盾构法隧道的位移反分析及其工程应用

在盾构法隧道中将衬砌周围由于盾尾空隙的闭合、注心充填作用和盾构推进对周围地层的扰动等形成的特殊圈层概化为具有平均意义的等代层，其参数一般可根据土质条件选取，但不易准确，在有实测地层位移资料时，用位移反分析法可较准确地获取等代层的参数，根据循构法隧道的施工特点，选择等代层的厚度和弹性模量作为反分析参数，这样既简化了反分析的过程，又使反分析结果的意义更为明确，实例分析表明，本文所采用的直接反分析方法是有效的、可靠的，反分析所获得的等代层参可较好地用于模拟盾构法隧道施工时地层位移随开挖面推进的动态变化。

Inverse Analysis on Displacements of the Shield Tunnel and Its Application to Engineering

With respect to the forming mechanism of soil displacement and constructing characteristics of the shield tunnel, the concept of equivalent circle zone is supposed. The soil around the lining is generalized to the equivalent circle zone in order to consider the size of void at the shield tail, the degree of filling grout and the disturbance of soil around the shield due to its advancing. The parameters of the equivalent circle zone may be obtained from the soil condition, but they are difficult to be directly measured from the in?situ or indoor tests and are usually inaccurate. When the measured displacements are obtainable, the inverse analysis on displacements is employed to gain the thickness and elastic modulus exactly. The optimal complex method is used in the back analysis. A pedestrian tunnel is analyzed in the paper, in which the subsidence at 150?m cross?section is estimated with the parameters that are obtained by back analyzing according to the measured layer?wise subsidence at 50 m cross?section. The calculated result is close to the measured result very well. The example shows that the direct inverse analysis method is effective and reliable for the shield tunnel, and the supplied parameters can be used to simulate the process of soil displacements well which will change with the advancing of the excavated face.