In this paper, a three-dimensional finite difference analysis is presented to investigate the interactive effects of sequential tunneling and the superstructure on the settlement profile of the ground. To simulate the practical sequential tunneling procedure, tunnel excavation is conducted in a step-by-step framework; tunnel excavation starts from the beginning of the model and is updated in a continuous manner, and the installation of the tunnel support system is done with a delay step compared to tunnel excavation. The numerical modeling accuracy is validated using the available analytical and numerical solutions for both two-dimensional and three-dimensional simplified cases. The well-validated modeling procedure is adopted to investigate effects of tunnel diameter, depth of tunneling, and number of superstructure stories on the profile of occurring settlements. Two cases of free-field and three-dimensional superstructural modeling are compared with regard to the effect of tunneling. In addition, the effect of tunneling advancement on the generation of excess structural forces and moments are studied as another important factor in the soil-tunneling-superstructure interaction problem. It is observed that, in the free-field case, with advancing the tunnel face, the longitudinal settlement profiles approach the steady-state condition and the maximum ground settlement tends to converge to a specific value, whereas as the tunnel passes under a structure, the settlement increases steadily as the tunnel progresses. There is a direct relationship between the depth and diameter of the tunnel and the settlement. In addition, the effect of the number of superstructure stories on the maximum settlement is more considerable compared to the free-field condition. According to the results, when the tunnel passes under 8-story and 12-story structures, the maximum settlement increases by 40% and 70%, respectively, compared to the free-field condition. It is also shown that tunneling-induced settlements result in the regeneration of structural forces.

中文翻译：

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地序隧道-上部结构相互作用的三维有限差分分析

在本文中，提出了三维有限差分分析来研究连续隧道和上部结构对地面沉降剖面的交互影响。为了模拟实际的顺序隧道开挖过程，隧道开挖是在一个循序渐进的框架中进行的；隧道开挖从模型的开始开始并以连续方式更新，与隧道开挖相比，隧道支护系统的安装延迟了一步。使用二维和三维简化情况的可用解析和数值解来验证数值建模精度。采用经过充分验证的建模程序来研究隧道直径、隧道开挖深度、以及发生定居点概况的上层建筑层数。就隧道效应的影响，比较了自由场和三维上层结构建模的两种情况。此外，隧道推进对超结构力和力矩产生的影响作为土-隧道-上部结构相互作用问题中的另一个重要因素进行了研究。观察到，在自由场情况下，随着隧道掌子面的推进，纵向沉降剖面接近稳态条件，最大地面沉降趋于收敛到一个特定值，而当隧道穿过结构下方时，随着隧道的推进，沉降稳定增加。隧道的深度和直径与沉降有直接关系。此外，与自由场条件相比，上层建筑层数对最大沉降的影响更为显着。结果表明，隧道通过8层和12层结构下时，与自由场条件相比，最大沉降分别增加了40%和7​​0%。还表明隧道引起的沉降会导致结构力的再生。