沟槽回填泡沫轻质土管道应力与压力分析

Research on Stress and Pressure around the Pipe with Trench Backfill of Foamed Lightweight Soil

采用泡沫轻质土替代常规散粒体材料进行城市管道沟槽回填尚处于尝试探索阶段,其管周压力分布特征是相关设计的关键技术问题。基于现场试验获得了路面结构层填筑过程中沟槽回填泡沫轻质土柔性管道的表面应力分布规律,并将其应用于数值分析模型验证。采用验证后的模型,分析管周压力分布特征并与适用于散体回填材料的Iowa模型进行对比。结果表明:HDPE管道表面应力随沟槽上方结构层的填筑厚度增加不断增大,管顶和管侧最大实测应力分别达到了146.4kPa、152.1kPa;管周压力近似呈圆形分布,上部略小于下部;泡沫轻质土回填区中的柔性管道,在水平、竖直方向上的压力均沿管径呈抛物线分布,其分布范围比Iowa模型大。

It is still at the stage of exploration to replace the conventional granular material with foamed lightweight soil for trench backfill of municipal pipeline.The characteristics of pressure distribution around the pipe are the key technical problems for its design.Based on the field test,the surface stress distribution rules on the flexible pipe in trench backfill foamed lightweight soil are obtained during the construction process of pavement structure,which are applied to the validation of the numerical analysis model.The verified numerical model is used to analyze the characteristics of the pressure distribution around the pipe and compared with the Iowa model which is suitable for granular backfill materials.The results show that the surface stress of HDPE pipe increases with the filling of the structural layer above the trench,and the maximum measured stress of the pipe top and the pipe side reaches 146.4kPa and 152.1kPa respectively.The pressure around pipe is approximately in circular distribution,which is slightly smaller at the upper than that at the lower part.The pressure in horizontal and vertical direction for the flexible pipe in the backfill of foamed lightweight soil are parabolic distributed along the pipe diameter,and its distribution range is larger than that in Iowa model.