不同埋深砂土盾构隧道掘进开挖面前方土拱效应研究

发布时间：2018-06-08 11:28

本文选题：土拱效应 + 不同埋深　；参考：《岩土力学》2017年10期

【摘要】：盾构施工过程中,开挖面前方土拱效应与掌子面盾构机推力大小和埋深密切相关。通过室内模型试验,研究不同砂土密度和不同隧道埋深条件下,盾构开挖面前方土拱效应,分析了砂土颗粒位移变化模式和土拱发展的时变特征,并揭示了不同埋深下土拱的发展规律和对失稳破坏机制的影响;同时基于室内模型试验,采用颗粒流程序进行模拟,从细观角度进一步研究了土拱效应。结果表明:不同埋深条件下,土拱发展规律一致且与支护力大小,地表沉降密切相关;低密度时土体破坏模式呈漏斗状,高密度为条带状,且土拱范围随埋深比增大而增大;颗粒流模拟得到不同埋深条件下,颗粒接触力、孔隙率和平均土压力变化规律一致。最后得出室内试验和PFC~(2D)颗粒流模拟得到的土拱效应相似的结论。
[Abstract]:During shield construction, soil arch effect in front of excavating face is closely related to thrust and depth of shield machine. The soil arch effect in front of shield excavation surface under different sand density and different tunnel depth is studied through indoor model tests. The variation model of sand particle displacement and the time-varying characteristics of soil arch development are analyzed. The development law of soil arch under different buried depth and its influence on the failure mechanism of soil arch are revealed, and the soil arch effect is further studied from the view of meso based on the indoor model test and the particle flow program. The results show that under different buried depth conditions, the development of soil arch is consistent and closely related to the support force and surface subsidence, the failure mode of soil is funnel-shaped at low density, the high density is strip, and the range of soil arch increases with the increase of buried depth ratio. The particle flow simulation shows that the particle contact force, porosity and average earth pressure are consistent with each other under different buried depths. At last, a conclusion is drawn that the soil arch effect is similar to that obtained from the simulation of PFC ~ (2 D) particle flow in laboratory.
【作者单位】：东南大学岩土工程研究所;
【基金】：国家自然科学基金项目(No.51578147)~~
【分类号】：U455.43

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