箱涵顶进对下方管幕的力学作用分析

采用管幕-箱涵法施工的超浅埋连接通道跨越运营地铁时，施工前对场地的土堆清理及基坑开挖工作已使地铁隧道产生较大变形，为确保地铁的安全运营，对后续管幕、箱涵的施工进行严格控制。利用解析计算的方法，根据箱涵相对原状土等效重力大小的不同，建立2种力学模型，分别按照弹性地基梁和普通梁2种模型对管幕的受力进行研究； 推导出2种计算模型下的力学公式，分析在箱涵顶进的过程中，箱涵下方管幕受力和变形的变化规律，为进一步研究管幕下方地铁隧道的受力情况提供参考。

Analysis of Mechanical Effect of Box Culvert Jacking on Bottom Pipe Curtain

When the ultra shallow buried underpass constructed with the method of pipe curtain box culvert strides over the operation subway, the mound cleaning and excavation of foundation pit before construction often cause subway tunnel deformation. In order to ensure the safe operation of subway, the subsequent construction of pipe curtain and box culverts must be strictly controlled. In this paper, based on analytical calculation method, two mechanical models are established according to the difference between the equivalent gravity of box culvert and undisturbed soil. The force of pipe curtain is studied with elastic foundation beam model and ordinary beam model, and the two kinds of forces are derived respectively. The mechanical formula under the two calculation models is used to analyze the variation law of the force and deformation of the pipe curtain during jacking process of box culvert, which provides a basis for further study of the force of subway tunnel under pipe curtain.