膨胀岩隧洞时效变形预测模型及应用

Time-Dependent Deformation Prediction Model and Its Application for Tunnelling in Swelling Rock Mass

膨胀性软岩隧洞变形是一个以吸水膨胀性变形为主,蠕变、扩容等多因素影响的复杂时变问题。为了预测隧洞开挖后围岩的变形,假设隧道围岩遵循Burgers体与Hoek-Brown准则组合的黏弹塑性模型,并结合湿度场理论和非关联的流动法则,推导了膨胀性软岩遇水工况下的黏弹-塑性时效变形方程,最后根据所得的位移解析式,结合理想案例和Nabetachiyama隧道实例分析了不同参数对深埋圆形隧洞围岩位移随时间变化的影响规律。结果表明:采用的预测模型可以较好地预测膨胀性软岩在遇水工况下的时效变形,且参数相对较少,物理意义明确,识别简单,本文方法可以很好地应用于地下工程实践。

Tunnel deformation in swelling soft rock is a complex time-dependent problem,which is mainly affected by swelling incurred by water absorption,creep and dilatancy.To describe this process,the surrounding rock of the tunnel is supposed to a viscoelastic-plastic combination model of a Burgers body and Hoek-Brown criterion.The viscoelastic-plastic deformation expression is derived based on the humidity field theory and the non-associated flow rule.And then,the effect of different parameters on the displacement of surrounding rock of deep-buried circular tunnel versus time is analyzed according to the obtained displacement analytical solution in combination with ideal examples and Nabetachiyama Tunnel.Results show that the prediction model can better predict the time-dependent deformation in swelling soft rock under water condition with relatively few parameters,clear physical meaning,and simple identification,and it can be well applied to engineering.