【作者】 赵宝云；

【导师】 刘东燕；

【作者基本信息】 重庆大学 ， 土木工程， 2011， 博士

【摘要】 岩石的蠕变是岩石类材料重要的工程特性,是研究岩石流变力学最为重要的内容之一。在多数情况下,岩石工程特别是大型地下洞室因开挖施工引起的围岩变形失稳破坏与岩石的蠕变有着密切的联系,由岩石蠕变引起的实际工程问题已得到国内外众多学者的广泛关注,并取得了很大的进展,特别是在利用实测试验资料反演蠕变模型的参数,进而应用到工程预测等领域。但是岩石蠕变理论、蠕变试验以及蠕变特性工程应用等方面至今尚未形成完整的理论体系,特别是岩石在拉、压应力条件下的蠕变特性与本构模型仍是研究的重点和难点问题。为此,本文在研究现有岩石蠕变特性研究成果的基础上,采用试验研究、理论分析与数值模拟计算相结合的方法,基于岩石单轴直接拉伸蠕变、单轴压缩蠕变以及三轴压缩蠕变试验,运用岩石非线性理论,探讨了岩石的蠕变特性,建立了岩石非线性拉、压蠕变模型,并将岩石蠕变特性的研究成果应用到地下大空间洞室的施工控制当中。论文的主要研究工作如下:①设计加工了岩石单轴直接拉伸试验仪,应用该试验仪和岩石材料刚性伺服试验机(MTS)对红砂岩的单轴拉伸、单轴压缩以及三轴压缩等瞬时力学特性进行了研究,分析了岩石瞬时拉、压变形规律,获得了拉、压作用下的瞬时力学参数,探讨了压缩作用下岩石屈服强度,比较了两种不同尺寸标准试件单轴压缩作用下的强度特性,分析了不同力学响应机制下岩石瞬时破坏的机理。②采用自行设计加工的岩石挂重型直接拉伸蠕变仪以及实验室岩石全自动流变伺服仪,对红砂岩进行了单轴直接拉伸、单轴压缩以及三轴压缩蠕变试验,研究单轴直接作用下岩石轴向应变以及侧向应变随时间变化的规律以及压缩条件下岩石轴向变形随时间变化的规律,探讨了各力学响应机制下蠕变速率的变化趋势。为更好的认识岩石拉、压蠕变机理,对红砂岩蠕变进行了短时、长时以及卸荷蠕变特性试验分析,得到了拉伸作用下岩石的长期强度变化规律。③基于岩石拉、压蠕变试验结果,比较H-K模型与Burgers蠕变模型得出Burgers蠕变模型能更好地反映荷载小于岩石长期强度(短时压缩蠕变为屈服强度)时的岩石蠕变特性。基于岩石拉、压作用下加速蠕变试验结果,推导了可表示岩石加速蠕变特性的二元件粘塑性模型的非线性本构,将该模型与Burgers蠕变模型串联建立了一个新的岩石非线性粘弹塑性拉、压蠕变模型。介绍了该非线性粘弹塑性蠕变模型在拉、压应力状态下的蠕变特征,并采用基于MATLAB程序的quasi-Newton算法(BFGS算法)对红砂岩拉、压状态下的蠕变全过程试验曲线进行了参数的直接辨识。④基于拉格朗日有限差分理论,推导了非线性粘弹塑性拉、压蠕变模型的有限差分形式,以Mohr-Coulomb为屈服准则并结合FLAC3D良好的二次开发环境对构建的非线性粘弹塑性拉、压蠕变模型的进行了二次开发研究。通过拉、压蠕变试验与该模型模拟试验对比验证了模型二次开发的正确性,并结合工程实例现场监测、Cvisc模型模拟计算、Mohr-Coulomb本构模拟计算与该模型计算结果对比验证了非线性粘弹塑性拉、压蠕变模型的工程适用性。⑤将非线性粘弹塑性拉、压蠕变模型应用于深圳市某地三连拱地下水工泵站蓄水池施工控制当中,讨论了最佳开挖支护方案,分析了最佳开挖方案下施工过程中围岩变形稳定性和支护结构的变形及受力特性,探讨了最优的施工方案以及最佳方案下的合理支护时机,为岩石工程的长期稳定与安全性提供了合理的评价与建议。更多还原

