The combined supporting system of rockbolts and linings is one of the most common methods for controlling the deformation of surrounding rock in tunnels. However, current theoretical analyses typically consider the deformation control effect of only one support type. Consequently, the bearing capacity of rockbolts or linings is not fully utilized as their combined effect is not considered. Thus, this study analyzes the mechanical responses of a “rockbolts + lining” combined supporting system for large deformation tunnels. For theoretical derivation, a viscoelastic–viscoplastic constitutive model is employed to describe the time-dependent behavior of surrounding rock. To satisfy the actual deformation development law, the effect of the stress path in the plastic zone of the surrounding rock is considered. An analytical solution is provided for predicting the tunnel behavior, where the installation time of the rockbolts and lining is considered sufficiently. Furthermore, the proposed analytical solution can be reduced to a viscoelastic solution and is well applied in a tunnel project. The superiority of the proposed solution is demonstrated by comparing it with previous solutions. Finally, a comprehensive parametric investigation is conducted, which considers the cohesion and internal friction angle of rock, the linear stiffness coefficient and installation time of rockbolts, and the stiffness and installation time of the lining. The results show that the cohesion and internal friction angle of the rock dominate the plastic deformation of the surrounding rock, thus further affecting tunnel deformation. The installation of rockbolts and lining can effectively restrict the deformation of the surrounding rock. Generally, better deformation control can be achieved by installing rockbolts (lining) earlier or by improving the stiffness of the rockbolts (lining). However, the stiffness of the rockbolts (lining) is limited to a certain range, in which significant deformation control can be achieved. After determining the installation time of the rockbolts and lining based on the actual construction level, the reasonable design parameters of the rockbolts and lining can be determined using the proposed solution such that their bearing capacities can be fully utilized in this combined supporting system.

中文翻译：

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使用组合支护系统对粘弹-粘塑性岩石隧道的力学行为进行更准确的理论预测


锚杆和衬砌的组合支护系统是控制隧道中围岩变形的最常用方法之一。然而，目前的理论分析通常只考虑一种支座类型的变形控制效应。因此，由于没有考虑锚杆或衬砌的综合效应，因此没有充分利用它们的承载力。因此，本文分析了“锚杆 + 衬砌”组合支护系统对大型变形隧道的力学响应。对于理论推导，采用粘弹性-粘塑性本构模型来描述围岩的时间依赖性行为。为了满足实际的变形发展规律，考虑了围岩塑性区应力路径的影响。提供了一种分析解决方案，用于预测隧道行为，其中充分考虑了锚杆和衬砌的安装时间。此外，所提出的解析解可以简化为粘弹性解，并很好地应用于隧道工程。通过与以前的解决方案进行比较，证明了所提出的解决方案的优越性。最后，进行全面的参数化研究，考虑岩石的内聚力和内摩擦角，锚杆的线性刚度系数和安装时间，衬砌的刚度和安装时间。结果表明：岩石的内聚力和内摩擦角在围岩塑性变形中占主导地位，从而进一步影响隧道变形;安装锚杆和衬砌可以有效限制围岩的变形。 通常，通过提前安装锚杆（衬砌）或提高锚杆（衬砌）的刚度，可以实现更好的变形控制。然而，锚杆（衬砌）的刚度被限制在一定范围内，在该范围内可以实现显著的变形控制。在根据实际施工水平确定锚杆和衬砌的安装时间后，可以使用所提出的解决方案确定锚杆和衬砌的合理设计参数，使其承载能力在这个组合支护系统中得到充分利用。