青草沙水源地原水工程输水隧道单层衬砌管片接头荷载试验研究

Load tests on segment joints of single lining structure of shield tunnel in Qingcaosha Water Conveyance Project

纵缝转角刚度、纵缝(环缝)剪切刚度和弯矩传递系数是盾构隧道衬砌结构计算模型中的关键参数,历来是本领域研究的重点和热点。结合青草沙水源地原水工程,通过管片接头原型荷载试验,对上述关键计算参数进行研究。试验结果表明正弯矩作用下接头转角刚度符合双直线模型,负弯矩作用下转角刚度近似成线性,而且不同的接头构造情况下纵缝转角刚度值和其变化规律不同。在纵缝和环缝剪切试验中,管片间的错动随荷载变化过程分为3个阶段,其中错动主要发生在第二阶段。弯矩传递试验表明弯矩传递系数随着荷载的增大而减小。并且当纵缝转角刚度较大时,弯矩传递系数较小,反之亦然。最后结合试验结果,给出了盾构隧道衬砌结构计算模型关键参数具体取值范围和一些有益的结论,以供盾构隧道衬砌结构设计计算参考。

The key parameters for models of lining structure of shield tunnels,such as bending stiffness of radial joints,shear stiffness of radial（circumferential） joints and moment transfer coefficient,have always been the research focus in this field.The above key parameters are studied by means of the prototype load tests on segment joints in Qingcaosha Water Conveyance Project.The test results indicate that under sagging moments the bending stiffness coincides with the bilinear model,and under hogging moments it is similar to the linear model.The bending stiffness of radial joint and its variation law are different from those of various joint structures.According to the results from shear tests the dislocation change process of radial（circumferential） joint can be divided into three stages.The dislocation occurs mainly at the second stage.The results of moment transfer tests indicate that the moment transfer coefficient decreases with the increase of load.The greater the bending stiffness of radial joint is,the less the moment transfer coefficient is,and vice versa.Finally,based on the test results,the value range of the key parameters for the models of lining structure of shield tunnels is put forward.Several beneficial conclusions for the design of lining structure of shield tunnels are drawn.