【Abstract】 Creep is one of the most important mechanical properties to the study the rock rheology in rock mass material. In most cases, the deformation instability and failure of rock engineering is closely related to the rock creep behaviors, the practical engineering problem that caused by creep of rock has been widely concerned by many scholars at home and abroad, and achieved great progress, particularly in the that used by measured test data and then apply to the project forecast. But the creep theory, creep test instruments and the creep properties of engineering applications today is not very perfect, and construction of many major projects have still posed a serious challenge for study of rock creep, especially in rock rheological properties that under tension and compression and constitutive model still is the key study point and hot issue.In view of this, based on the well known research achievements this thesis will use a combination method including experimental research, theoretical analysis and numerical simulation. Based on uniaxial direct tensile creep test, uniaxial compression and triaxial compression creep tests; the non-linear theory was used to study the creep characteristics of the rock and established a non-linear tensile and compressive creep model. Results of creep mechanical properties were applied to the construction control of large underground arch cavern.In this dissertation, the main investigation work foruses on the following:①Designed and fabricated a rock direct tensile testing device, based on this device and rock materials serving compression machine, the uniaxial direct tension, uniaxial compression and triaxial compression short-term mechanical characteristics of red sandstone were studied, analysis of the law of rock deformation under direct tensile and compressive, discussed the yield strength under compression, compares uniaxial compression strength properties of two kinds of different measurement standard specimens, the short-term mechanical parameters of rocks under tension and compression has been obtained, finally, the mechanical short-term failure mechanism under corresponding mechanisms was analyzed.②The self-designed and developed rock hang weight type directly creep instrument and laboratory rock rheology automatic servo device were used to test the direct uniaxial tension, uniaxial compression and triaxial compression creep of red sandstone. The law of axial strain and lateral strain under direct uniaxial tension and the axial deformation of rocks under compression were studied. The creep rate under corresponding mechanism was also discussed. To better understand the mechanism of rock tensile and compressive creep, the creep was short-term, long-term and unloading creep behaviors of red sandstone were analysis, obtained t the long-term tensile strength.③Based on the rock tension and compression creep test results this dissertation compared with HK model and Burgers creep model and obtained that Burgers creep model can reflect rock creep characteristics which load is less than the long-term strength of rock (short-term creep compression is yield strength). And on the basis of the rock tension and compression accelerated creep results it was deduced two elements nonlinear visco-plastic constitutive mode that can be better reflect accelerated creep of rock, the model and the Burgers creep model series established a nonlinear visco-elastic plastic creep model. The creep behaviors of the nonlinear visco-elastic plastic creep mode in tension and compression stress was studied, and red sandstone under tension and compression creep test curve parameters were directly identified by MATLAB program which based on quasi-Newton algorithm (BFGS algorithm).④Based on Lagrangian finite difference theory this dissertation derived the finite difference form of nonlinear visco-elastic plastic creep the model which in tension and compression. The Mohr-Coulomb yield criterion was used to the establishment a complex non-linear visco-elastic plastic model in tension and compression, and combined with secondary development environment of FLAC3D the composite model was secondary developed. By tension and compression creep test and composite model to simulate experimental verified the correctness of the model secondary development. Later, comparison with monitoring results, the Cvisc model simulation calculate results and Mohr-Coulomb constitutive model calculate results of an engineering example, the applicability of the nonlinear visco-elastic plastic model was verified.⑤The composite tensile and compressive nonlinear visco-elastic plastic creep model is applied to construction control of the three-arch cavern of groundwater reservoir pumping stations that located in a certain place in Shenzhen, the stability of surrounding rock deformation during excavation and supporting structure deformation and carrying capability were analyzed. Finally, the long-term stability of rock engineering under complex stress state is predicted, which brings forward reasonable evaluation and suggestion for long-term stability and safety of rock engineering.更多还原