城市隧道施工诱发的地面塌陷灾变机制及其控制

基于国内城市隧道施工过程中地面塌陷事故频发的现状,结合地面塌陷事故案例,对城市隧道施工诱发的地面塌陷灾变机制及其控制技术进行了研究。通过对北京地铁隧道施工诱发的44起安全事故统计发现:地面塌陷事故共16起,占全部事故的36%,所占比例较高;通过对国内城市隧道施工引起的29起地面塌陷事故统计发现:管线渗漏和不良地质体是诱发地面塌陷的主要因素,两者诱发的事故合计比例高达69%,因此也是地面塌陷防控的关键性因素。根据案例统计分析结果,将地面塌陷的形成方式划分为3种类型,分别为:隧道施工直接导致上覆地层失稳破坏形成的地面塌陷,隧道施工导致地层中不良地质体破坏而形成的地面塌陷,以及隧道施工导致管线渗漏水恶化而引发的地面塌陷。采用理论分析和数值模拟揭示了城市隧道施工诱发地面塌陷的灾变机制及其演化规律,在此基础上提出了城市隧道施工过程中地面塌陷的控制技术。

Catastrophe mechanism and control technology of ground collapse induced by urban tunneling

Based on the current status of frequent ground collapse during the urban tunneling, the catastrophe mechanism and control technology of ground collapse induced by urban tunneling are studied combined with ground collapse accident cases. The statistics of 44 safety accidents induced by Beijing Metro tunneling show that there are 16 ground collapse accidents out of the 44 cases, accounting for high percentage (36%). The statistics of 29 ground collapse accidents induced by urban tunneling show that pipeline leakage and unfavorable geologic bodies are the main inducing factors to cause ground collapse, accounting for 69% of all the inducing factors. So the pipeline leakage and unfavorable geologic bodies are the key factors to prevent and control ground collapse accidents. According to the statistical analysis results, the ground collapse forms are divided into three categories as follows: ground collapse directly induced by instability of overlying strata in tunneling, ground collapse indirectly induced by failure of unfavorable geologic bodies in strata in tunneling, and ground collapse indirectly induced by pipeline leakage or damage in tunneling.The catastrophe mechanism and evolution law of ground collapse induced by urban tunneling are introduced by using theoretical analysis and numerical simulation, and then the corresponding measures are put forward to control ground collapse in urban tunneling.