高地应力炭质板岩隧道大变形灾变力学行为演化及预测方法

High geostress soft rock tunnel is prone to large deformation disasters, such as invasion, support structure damage and so on. Reasonable prediction of large deformation catastrophic behavior is very important for tunnel design and construction. Taking the high geostress carbonaceous slate tunnel as the research object, this project intends to study the basic mechanical parameters, deformation characteristics and rheological characteristics of surrounding rock samples with structural plane inclinations by means of experimental testing, theoretical analysis and numerical simulation, analyze the mineral composition and micro-structure of complete rock samples and fracture surfaces, and reveal the evolution mechanism of instantaneous and long-term mechanical behavior of high geostress carbonaceous slate; Based on the fractional calculus theory, a three-dimensional large deformation nonlinear viscoelastic-plastic rheological constitutive model considering different structural plane inclination is established. The long-term mechanical behavior of the carbonaceous slate is numerically simulated. The relationship among structural plane inclinations, mineral composition, micro-structure and constitutive model is discussed; Based on the established constitutive model, a catastrophic mechanical behavior evolution model of carbonaceous slate tunnel with large deformation is established, and the characteristic parameters in the catastrophic process are determined. The dynamic prediction method of the whole process of large deformation catastrophe is proposed. The research results can provide a scientific basis for the prevention and control of large deformation disasters in high geostress carbonaceous slate tunnels.

高地应力软岩隧道易发生变形侵限、支护结构破坏等大变形灾害，合理预测大变形灾变行为对隧道设计和施工至关重要。本项目以高地应力炭质板岩隧道为研究对象，拟采用试验测试、理论分析和数值模拟相结合的方法，研究不同结构面倾角炭质板岩岩样的基本力学参数、变形特征和流变特性，分析完整岩样及破坏断口的矿物成分和微细观结构，揭示高地应力炭质板岩瞬时和长期力学行为演化机理；基于分数阶微积分理论，建立考虑不同结构面倾角的大变形非线性粘弹塑性流变本构模型，进而模拟炭质板岩长期力学行为，并探讨结构面倾角、矿物成分和微细观结构与本构模型的关联关系；依据所建本构模型，建立炭质板岩隧道大变形灾变力学行为演化模型，确定灾变过程中的特征参数，提出大变形灾变全过程动态预测方法。研究成果可为高地应力炭质板岩隧道大变形灾害防控提供科学依据。

高地应力软岩隧道易发生变形侵限、支护结构破坏等大变形灾害，合理预测大变形灾变行为对隧道设计和施工至关重要。本项目采用试验测试、理论分析和数值模拟相结合的方法，开展了炭质板岩隧道围岩瞬时和长期力学行为、大变形粘弹塑性本构模型和灾变预测方法研究。经过三年研究取得以下成果：研究了高地应力炭质板岩隧道围岩的瞬时和长期力学特性，归纳其力学特性随结构面倾角的变化规律，揭示了高地应力状态下炭质板岩隧道围岩瞬时和长期力学行为的演化机理；借鉴元件组合模型的建模思路，构建考虑不同结构面倾角的三维非线性粘弹塑性流变模型，推导得出了该模型的本构方程，对模型进行参数辨识，并结合试验结果对比验证了所建本构模型的合理性；基于炭质板岩隧道围岩变形数值模拟分析结果，建立了基于遗传算法优化的支持向量机参数寻优的隧道围岩时间序列预测模型，预测了木寨岭隧道围岩的变形演化规律，确定大变形灾变过程中的特征参数，提出高地应力炭质板岩隧道大变形灾变预测方法。研究成果可为高地应力炭质板岩隧道大变形灾害防控提供理论支撑和技术支持。