盾构隧道接缝渗漏水诱发既有管线变形模型试验

Model test on deformation of existing pipeline induced by joint leakage of shield tunnels

基于临界漏缝宽度,建立盾构隧道接缝渗漏水诱发邻近地下管线变形的模型试验系统,包括盾构隧道与管线模型、盾构隧道接缝渗漏模拟装置、水位控制系统、数据采集系统等,研究漏缝位置、漏缝分布形式、覆土深度对管线变形沉降、管线内力和漏缝周围土体孔隙水压力的影响规律。试验结果表明:随着覆土深度不断增加,漏缝距离管线的垂直距离增加,且富水砂层将产生更大的应力支撑上部水土压力,管线沉降变形及内力不断减小;相同覆土深度条件下,随着漏缝位置向拱底发生偏移,管线沉降变形峰值及内力峰值逐渐减小,所对应位置逐渐远离隧道中心轴线,漏缝一侧上方管线沉降变形明显,影响范围扩大;单侧漏缝数量增多,新增漏缝位置越靠近拱顶,管线沉降变形及内力增幅越大;双侧对称漏缝工况下,管线沉降变形及内力关于隧道中心轴线对称;双侧非对称漏缝工况下,管线沉降变形及内力关于隧道中心轴线呈明显的非对称性。监测孔隙水压力可以合理地解释盾构隧道漏缝周围土体渗流场的分布情况,越靠近漏缝位置,监测孔隙水压力越小,消散孔隙水压力越大,水总是从孔压高的位置流向孔压低的位置。

Based on the critical leakage width,a model test system of adjacent pipelines deformation induced by the joint leakage of shield tunnel was established,including the shield tunnel and pipeline model,simulation device of shield tunnel joint leakage,water level control system,and data acquisition system,the influences of the position,distribution and depth of the leakage on the deformation and settlement of the pipeline,the internal force of the pipeline and the pore water pressure of the soil around the leakage were studied.The results showed that with the increasing of the depth of the overburden soil,the vertical distance between the leak and the pipeline increased,and the water-rich sand layer would produce more soil and water pressure on the upper part of the support,and the settlement deformation and internal force of the pipeline would decrease under the condition of the same depth of overburden soil,the peak value of settlement and internal force of the pipeline decreased gradually as the position of the leakage seam deviated to the bottom of the arch,the corresponding position gradually moved away from the central axis of the tunnel,and the settlement deformation of the pipeline above the leakage seam side was obvious,the settlement deformation and internal force increase with the increased of the number of the single side leakage,the location of the new leakage was close to the arch crown under the condition of bilateral asymmetric leakage,the settlement deformation and internal force of the pipeline were obviously asymmetric with respect to the central axis of the tunnel.The monitoring value of pore water pressure could reasonably explain the distribution of seepage field around the leakage of shield tunnel.The closer to the leakage location was,the smaller the monitoring value of pore water pressure and the larger the dissipation value of pore water pressure was,water always flowed from a high to a low pore pressure position.