线弹性土壤中埋设悬跨管道的弯曲和振动特性

利用细长梁小挠度理论,研究给出了两端埋设在线弹性土壤中的悬跨段管道和埋设段管道在自重作用下的变形和内力公式。基于静挠度公式,用能量法给出了第一阶弯曲振动的固有频率公式。讨论了不同土壤刚度条件下悬跨段管道的变形和内力特征,以及第一阶弯曲振动固有频率,并和工程上推荐使用的简支梁和两端固支梁的静动态特性进行比较。研究表明在跨度大、土壤刚度大、管道弯曲刚度较小时无量纲土壤刚度系数较大,埋设段管道对悬跨段管道的刚度约束比较大,悬跨段管道可以近似按两端固支梁模型来模拟;反之,只有在土壤刚度系数较小的几个参数点上,悬跨管道的静动力特性等价于简支梁模型。

Bending and vibration characteristics of spanning pipe buried in linear elastic soil

Deflection and internal forces formulae of buried section pipe in linear elastic soil and spanning section pipe under self-weight load are deduced with small deflection beam theory.The first order nature frequency formula of bending vibration is given by energy balance method based on the static deflection formula.Deflection and internal forces characteristics as well as the first order frequency of spanning pipe are discussed under different soil stiffness.Comparison between spanning pipeline and simply supported beam,and fixed-fixed supported beam model recommended in engineering in terms of static and dynamic characteristics is done.Research shows that the stiffness influence of the buried section pipe to the spanning section pipe becomes stronger when the span increases,or for the pipe with smaller flexural rigidity in harder soil whereas dimensionless soil stiffness coefficient increases,then the spanning pipe can be modeled by the fixed-fixed supported beam approximately.On the contrary,the spanning pipe can be modeled as a simply supported beam only on several special points with small soil stiffness coefficient.