高纵向应变下管道凹坑的评价方法

管道施工建设和服役期间发生的外部干扰经常会导致管道产生凹坑，在地面运动和地震活动区域，管道也会产生高纵向应变。在假定主要载荷为内压且纵向应变水平较低的情况下，开发并验证了目前的凹坑评价方法，凹坑在高纵向应变下的行为尚不清楚。讨论了由美国DOT（美国交通运输部）和PHMSA（美国管道与危险材料安全管理局）资助的关于高纵向应变下凹坑评价准则。通过参数数值分析，确定并研究了带凹坑管道中，控制压缩应变能力（CSC）的关键参数和原理。通过参数分析和全尺寸验证试验，制定了高纵向应变条件下带凹坑钢管的CSC评价方法。

Assessment of Dents under High Longitudinal Strain

External disturbances during the construction and service often lead to pits in the pipeline and the high longitudinal strain can happen in the area of the ground motion and seismic activity. Under the assumption that the main load is internal pressure and the longitudinal strain is low，the present method of the pit evaluation is developed and validated，but the behavior of the pits under the high longitudinal strain is unknown. This paper discusses the pits assessment under the high longitudinal strain funded by DOT (U.S. department of transportation) and PHMSA (U.S. pipeline and hazardous materials safety administration). Through the parameter numerical analysis，the key parameters and principles of the controlling compressive strain capacity(CSC) in the pipe with pits were determined and studied. Through the parameter analysis and the full-size verification test，the CSC assessment of the steel tubes with pits under the high longitudinal strain was developed.