The mechanized tunnelling process is mainly coupled with precast concrete segments, which include segmental rings that they are placed in their place simultaneously with the boring operation. Segments are mainly loaded by thrust jacks during the installation stage. It is essential to limit the cracks and damages of the segments during this stage to be sure of their structural integrity and sustainability. Stepping on the circumferential joint is a problem that can occur during the ring assembly. The main purpose of this study is to investigate the effect of the stepping under the load caused by thrust jacks. For this aim, the occurred stepping has been analyzed in the Tabriz metro line 2 project. In this research, the stepping has been investigated in four states, including non-stepping state, 1-cm stepping state, 2-cm stepping state, and 3-cm stepping state. Each state also has four positions, which include stepping on the right side of the ring, on the left side, on the floor, and on the roof. According to the results of the numerical modeling, increasing the amount of the stepping increases the damages. These damages have reached their highest level when the segment has stepping at the roof position.

中文翻译：

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TBM推力千斤顶下台阶对预制隧道段周向缝影响的数值研究

机械化的掘进过程主要与预制混凝土节段结合，这些混凝土节段包括分段环，它们在钻孔操作的同时放置在适当的位置。在安装阶段，节段主要由推力千斤顶加载。必须在此阶段限制分段的裂缝和损坏，以确保其结构完整性和可持续性。在环组件上可能会出现踩踏圆周接头的问题。这项研究的主要目的是研究在推力千斤顶引起的负载下的踩踏效果。为此，已经在大不里士地铁2号线项目中分析了发生的踩踏现象。在本研究中，已对踩踏分为四种状态进行了研究，包括非踩踏状态，1-cm踩踏状态，2-cm踩踏状态，和3厘米的踩踏状态。每个状态还具有四个位置，包括在环的右侧，左侧，地板和屋顶上踩踏。根据数值模拟的结果，增加步进量会增加损坏。当路段踩到车顶位置时，这些损坏已达到最高水平。