常规的弹性解无法对具有强蠕变特性的软岩隧道变形规律提出合理解释。因此,针对软岩隧道施工的时间-空间效应,引入Burgers模型揭示其时空演化规律,并通过数值计算探究不同因素对粘弹性围岩纵向变形规律的影响。同时基于响应面法得到位移释放系数的经验公式,与现场监测和其他理论比较验证了本文方法的可行性。研究结果表明地应力对位移释放系数影响可忽略,Kelvin剪切模量、Kelvin粘滞系数、Maxwell剪切模量和开挖速度显著影响位移释放系数,而根据粘滞时间的不同可分为低延滞系数、中延滞系数和高延滞系数三类;针对时间效应影响型、空间效应影响型和时空效应影响型三种粘弹性围岩纵向变形曲线类型拟合得到相应的经验公式。本研究结论可为软岩隧道变形预测提供更简便的方法。
Conventional elastic solutions cannot explain the deformation characteristic of soft rock tunnels with creep characteristics. Therefore, a Buegers model is introduced to demonstrate the space time effects in the soft rock tunnel construction period. The influence of different factors on the longitudinal deformation rule of viscoelastic rock and the spatiotemporal evolution rule have been revealed through numerical simulations. At the same time, an empirical formula for the displacement release coefficient was obtained based on the response surface method. The feasibility of the proposed method was verified by comparing it with on-site monitoring and other theoretical results. The research results indicate that the influence of geostress on the displacement release coefficient can be ignored. The Kelvin shear modulus, viscosity coefficient, Maxwell shear modulus, and excavation speed significantly affect the displacement release coefficient. According to the difference in viscosity time, it can be divided into three categories: low, medium, and high hysteresis coefficient. Empirical formulas were fitted for the longitudinal deformation curve, including time, spatial, and spatiotemporal. The research conclusion can provide a more convenient method for predicting the deformation of soft rock tunnels.