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厦门海底隧道工程穿越四条断层破碎带,破碎带处洞体围岩软弱、破碎,岩石主要为风化破碎类花岗岩,其流变时效属性非常显著。通过对风化破碎类花岗岩试样进行流变试验研究,建立适合风化囊围岩特点的流变力学模型;再在考虑围岩流变时效的基础上,采用有限元数值模拟方法,开展风化囊围岩-支护系统的相互作用研究。研究表明:松散破碎岩体的流变时效作用明显,在隧道的设计施工中必须计入粘性蠕变的影响;风化囊区段的隧道二衬厚度采用60cm是合适的,不宜再过分增厚;为确保工程安全,开挖后立即施作初期支护,紧跟施作二衬支护。最后,阐述了围岩变形速率比值判别的施工变形控制方法,在判据认定的险情区段,必须实时加固,避免塌方。
The Xiamen Cross-Harbor Tunnel project passes through four fault-broken zones. The surrounding rock of the cave body at the fractured zone is weak and broken. The rock is mainly weathered and crushed granite, and its rheological aging property is very significant. Through the rheological experiments on the weathered and crushed granite samples, the rheological mechanical model is established to suit the characteristics of the surrounding rock of the weathering sac. Based on the rheological aging of the surrounding rock, the finite element method Study on Interaction of Rock and Shoring Systems. The results show that the rheological aging effect of loose crushed rock mass is obvious, and the influence of viscous creep must be taken into account in the design and construction of the tunnel. The thickness of tunnel lining of weathering sac section is suitable for 60cm and should not be excessively thickened. In order to ensure the safety of the project, the initial support is applied immediately after excavation, followed by the second lining support. Finally, the method of construction deformation control for judging the ratio of surrounding rock deformation rate is expounded. In the danger zone determined by the criterion, it is necessary to reinforce it in real time to avoid landslide.