预应力钢筒混凝土管极限内压与损伤机理研究

Investigation on Ultimate Internal Pressure and Damage Mechanism of PCCP

通过建立运行期管线及其周围土体的非线性有限元模型,研究了预应力钢筒混凝土管(PCCP)在极限内压荷载下的损伤演化规律。结果表明:管线在工作压力及设计压力荷载下均可安全运行;随内水压力的进一步增加,管芯由受压转变为受拉状态,进而出现(微)裂缝损伤,且材料损伤先在管芯内侧出现,管芯损伤后钢筒应力迅速增加直至达到其屈服强度,达到弹性极限状态;在极限内压下埋地管线内外层材料失效位置不同,但材料损伤均由插口端向管体中部延伸。研究成果可为遭受水锤作用PCCP管线的损伤评价提供参考。

The nonlinear finite element model of pipeline was established including its surrounding soil,then the material damage and damage mechanism of the pipeline under the limit internal pressure load were analyzed.The results show that the pipe can operate safely under the working internal pressure and the design pressure in both cases.With increasing of internal water pressure,the concrete core transforms into tension state,and then(micro)crack damage in inner side occurrs first.Due to the material damage of the pipe core,the stress of the steel cylinder increases rapidly until it reaches its yield strength.The damage position of each material is different under the combined loads,however,the damage is both extended from the spigot end to the middle of the pipe.The finding can provide a reference and suggestions for damage assessment of in-service PCCP.