【作者】 曾杰；

【导师】 张永兴； 靳晓光；

【作者基本信息】 重庆大学 ， 桥梁与隧道工程， 2011， 博士

【摘要】 隧道埋深的增加,地应力逐渐增加,岩爆风险进一步加大,围岩变形的时间效应显著,而深埋环境下硬岩隧道开挖过程中围岩表现出特殊的非线性力学行为使得传统的岩石力学理论与分析方法面临着新的挑战。论文以国家杰出青年科学基金项目“岩土工程减灾（50625824）”为依托,开展深埋硬岩隧道围岩稳定性的研究:对围岩稳定的重要影响因素—二次应力场进行了研究,在此基础上针对深埋硬岩弹脆性破坏的主要形式-岩爆灾害进行了预测;分析了隧道围岩和支护结构的蠕变特性;借助耗散非线性科学理论,确定深埋隧道围岩的非线性动力学特征,即围岩稳定性与能量耗散之间的关系。论文的主要工作如下:①分析了测量隧道二次应力测试的改进的二次应力恢复法,即测定三个方向在应力解除前后应变的改变量,再进行二次应力恢复,根据应力恢复过程得到的压力,计算三个方向（ x、z和45°方向）的二次应力(σ_x、σ_z和σ₄₅)。进行室内试验和数值实验求解改进应力恢复法的应力等效系数,探讨应力等效系数与岩石力学参数、围岩压力大小之间的关系,修正了改进的二次应力恢复法,从而系统的研究了改进的二次应力恢复法测定隧道围岩二次应力的可行性和正确性。②采用改进的二次应力恢复法对隧道深埋硬岩段进行了二次应力的现场测定,比较改进的二次应力恢复法与弹性力学计算结果。进而探讨了在深埋硬岩开挖隧道,接近和通过某一段面时,围岩主应力的变化以及开挖对平面应力和剪应力主要影响范围以及地应力的变化对隧道断面不同部位的二次应力场的影响。③分析国内外岩爆预测的判据,选择岩爆发生所需的力学条件、完整性条件、储能条件和脆性条件作为岩爆预测指标。引入岩爆预测的相对隶属度概念,计算了岩爆的相对隶属度模糊矩阵和预测指标的权重,以信息熵来描述并比较岩爆评价中的不确定性,定义了加权广义权距离来表征岩爆的差异。根据最大熵原理建立了岩爆预测的模糊最优化模型,对国内外一些岩石地下工程实例进行了分析,预测结果与其他方法的分析结果以及实际情况基本一致。并将模型运用于葡萄山隧道岩爆预测,预测结果与实际岩爆情况符合较好。进一步应用蒙特卡罗法讨论了岩爆指标的随机误差权重对于预测结果的影响。④采用MTS-815液压伺服系统对隧道衬砌的混凝土和微晶白云岩试件进行了三轴压缩试验和蠕变试验,分析了隧道衬砌混凝土三轴压缩蠕变变形的特点,认为采用摩尔-库伦准则和Burgers模型串联组合而成的粘弹塑性模型可以合理的描述衬砌混凝土和微晶白云岩的蠕变特性。组合模型的粘弹性状态与Burgers模型一致,塑性状态与M-C模型一致,它不仅能够反映衬砌结构蠕变过程,且能模拟材料的粘弹塑性变形特性,解决了典型Burgers蠕变模型只能描述粘弹性蠕变的缺陷。同时也研究了三轴试验条件下组合蠕变模型参数的求解方法,得到隧道衬砌混凝土和围岩的蠕变参数,建立数值分析模型,研究深埋硬岩隧道围岩的蠕变特征。⑤选取隧道深埋硬岩段典型部位多个点的剪切应变时间序列,进行相空间重构。计算隧道不同部位的非线性动力学指标:Lyapunov指数和Kolmogorov熵,定量分析围岩系统演化过程中变形的非均匀性和非线性稳定性,发现深埋隧道围岩系统演化对初始条件的敏感性,处于混沌状态。⑥对深埋隧道硬岩围岩进行了长期的监控量测,分析围岩变形,发现不同与浅埋隧道的变形特征。利用DGM（2,1）、全域法、局域法和混沌重构相空间-灰色DGM（2,1）最优组合模型对深埋隧道的围岩变形进行了预测,结果表明组合模型（全域法+DGM）的综合预测误差比全域法和灰色DGM（2,1）模型都小,精度也很高,能很好地预测深埋硬岩隧道围岩的动态变形特征,得到了与实测位移一致的预测结果。更多还原

