基于D-P准则三阶段蠕变模型的圆形隧洞黏弹塑性解

Viscoelastic-plastic Solution for Circular Tunnels Based on the Three-stage Creep Model with the D-P Criterion

  • 摘要: 围岩的流变特性对隧道结构的长期变形有重要的影响。为了较好地描述圆形隧道开挖后围岩的黏弹塑性力学行为,采用分数阶蠕变模型描述围岩的流变特征,采用Drucker-Prager准则表征围岩的塑性特征,推导圆形隧道开挖后考虑支护支撑效应的围岩应力-位移理论解。通过具体算例,分析围岩流变参数对黏弹性塑性变形的影响。结果表明:(1)解析得到的围岩蠕变位移曲线与现场实测结果平均值曲线吻合较好,证明理论推导具有正确性;(2)当考虑黏塑性区围岩的剪胀效应时,围岩的变形值增加。剪胀效应越明显,围岩变形值增加的量值越大;(3)当黏弹性体或黏塑性体的黏性增强时,围岩的蠕变位移量值和速率都会相应增加。

     

    Abstract: The rheological properties of surrounding rock significantly influence the long-term deformation of tunnel structures. To better describe the viscoelastic-plastic mechanical behaviors of the surrounding rock after circular tunnel excavation, a fractional-order creep model is used to characterize the rheological properties, and the DruckerPrager criterion is used to represent the plastic characteristics of the surrounding rock. The theoretical solution of the stress-displacement of the surrounding rock, considering the support effect after circular tunnel excavation, is derived. Through specific examples, the influence of rheological parameters on viscoelastic-plastic deformation of the surrounding rock is analyzed. The results show that: (1) The creep displacement curve of the surrounding rock obtained analytically matches well with the average curve of field measured results, proving the correctness of the theoretical derivation; (2) When the dilatancy effect of the surrounding rock in the viscoplastic zone is considered,the deformation value of the surrounding rock increases. The more pronounced the dilatancy effect, the greater the increase in the deformation value of the surrounding rock; (3) When the viscosity of the viscoelastic or viscoplastic body increases, the creep displacement value and rate of the surrounding rock also increase accordingly.

     

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