The mechanism of the soil arching effect determines the overburden pressure of deep-buried shield tunnel, which has not been fully studied. 3 model tests for deep-buried shield tunneling with different vertical pressures acting on the top of the ground were carried out. The changes in the ground stress, displacement, and shear strain during the model tunnel contraction were measured. The experimental results indicated that the two-stage development characteristic of the initially linear rapid decrease followed by the slow reduction was found in the ground reaction curve. Furthermore, the higher the stress level, the slower the development speed of the soil arching, the more pronounced the lag of the soil arching, and the smaller the range of the soil arching. The development of the shear band was controlled by the stress-dependent soil dilatancy. Under the low-stress level, the shear band above the tunnel develops vertically upwards. While under high-stress levels, the shear bands tilt towards both sides. The relevant research results will lay a solid foundation for accurately determining the load of the deep-buried tunnel.

中文翻译：

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深埋盾构掘进诱导土体拱起效应的试验研究


土体拱起效应的机理决定了深埋盾构隧道的覆盖层压力，目前尚未得到充分研究。开展了 3 次不同竖向压力作用在地表顶部的深埋盾构隧道模型试验。测量了模型隧道收缩过程中地应力、位移和剪切应变的变化。实验结果表明，在地面反应曲线中发现了最初线性快速下降后缓慢减少的两阶段发展特征。此外，应力水平越高，土体拱起的发展速度越慢，土体拱起的滞后越明显，土体起拱的范围越小。剪切带的发展受应力依赖性土壤膨胀的控制。在低应力水平下，隧道上方的剪切带垂直向上发展。在高应力水平下，剪切带向两侧倾斜。相关研究成果将为准确确定深埋隧道荷载奠定坚实的基础。