| 摘要: |
| 【目的】研究不同级别围岩中软弱夹层对地下洞室围岩稳定性以及支护结构安全性的影响。【方法】利用奥地利大型岩土工程分析系统FINAL，通过建立软弱夹层分布于地下洞室拱顶、肩部以及侧墙时的不同有限元分析模型，分析不同级别（Ⅱ、Ⅲ、Ⅳ级）围岩下软弱夹层对地下洞室围岩位移场、应力场、塑性区及喷层应力的影响。【结果】Ⅱ、Ⅲ级围岩中，顶拱软弱夹层使拱顶位移增加约85%，侧墙位移减小30%～35%；Ⅳ级围岩中，拱顶位移增加约120%，侧墙位移增加约10%；各级围岩中，顶拱软弱夹层使围岩拉应力区面积增大4.0～5.0倍；Ⅱ、Ⅳ级围岩中，拱顶软弱夹层对围岩塑性区的影响较小，Ⅲ级围岩中塑性区面积约为无软弱夹层时的2.0倍。【结论】分布在不同级别围岩中，不同位置软弱夹层对地下洞室产生的影响有差异；若有软弱夹层分布时，应采取措施控制软弱夹层引起的位移、拉应力区以及塑性区的增加。 |
| 关键词: 地下洞室 软弱夹层 分布位置 围岩级别 稳定性 安全性 |
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| 基金项目:国家自然科学基金项目(50708034，50879068);陕西省教育厅科研计划项目（11JK0730） |
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| Effect of weak interbed on tunnel stability in different graded surrounding rock mass |
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| Abstract: |
| 【Objective】The research was done to study the effect of the weak interbed distributed in rock mass with different grades on the stability of surrounding rock mass of tunnel and the safety of supporting system.【Method】Systematic numerical tests were carried out to study the displacement vector field,the stress vector field,the plastic region of surrounding rock mass and the stress in shot-crete with a weak interbed distributed in crown,shoulder and side wall respectively by mains of the FEM code FINAL introduced from Austria.【Result】The displacement in tunnel crown was increased by about 85%,the displacement at walls of both side decreased by 30%-35% and tensile zone in surrounding rock mass increased by 4.0-5.0 times,under the condition that tunnel with crown weak interbed was located in surrounding rock mass graded Ⅱ,Ⅲ.In surrounding rock mass graded Ⅳ,the displacement in crown of tunnel was increased by 120%,the displacement at walls of both side increased by 10% and tensile zone in surrounding rock mass increased inconspicuously.When the tunnel was surrounded by rock mass graded Ⅱ and Ⅳ,the depth of plastic zone changed little,but in graded Ⅲ,the depth of plastic zone doubled.【Conclusion】The same weak interbed distributed around tunnel,showing different effect characteristics in surrounding rock mass with different grades,and some measurements should be carried out to deal with the increase of displacement,tensile zone and plastic zone in surrounding rock mass with weak interbed. |
| Key words: underground opening weak interbed distribution location grade of surrounding rock mass stability safety |
