软土地层隧道盾构施工扰动固结机理初探

软土地层盾构施工与坚硬岩体中的新奥法施工对围岩应力的影响机理在本质上是不同的。在软土中盾构施工对周围土体的影响机理对城市地铁建设有重要意义。盾构施工对周围土体产生的挤压、剪切、拉伸作用,通过室内力学试验与数值模拟盾构施工对周围土体的力学作用,初步分析土体的力学变化;然后根据室内微观试验(电镜扫描)对已做力学实验的样本进行微观扫描分析,发现土体在受到挤压、剪切、拉伸的过程后土体发生了固结(土体颗粒变均匀与致密),即认为扰动固结圈的存在。为了进一步研究扰动固结圈的范围,通过建立不同净距的数值模拟模型,计算它们之间的相互影响关系,从而确定其固结圈的大小(划分为强扰动固结、弱扰动固结、无扰动固结)。在此基础上,进一步给出了扰动固结圈的定义、形成条件,为类似工程的研究提供参考依据。

Preliminary study on the disturbed consolidation mechanism of tunnel shield construction in soft stratum

The influence of the new Austrian Tunneling Method on the construction of soft soil shield tunnel and hard rock mass is different in nature. In soft soil, the influence mechanism of shield construction on surrounding soil is important for urban subway construction. The mechanical analysis of the soil around the soil was made by the mechanical test and numerical simulation of the surrounding soil, and the soil was considered to be the consolidation of the soil in the process of extrusion, shear and tension, which was considered to be a disturbance. In order to further study the range of the disturbance consolidation circle, a numerical simulation model was established to calculate the mutual influence between them. On this basis, the definition and the forming conditions of the disturbance consolidation circle were given, which provide reference for the similar engineering.