不同滑坡形式下埋地管的纵向受力分析

Longitudinal Stress Analysis of Pipeline Buried in Two Different Forms of Landslide

滑坡变形带中的埋地排水管一旦开裂破坏,管道中的水将直接渗入坡体中,使坡体变形加速而破坏,因此,在进行滑坡变形带中埋地管的设计时必须考虑坡体变形对管道的影响。本文讨论牵引式滑坡和推移式滑坡两种不同形式下埋地管的纵向受力和变形特性,在一定的假设条件下,推导得出两种形式滑坡中管道的弯矩、剪力、位移以及最大应力。工程实例验证表明:由于推移式滑坡中的管道有被动土压力作支撑,在相同外力作用下,推移式滑坡中的管道应力明显高于牵引式滑坡中的管道;如果在滑坡变形带中采用PVC管,因其纵向伸长率较大,变形控制条件比较容易得到满足,需将强度指标作为设计考虑的主要因素,对最大应力超过管道许用应力的可采取更换强度较高的管材或增加管道壁厚的方法来达到强度要求。

Once the buried drainage pipeline in landslide zone cracks, the water in the pipeline will directly infiltrate into the slope, causing the acceleration of slope deformation which will lead to the slope destruction, therefore the influence of the slope deformation on the pipeline must be taken into consideration when we design the buried drainage pipeline in the landslide zone. The longitudinal stresses and the deformation characteristics of buried pipeline in the pull-type landslide and the push-type landslide are discussed. Under certain assumed conditions, the bending moment, shear force, displacement and maximum stress of the pipeline are derived. The result of an engineering example shows that： under an external force, the stress states of the pipeline in the push-type landslide are superior to that in the pull-type landslide due to the support of passive earth pressure to the pipeline in the push- type landslide. If polyvinyl chloride （ PVC ） pipes are used in landslide zone, the deformation control criteria can easily get satisfied owing to the large longitudinal elongation of PVC pipes, the strength control criteria should be taken as the major factor in design. And if the maximum stress in the pipeline exceeds the allowable stress, a pipeline with higher strength or greater wall thickness can be taken as the substitute in order to meet the strength requirements.