效时,不会引起墙体水平位移的显著增大;竖向接头会显著减小装配式墙体的整体刚度,使其协同变形能力变差,变形更加难以控制;适当调节支撑位置可有效缓解墙幅间的错动和减小墙体变形。

In order to study the influence of joints on the deformation characteristics of prefabricated diaphragm wall and take reasonable improvement measures,the cast-in-place wall was replaced by prefabricated diaphragm wall by field test method,and the measured deformation data were compared and analyzed.Based on the analysis of measured data,PLAXIS2D finite element software was used to simulate and analyze the influence of transverse joints at different depths on the deformation characteristics of prefabricated diaphragm walls.PLAXIS3D finite element software was used to compare the horizontal and vertical deformation patterns of cast-in-place wall and prefabricated diaphragm wall,and the influence of vertical joints on the deformation characteristics of prefabricated diaphragm wall was analyzed.Finally,aiming at the problem of large deformation shown by the measured data,four improvement measures were proposed to change the stiffness of crown beam,the stiffness of enclosing purlin,the width of wall,and the support position,which were verified by the finite element software PLAXIS3D.The results show that the joints of prefabricated diaphragm walls weaken the stiffness of wall and increase the deformation degree.When the transverse joint above the bottom of the pit fails,the horizontal displacement of the wall will increase significantly,while when the transverse joint below the bottom of the pit fails,the horizontal displacement of the wall will not increase significantly.The vertical joint will significantly reduce the overall stiffness of the prefabricated diaphragm walls,making its collaborative deformation capacity worse and deformation more difficult to control.Properly adjusting the support position can effectively alleviate the dislocation between the wall and reduce the deformation of the wall.