埋地HDPE管道施工过程中装配应变分布规律的现场试验研究

Full-scale field tests on hoop strains of buried HDPE pipes during construction

现场测试数据表明HDPE双壁波纹管道在填土施工时会产生较大装配应力和应变。然而,目前关于HDPE管道服役期力学性能的研究和设计方法均忽略装配效应对管道力学特性的影响,高估了管道服役性能并带来安全隐患。通过现场试验,对管径600 mm HDPE双壁波纹管道填土施工过程中产生的径向挠度与管周环向应变进行实时监测;结果表明,管道施工填土产生的最大装配应变发生在管侧(与管轴线等深度的管壁处),而管顶和管侧挠度近似相等;管顶挠度与填土高度和最大管周环向应变之间均存在良好线性关系。通过有限元数值模拟分析并综合现场试验数据,提出了基于填土高度的管顶挠度预测公式和基于管顶挠度的最大管周环向应变预测公式,可以方便快捷地预测HDPE管道装配应变。通过对比报道的两个现场试验的实测数据验证所得公式,结果表明所得公式预测值与实测管顶挠度的误差范围为7%~13%,表明该公式可准确计算施工填土时HDPE管道的管顶挠度。

Field test data show that the installation of HDPE pipes results in considerable additional strain and stress on the pipes.However,it has not been well addressed in previous studies.In this study,the 0.6 m-diameter HDPE pipes are used in the field tests to investigate the relationship among the hoop strains,vertical and horizontal deflections and thickness of soil cover.It is found that the hoop strains generated in the construction phase(i.e.,installation of HDPE pipes) have a good linear relationship with the deflection and the thickness of soil cover.This finding is then validated by a series of finite element numerical simulations.Based on the FE analysis,an empirical relationship is proposed to predict the hoop strains on the HDPE pipes generated in the construction phase.The availability of the proposed method is validated by comparing the predicted values with the field measured ones reported in the previous studies.The results demonstrate that the proposed method has merits of satisfactory accuracy and easy use.