Modeling and Accelerated Testing of Cured-In-Place Plastic Sewer Rehabilitation Liners

就地固化塑料(CIPP)管道衬里最近被用于修复破损的下水道管道。这种衬里通常安装在地下水位以下，因此会受到外部压力，这可能会导致主管道内的衬里因蠕变而屈曲。对这种屈曲现象的了解不足被认为是技术的限制，也是更具成本效益的下水道修复的障碍。为了解决这一问题，将开展实验和分析相结合的研究计划。试验计划将包括衬里材料的室温和高温材料特性试验，以及在相同温度下衬里的蠕变-屈曲试验。随着温度的升高，这种材料的软化将被用来建立时间和温度之间的关系，以便在方便的时间尺度上进行的测试可以延长到几十年。分析程序将检查屈曲问题的封闭形式解，并将涉及大量的有限元和线性屈曲的统计建模。将评估衬里屈曲时间随外部压力和衬里/主管几何参数的统计变化，以确定衬里系统在预期设计寿命内存活的概率。这项研究计划将为塑料下水道修复衬里的长期测试建立一种新的方法，并将突出必须考虑的因素，以开发基于物理的模型来预测CIPP衬里在50年服役期间的屈曲。*

Cured-In-Place Plastic (CIPP) pipe liners have recently been employed to rehabilitate deteriorated sewer lines. Such liners are often installed below the water table and are consequently subjected to external pressure which may lead to creep-induced buckling of the liner within the host pipe. Insufficient understanding of this buckling phenomenon is regarded as a limitation of the technology and a barrier to more cost effective sewer rehabilitation. To address this problem, coupled experimental and analytical research programs will be undertaken. The experimental program will involve room temperature and elevated temperature material characterization tests of liner materials as well as creep-buckling tests of liners at these same temperatures. The softening of this material with increasing temperature will be used to establish a relationship between time and temperature such that tests performed on convenient time scales can be extended to decades. The analytical program will examine closed form solutions to the buckling problem and will involve an extensive amount of finite element and statistical modeling of liner buckling. The statistical variation of liner buckling times as a function of the external pressure and liner/host pipe geometry parameters will be assessed to determine the probability that a liner system will survive for the desired design life. This research program will establish a new methodology for the long-term testing of plastic sewer rehabilitation liners and will highlight the factors which must be considered to develop a physically based model to predict buckling of CIPP liners over a 50+ year service period.***