Abstract:

Soil collapse in natural disasters seriously threatens to the stability of buried pipelines. In order to study the stability of buried pipelines in the suspended collapse area, based on the finite element method,the displacement, strain and stress of buried elbows with different wall thickness and outer diameter in the suspended state were studied. Based on the eigenvalue buckling theory, the ultimate length that the buried elbow can withstand when the soil collapses under certain conditions was studied. The results show that reducing the buried depth, increasing the outer diameter and wall thickness can effectively reduce the displacement of pipeline in soil collapse. The stress and strain of the pipeline occur in the center of the collapse area and the fixed ends of the two sides; the increase of the outer diameter and wall thickness of the pipeline can inhibit the occurrence of local excessive stress to a certain extent. The ultimate length of the buried elbow in the goaf is about 87 m, and improving the outer diameter and wall thickness of the pipeline can enhance the buckling resistance of the buried elbow in the process of soil collapse.

Key words: Soil collapse, Buried elbow, Finite element, Buckling eigenvalue

摘要：

自然灾害中的土体塌陷严重威胁埋地管道的稳定性。为了研究埋地管道在悬空塌陷区的稳定性，基于有限元方法，研究了壁厚、外径不同的埋地弯管在悬空状态下的位移、应变和应力；采用特征值屈曲理论，研究了一定条件下埋地弯管在土体塌陷时所能承受的极限长度。结果表明，减小管道在土体中的埋深、增大管道外径以及壁厚，可以有效降低管道在土体塌陷过程中的位移，管道的应力和应变均发生在塌陷区的中心和两侧固支端的位置；管道外径、壁厚的提高，可以在一定程度上抑制局部应力过高；埋地弯管在采空区的极限长度约为87 m，并且增大管道外径和壁厚可增强埋地弯管在土体塌陷过程中的抗屈曲能力。

关键词: 土体塌陷, 埋地弯管, 有限元, 屈曲特征值