摘要
山区天然气管道工程难免会遭遇滑坡等地质灾害的影响,这给穿越滑坡区域的沿线管道的安全运营造成严重威胁。文章以中贵天然气管道K558+700滑坡为工程背景,通过室内大型物理模型试验,研究对比花管微型桩与螺纹微型桩两种新型支挡结构在管道滑坡中的支护机理及适用性。试验表明:(1)花管微型桩山侧及河侧峰值土压力沿桩深分布形式基本相似,大体呈“S”曲线形,桩后土体土拱效应明显,且在各级荷载下分布形式大致保持一致,总体来说花管桩侧土压力分布规律为桩中最大,桩顶次之,桩底最小;滑带附近的桩体周围土压力较大,在抗滑桩设计工作中应重点考虑优化。(2)螺纹桩山侧峰值土压力沿桩深分布图大体呈双“S”曲线形,河侧峰值土压力相比山侧分布形式产生了较大差异,桩底的土压力相比山侧有很大幅度减小;随外部荷载的增加桩周土压力增加幅度较大,表明螺纹微型桩在横向承载性能方面有所欠缺。(3)花管桩桩身弯矩沿深度方向呈“M”形分布,桩身离模拟滑面以上5 cm位置处产生最大正弯矩;螺纹桩桩身弯矩分布沿深度方向呈“S”形,桩体正负弯矩位置在模拟滑面附近大致呈旋转对称分布,滑面以上大部分区段为负弯矩,滑面以下为正弯矩;在相同推力荷载工况下,螺纹微型桩变形程度大于花管微型桩。(4)在滑坡作用下花管微型桩可以有效减小传递到管道的坡体应力,在一定程度上预防管道受力破坏;而螺纹桩在较大横向荷载下抗弯性能不足,变形严重,破坏后不能有效承担滑坡推力,传递到桩前管道的应力较大,从而导致管道变形程度更为强烈。在本试验条件下,花管微型桩对管道的保护效益突出,更适用于作为管道—滑坡区域的支挡结构。
Natural gas pipeline projects in mountainous areas are inevitably affected by geological hazards such as landslides,which pose a serious threat to the safe operation of pipelines along the routes through landslide areas.Based on the engineering background of China-Guizhou natural gas pipeline K558+700 landslide,this paper studies and compares the supporting mechanism and applicability of two different support structures,namely,flower-tube micro-pile and threaded micro-pile,in pipeline landslide through indoor large-scale physical model tests.The results show that:(1)The distribution pattern of peak soil pressure along the mountain side and river side of flower tube micro-piles is basically similar along the pile depth,which is in the shape of"S"curve.The soil arching effect behind the pile is obvious,and the distribution pattern of soil pressure is generally consistent at all levels of load.In general,the distribution pattern of soil pressure on the side of the flower-pipe pile is the largest among piles,followed by the pile top,and the bottom of the pile.The soil pressure around the pile near the sliding zone is larger,so the optimization should be considered in the design of anti-slide pile.(2)The distribution diagram of the peak earth pressure along the pile depth of the threaded pile presents a double"S"curve.The distribution pattern of the peak earth pressure on the river side is significantly different from that of the mountain side,and the earth pressure at the bottom of the pile decreases greatly compared with that of the mountain side.With the increase of external load,the soil pressure around the pile increases greatly,indicating that the screw micro pile is deficient in lateral bearing capacity.(3)The bending moment of flowered pipe pile presents an"M"shape distribution along the depth direction,and the maximum positive bending moment occurs at the position 5 cm above the simulated slip surface.The pile body bending moment distribution along the depth direction is"S"shape,and the pile body positive and negative bending moment position near the simulated sliding surface roughly rotate symmetrical distribution,most of the region above the sliding surface is negative bending moment,the pile body below the sliding surface is positive bending moment.Under the same thrust load,the deformation degree of the screw micro pile is greater than that of the flower tube micro pile.(4)The load-bearing performance of the splined pipe pile is better than that of the threaded pile under thrust load,which effectively reduces the landslide thrust transferred to the pipeline;Under the large thrust load,the threaded pile can not effectively bear and offset the landslide thrust due to its insufficient flexural performance and serious deformation,and the stress transmitted to the pipe in front of the pile is large,causing more intense deformation of the pipe.Under the condition of this test,the flowered pipe micro-pile has outstanding protection benefit to the pipeline,and is more suitable for the retaining structure of the landslide area of the pipeline.
作者
高建章
方迎潮
王学军
葛华
沈茂丁
梁栋
孟建
GAO Jianzhang;FANG Yingchao;WANG Xuejun;GE Hua;SHEN Maoding;LIANG Dong;MENG Jian(Pipe China Southwest Pipeline Co.Ltd.,Chengdu,Sichuan 610041,China;Key Laboratory of Mountain Hazards and Earth Surface Process,Chinese Academy of Sciences,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences&Ministry of Water Conservancy,Chengdu,Sichuan 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China;China Petroleum Pipeline Engineering Co.Ltd.,Langfang,Hebei 610036,China)
出处
《中国地质灾害与防治学报》
CSCD
2023年第2期120-131,共12页
The Chinese Journal of Geological Hazard and Control
基金
国家管网集团西南管道有限责任公司科技项目(2020B-3106-0501)
国家管网集团科技项目(WZXGL202106)。
关键词
滑坡
天然气管道
花管微型桩
螺纹微型桩
支护机理
landslide
natural gas pipeline
flower tube micro pile
micro thread pile
the supporting mechanism