Model experimental study on deformation mechanism of micro piles and oil-gas pipelines in mountain slopes
MA Yanjun1，2，WU Honggang2，QIN Changle1，PANG Jun1，CHEN Qing1，XU Wenhan3
(1. School of Civil Engineering，Lanzhou Jiaotong University，Lanzhou，Gansu 730070，China；2. China Railway Northwest Science Research Institute Co.，Ltd.，Lanzhou，Gansu 730070，China；3. School of Civil Engineering and Architecture，Southwest University of Science and Technology，Mianyang，Sichuan 621000，China)
Abstract：To investigate the interaction mechanisms and failure evolution processes of landslide-pipeline systems under different forms of micro-pile reinforcement，large-scale indoor model tests were conducted using grouting conventional piles and grouting flower tube piles for slope protection in the Southwest mountainous region，with a focus on the emergency rescue project of a natural gas pipeline landslide. Strain gauges，soil pressure sensors and dial gauges were used to monitor the corresponding indicators of the structural elements within the landslide system，and analysis was performed on the data of pile bending moments，soil pressures and pile head displacements. The results showed that the system consisting of piles，sliding masses and pipelines in the landslide exhibited coordinated changes during the development of the landslide，with deformation occurring in four stages：initial stage，uniform deformation stage，rapid deformation stage and failure stage. Micro-piles primarily experienced bending and shear failure near the sliding belt. Near the sliding belt，the soil pressure in front of the piles reached its maximum value，and the flower tube piles exhibited a rotational trend with the sliding belt as the axis，resulting in significant soil pressures at the pile base. The magnitude of bending moments exhibited an overall“S-shaped”curve distribution，and due to the interaction with the pile cap，larger bending moments were generated in the upper part of the piles. The pile-soil composite structure formed by grouting on one side of the flower tube piles better resisted the landslide thrust. Even after the piles reached their ultimate strength and failed，the composite structure still provided a certain degree of resistance against sliding. Through multidimensional integrated data analysis，it was observed that the deformation of the pipeline occurred later，providing a time window for emergency rescue work. The pipeline mainly experienced bending failure and compression failure，with the interface position being the weak point in pipeline protection. Micro-piles have significant potential for applications in the protection of oil and gas pipelines in mountainous regions，and further research and improvement play a positive role in the application of micro-piles in landslide control.
马彦军1，2，吴红刚2，秦昌乐1，庞 军1，谌 清1，徐汶瀚3. 山区斜坡中微型桩及油气管道变形机制模型试验研究[J]. 岩石力学与工程学报, 2024, 43(3): 728-741.
MA Yanjun1，2，WU Honggang2，QIN Changle1，PANG Jun1，CHEN Qing1，XU Wenhan3. Model experimental study on deformation mechanism of micro piles and oil-gas pipelines in mountain slopes. , 2024, 43(3): 728-741.
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2024, Vol. 43 
