隧道软弱卧层的危害、防治及现场判识之探讨

隧道软弱卧层的存在,对施工和运营安全危害极大,当其位于围岩应力场范围,会引起隧道瞬间发生异常沉降,引发地质灾害。结合工程实例,对隧道软弱卧层的危害提出了相应的处理和防治措施,在施工中取得了预期的效果。同时通过现场调查及对软弱卧层作用机理的研究,指出不能通过变形量测或解析方法预测软弱卧层的存在,在变形量测结果正常、基底承载力符合设计要求的情况下,如果伴随洞内地表异常隆起,可作为软弱卧层存在的基本判据;地质超前预报是发现和预防软弱卧层危害的最主动、最有效的手段;对围岩和软弱卧层进行注浆加固,是防治其危害最直接、最有效的手段。研究结果对同类隧道工程问题具有借鉴和参考价值。

On Hazard,Prevention and Identification of Soft Sublayer in Tunnel Construction

Soft sublayer is greatly harmful to the safety construction and operation.If it is located in the stress field of wall rock,it will induce the tunnel to an abnormal setdement instantly and then the geological hazard will be followed.In this paper,the corresponding disposable and preventive measures to the hazard of soft sublayer are put forward and the expected effect has already been got.The research indicates that the existing of soft sublayer can not been forecasted by the deformation measurements or analytical methods.It is pointed out that the abnormal swelling on the ground of cave with the normal deformation measurement results and bearing capacity meeting the design requirements can be considered as the basis judgement of the existing of soft sublayer.Geological prediction is the most active and effective means to discover and prevent the hazard of soft sublayer.Grouting reinforcement in the wall rock and soft sublayer is the most direct and effective means to prevent the hazard.The research results can provide reference to the similar tunnel engineering problems.