【摘要】 对在建的穿越5·12强震区发震断裂带上广甘高速公路杜家山软岩隧道中多次出现的大变形及塌方等地质灾害特征、影响因素及其成因机制的分析表明:强震区软岩隧道变形破坏多以坍塌为主,且多数发生于掌子面附近;围岩自稳能力差及地下水对岩体的软化作用是隧道发生变形破坏的主要诱因,但5·12强震及后期余震作用形成的大量深部震裂损伤岩体也是产生上述现象的重要因素之一,复杂的区域环境造成设计、施工中类似经验不足也是引发上述现象不可忽视的重要环节。研究表明,对于强震区软岩隧道应结合现场实际情况适当调整围岩的预留变形量及安全控制基准,加强原有的支护参数,施工中重视各环节的工艺衔接,采用以三台阶+预留核心土的微台阶法可有效控制上述灾害的产生。更多还原

【Abstract】 Based on the study of repeatedly appearing geological hazards such as large deformation and collapse,and the formation mechanism and influencing factors of Dujiashan tunnel through soft rock which is under construction for Guangyuan—Gansu expressway,traversing the 5.12 fault zone in meizoseismal areas,it was shown that collapses were the main deformation failure of soft rock tunnels in meizoseismal areas;and most of them happened near the tunnel faces.The low strength of surrounding rock and softening effect from groundwater on rock mass are inducements of tunnel s deformation,and there is also a vital factor that causes the phenomena above,i.e.the effect of the massive deep shattering damaged rock mass caused by 5.12 Wenchuan earthquake and the aftershocks.At the same time,the complicated regional environment caused by insufficient similar experience in design and construction is another key factor that cannot be ignored.The research indicates that,during the construction of soft rock tunnels in meizoseismal areas,proper adjustments of reserved deformation and safety control criterion should be taken based on practical engineering site,strong supporting parameters should be adopted,the techniques connecting each link during construction should be paid attentions to,and the disasters can be effectively controlled with the adoption of micro-bench method using three steps and reserved core soil excavation.更多还原