Abstract

Due to long-term coupling of ground stress and water pressure during operation processes, lining concrete will experience different degrees of cracking and spalling, which seriously affect the safety of tunnels during service. In this paper, lining concrete seepage tests under different confining pressures are performed; the mechanical properties and acoustic emission (AE) responses during the loading process and the relationship between load-induced plastic deformation and lining concrete specimen permeability are studied. The plastic internal variable definition is introduced to characterize concrete specimen plastic deformation and is calculated after unloading. Different initial stress states and stress levels during loading and unloading processes affect pore and fissure development in lining concrete. The peak intensity increases with increasing confining pressures, and deformation parameter variation has elastoplastic coupling characteristics. AE parameters and axial stress show good agreement. The AE signal of the samples shows a transition from the Kaiser effect to the Felicity effect before the peak, indicating that AE can be an effective means of monitoring internal sample damage. A power function relationship can represent the relationship between the initial permeability and confining pressure, and the permeability evolution model of concrete samples in the plastic phase is established after the initial yielding.

摘要

由于在运营过程中地应力与水压长期耦合，衬砌混凝土会出现不同程度的开裂剥落，严重影响隧道运营期间的安全。本文进行了不同围压下的衬砌混凝土渗流试验；研究了加载过程中的力学性能和声发射（AE）响应，以及加载引起的塑性变形与衬砌混凝土试件渗透率之间的关系。引入塑性内变量定义来表征混凝土试件的塑性变形，并在卸载后进行计算。加载和卸载过程中不同的初始应力状态和应力水平会影响衬砌混凝土的孔隙和裂缝发展。峰值强度随着围压的增加而增加，变形参数变化具有弹塑性耦合特性。声发射参数和轴向应力表现出良好的一致性。样品的AE信号在峰值前呈现出从Kaiser效应到Felicity效应的过渡，表明AE可以成为监测样品内部损伤的有效手段。幂函数关系可以表示初始渗透率与围压之间的关系，在初始屈服后建立塑性阶段混凝土样品的渗透率演化模型。样品的AE信号在峰值前呈现出从Kaiser效应到Felicity效应的过渡，表明AE可以成为监测样品内部损伤的有效手段。幂函数关系可以表示初始渗透率与围压之间的关系，在初始屈服后建立塑性阶段混凝土样品的渗透率演化模型。样品的AE信号在峰值前出现了从Kaiser效应到Felicity效应的过渡，表明AE可以成为监测样品内部损伤的有效手段。幂函数关系可以表示初始渗透率与围压之间的关系，在初始屈服后建立塑性阶段混凝土样品的渗透率演化模型。