PCCP砂浆保护层强度取值及开裂控制条件的研究和探讨

Research on Strength and Cracking Control of Mortar Coating in PCCP

分析了中美两国PCCP设计标准中关于砂浆强度取值以及开裂控制条件的一些规定,并基于ABAQUS有限元分析软件,模拟和研究了PCCP在安装和运行过程中砂浆保护层的力学响应机理,依据计算结果对设计标准中存在的问题进行了探讨。结果表明,目前设计中采用砂浆的抗压强度作为砂浆强度的设计值,高估了PCCP砂浆的承载能力,同时,设计标准中控制砂浆层开裂验算中的应变限值过高,导致砂浆保护层容易产生裂缝这一现象被忽视,容易导致由设计缺陷造成的PCCP结构失效和破坏。

The strength and cracking control strain limits of mortaring coating in PCCP in both AWWA standard and Chinese specification were discussed and the structural behavior analysis of mortar coating was conducted based on the ABAQUS FEM software. The comparison of simulation results and design standard shows the strength of mortar in the present design overestimates the capability of mortar coating in PCCP, as well as the strain limits of cracking control are too high so that some crackings are usually neglected. Therefore, the structural failure of PCCP caused by design defect might happen.