【Abstract】 The risk of rock burst will be higher and more nonlinear effect is manifested in the surrounding rock with the ground stress increased gradually because of the tunnel buried depth increasing. With special nonlinear mechanical behavior significant, the traditional theory for rock mechanics faces a new challenge.This research work is being supported by grants from National Science Fund for Distinguished Young Scholars of China （NO.50625824）. The secondary stress after excavated, a very important influencing factors for the stability of surrounding rock is studied. Rock burst, a familiar brittle fracture of hard rock in deep-buried tunnel, is forecasted using the method of optimal relative membership degree based on the maximum entropy principle. And meanwhile, the creep characters of surrounding rock and supporting structure are researched. The nonlinear characteristics in construction process of hard rock deep tunnel namely the relationship between energy dissipation and stability of surrounding rock are analyzed by means of nonlinear dissipative scientific theory.The main work and research conclusions are as follow:①An improved stress restoring method based on the historical stress restoring method is discussed. And the principle of improved stress restoring method is that: calculation the strain variation of the three directions; then restoration the secondary stress; calculation the secondary stress(σ_x、σ_zandσ₄₅) according to the pressure based on strain variation. The key coefficient of improved stress restoring method, equivalent coefficient, is obtained by laboratory test and numerical experiments. It is discussed the relationship between the rock mechanics parameters, cofining pressure and equivalent coefficient, and its feasibility and rightness are tested by field practice.②Secondary stress of hard rock tunnel sections is obtained by field test through improved stress restoring method. And the results are compared with that of elastic mechanics method. It is discussed that there is a relation between excavation distance and principal stress of surrounding rock, the influence scope of plane stress and shear stress to correct the improved stress restoring method. Furthermore, the principle how the ground stresses variation effect of stress field in some sections of tunnel has been studied.③The prediction standards of rock burst are selected including the conditions of mechanics、integrity、energy and brittle on the basis of the analysis rock burst criterion prediction at home and abroad. The concept of relative membership degree on the rock burst prediction was introduced. The weight of standards and fuzzy matrix of relative membership degree are calculated. Uncertainty in rock burst prediction is described and compared according to the information entropy. Generalized to weighted distance is also defined to characterize the differences in rock burst Based on the maximum entropy principle, the establishment of a rock burst prediction fuzzy optimization model. The results from the application to practical example and comparisons with other methods are fairly good. And the prediction model is applied in putaoshan tunnel and the predictions are consistent with the actual rock burst. Furthermore, it is discussed the ralationship between the random error-weight and predict results.④The triaxial compression creep test on supporting structure and micritic dolomite of the deep tunnel concrete specimens is performed by using the MTS-815 hydraulic servo system. A combined viscoelastic plasticity model is developed after the characteristics of concrete creep deformation were analyzed, which can be used to describe the creep behavior and whole creep process of the deep tunnel support structure. The combined model is characterized by a visco-elasto-plastic deviatoric behavior and an elasto-plastic volumetric behavior. The viscoelastic constitutive law corresponds to a Burger model, and the plastic constitutive law corresponds to a Mohr-Coulomb model. The characteristics of viscoelastic plasticity can be described by the combined model. The problem which the typical Burgers model was only can be used to describe viscoelasticity creep is resolved perfectly. In addition, the methods to solve triaxial compression creep model parameters are given and the parameters of supports for deep tunnel are determined to analyze the stability of surrounding rock.⑤Shear strain time series of several typical points which placed in the tunnel at deep hard rock location are selected to reconstruct phase space. Some nonlinear dynamics indexes （largest Lyapunov exponents and Kolmogorov entropy） are calculated to study the deformation heterogeneity in evolution process of excavation and the nonlinear stability of surrounding rock. And the evolution of surrounding rock system at chaotic state is sensitive to initial conditions.⑥The deformation features of surrounding rock in deep hard rock tunnel are analyzed after long-term monitoring measurement. It is fund that the deformation features are different greatly from shallow tunnel. By applying whole domain method,local region method and mixed optimizing model（chaotic reconstruct phase space mixed with Gray Model）to the engineering, the deformation of surrounding rock is predicted and the results of these displacement-predicting models agree well with the measured results. In addition, analysis is made about the comparison prediction results with every method to discuss the comprehensive error and precision.更多还原