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针对翘起情况的裸露悬跨管道,建立考虑轴向力影响的刚性土壤支承的悬跨管道模型。利用小挠度梁理论,推导出脱离土壤的翘起段和悬跨段管道在自重作用下的变形和内力公式。以静弯曲挠度为振型函数,用能量法给出第1阶固有频率。对简支梁、固支梁和文本模型在含有轴向力情况下的静变形和第1阶振动频率进行了对比研究。研究表明:该文模型与考虑土壤变形的裸露悬跨管道的变形偏差不大,内力偏差很小。与现有规范推荐的简支梁和固支梁模型相比,该文模型更能反映裸露悬跨管道的实际情况。该文提供的介于简支梁和固支梁中间的新模型可简化裸露悬跨管道的内力和固有频率计算,弥补了现有推荐做法的不足。
Aiming at the bare suspended pipe in the case of cocking, a model of the suspended pipe supported by rigid soil considering the effect of axial force is established. Based on the theory of small deflection beams, the deformation and internal force formulas of the pipelines of the riser and the span of the suspended span under soil self-weight are deduced. Taking static bending deflection as mode shape function, the first order natural frequency is given by energy method. The static deformation and the first order vibration frequency of the simply supported beam, the fixed beam and the text model under axial force were compared. The results show that the deflection of the bare suspended pipe considering soil deformation is small and the internal force deviation is small. Compared with the simply supported beam and the fixed beam model recommended by the existing norms, this model can better reflect the actual situation of the exposed spanned pipe. The new model presented in this paper, which is intermediate between simply supported beams and fixed beams, simplifies the calculation of internal forces and natural frequencies of bare-spanned pipes, making up for the shortcomings of the current recommended practices.