Finite Element Analysis of Expansive Bedrock Considering Electro-chemo-mechanical Coupling Phenomena in Crystal Layers of Clay Minerals and Internal Structural Degradation
Finite Element Analysis of Expansive Bedrock Considering Electro-chemo-mechanical Coupling Phenomena in Crystal Layers of Clay Minerals and Internal Structural Degradation
复制标题
考虑粘土矿物晶层电化学-机械耦合现象和内部结构退化的膨胀基岩有限元分析
DOI：
10.1007/s00603-022-02997-3
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发表时间：
2022
影响因子：
6.2
通讯作者：
Kyoya Takashi
中科院分区：
文献类型：
--
作者：
Hoshi Keitaro;Yamada Shotaro;Kyoya Takashi
本研究提出了一种新的模型，针对膨胀性基岩相结合的弹塑性模型，考虑电化学力学现象与凸轮粘土模型，考虑胶结和降解，由于塑性变形。此外，隧道开挖和膨胀分析表明，将所提出的模型纳入有限元分析代码。具体而言，通过降低基岩离子浓度并考虑地下水对隧道的供应来进行膨胀分析。模拟结果表明，相当大的膨胀发生在一个有限的区域，如隧道的底部，即使在离子浓度的变化是均匀地设置在整个分析区域;此外，膨胀现象发展瞬间类似于观测记录。模拟结果表明，随着开挖面积的增加，基岩骨架中的剪应力逐渐增大，随着离子浓度的降低，基岩骨架发生了塑性膨胀软化。此外，根据模拟，基岩骨架的屈服引发了内部结构的快速退化和粘土矿物层间层的膨胀。因此，本研究阐明了隧道膨胀变形机制之间的相互作用问题耦合的电化学机械现象发生在晶体层和塑性现象，涉及内部结构退化的基岩骨架。
This research proposes a novel model targeting expansive bedrock by combining an elastoplastic model considering electro-chemo-mechanical phenomena with the Cam-clay model, based on considerations of cementation and its degradation owing to plastic deformation. Additionally, tunnel excavation and swelling analyses are demonstrated by incorporating the proposed model into a finite element analysis code. Specifically, swelling analysis is conducted by decreasing the bedrock ion concentration and by considering the groundwater supply to the tunnel. The simulation results indicate that considerable swelling occurs in a limited area, such as the bottom part of the tunnel, even though changes in ion concentration are uniformly set in the entire analysis area; moreover, swelling phenomena develop instantaneously analogous to the observational records. The simulation reveals that shear stress increases while excavating an area and that softening with plastic expansion occurs in bedrock skeleton owing to decreasing ion concentration. In addition, the yielding of the bedrock skeleton triggers a rapid internal structural degradation and swelling of the clay mineral interlaminar layers based on simulations. Thus, this study clarifies the tunnel swelling deformation mechanism as an interaction problem between coupled electro-chemo-mechanical phenomena occurring in crystal layers and a plastic phenomenon involving the internal structural degradation of the bedrock skeleton.