管子作为简支梁的弯曲试验地下管道由于地基不均匀、土壤沉陷等会发生横向弯曲~*。为了防止管中出现横向裂缝,环断面上的预压应力应不小于1.5公斤力/厘米~2。表2是振动挤压管管径与纵筋根数的关系。三阶段预应力管在缠绕环筋时管壁承受最大的荷载,而振动挤压管当环筋放张时,压力沿整个管长同时传递,因此,产生较小的轴向拉力。但在振动挤压管中有约20厘米 The pipe is used as a simple test for the bending test of underground pipes due to non-uniform ground, soil subsidence, etc. lateral bending occurs. In order to prevent transverse cracks in the pipe, the pre-stress on the ring section should not be less than 1.5 kgf/cm2. Table 2 shows the relationship between the diameter of the vibrating tube and the number of longitudinal bars. The three-stage prestressed pipe bears the maximum load when winding the ring ribs, and the vibrating extruding pipe transmits the pressure along the entire pipe length when the ring ribs are stretched. Therefore, a smaller axial tension is generated. But about 20 cm in the vibrating squeeze tube