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研发了一套足尺浅埋管道上拔试验装置,针对不同软土强度、管道埋深和加载方式的情况,较系统地研究了上拔过程中管-土相互作用、管周软土破坏模式、上浮承载力及其影响因素。试验结果表明:在管道上拔过程中,回填软土的变形主要由土块相对位置调整及块间间隙水的排出产生,这与均质软土中变形主要由固结导致明显不同;埋深管径比H/D(28)1时,回填软土的破坏模式接近流动破坏,远小于规范建议的H/D≥3;H/D≥1时,建议采用Palmer方法计算长期荷载作用下回填软土的极限上浮承载力;H/D越大,则回填软土中管道的上浮承载力也越大;在其他条件一定时,回填软土中管道的上浮承载力基本随抗剪强度呈线性增长,由于地基固结速度明显较均质软土快,设计时可适当考虑土体强度恢复的影响。
A set of full-scale shallow-buried pipeline pull-up test equipment was developed. According to the different soft soil strength, pipeline depth and loading method, the relationship between tube-soil interaction, , Floating capacity and its influencing factors. The results show that the deformation of backfill soft soil is mainly caused by the relative position of soil blocks and the discharge of interstitial water during the process of pipeline pull-up, which is obviously different from the deformation caused by consolidation in homogeneous soft soil. The depth When the diameter ratio H / D (28) 1, the failure mode of backfill soft soil is close to the flow failure, far less than the recommended H / D≥3; when H / D≥1, it is recommended to calculate the backfill under long- When the H / D is larger, the upward floating capacity of the pipeline in soft soil under backfill is also larger. When the other conditions are certain, the upward carrying capacity of the pipeline in soft soil under reclamation increases linearly with the shear strength , Due to the consolidation rate of foundation is obviously faster than that of homogeneous soft soil, the influence of soil strength restoration may be properly considered in the design.