Study of hidden factors affecting the mechanical behavior of soil–rock mixtures based on abstraction idea     

Dong  Hui  Peng  Bocheng  Gao  Qian-Feng  Hu  Yin  Jiang  Xiuzi 《Acta Geotechnica》2021,16(2):595-611

Because of spatial variability and complex compositions, the mechanical test results of natural soil–rock mixtures (SRMs) are often discrete and lack reproducibility, which has greatly restricted the practical application of the experimental findings. The objective of this study was to examine the general mechanical behavior of SRMs under the influences of some hidden factors (e.g., structural parameters, parent rock type and weathering degree). To that end, the abstraction idea was adopted to prepare purified SRM samples. Large-scale triaxial tests were performed on these purified materials. On this basis, the influences of three structural parameters on the mechanical behavior of SRMs were studied. Moreover, the relationship between the shear strength and parent rock type and that between the shear strength and the spatial distribution of rock blocks were quantified. Some additional intrinsic behavior was distinguished from individual experimental phenomena through the comparative analysis of the test data in this study and those reported in the literature. The results show that the hidden factors had significant influences on the mechanical behavior of SRMs. A greater saturated uniaxial compressive strength of rock blocks generally led to a larger shear strength of SRMs. According to the significance of their influences on the shear strength parameters of SRMs, the structural parameters are ordered as: the gradation of rock blocks, the initial dry density of sample and the spatial distribution of rock blocks. The deformation and failure feature of SRMs were considerably affected by the spatial distribution of rock blocks and shear rate. And the shear strength parameters of SRMs were mainly influenced by the content of grains between 40 and 60 mm. The findings of this study would provide useful guidance for engineering practice.

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基于非线性损伤理论的改进CVISC模型及其在FLAC3D中实现          下载免费PDF全文

蒋树  文宝萍  蒋秀姿  李瑞冬  赵成 《水文地质工程地质》2019,(1):56-56

滑坡形成是一个典型的岩土变形破坏时效过程,低速滑坡时效过程尤为显著。基于流变理论,建立反映滑坡变形破坏发展过程的本构模型、预测滑坡活动趋势,一直是国内外滑坡研究的基本途径和难点问题之一。然而,目前国内外已有的多数流变模型仅能反映滑坡岩土蠕变的第一、第二阶段,不能刻画滑坡岩土蠕变的第三阶段（加速蠕变阶段）。本文基于滑带在滑坡中的作用以及滑带岩土剪切蠕变发展的累进性和非线性特征,借助损伤理论,在FLAC3D内置的CVISC流变本构模型中引入非线性损伤黏塑性元件,构建了可描述滑坡加速蠕变过程的非线性损伤流变本构模型,依据类比原理建立了改进的CVISC三维差分模型,通过FLAC3D开放的用户接口实现了本构模型的二次开发,并将改进的CVISC模型用于长期缓慢滑移、伴随间歇性剧烈活动的甘肃舟曲泄流坡数值模拟中。模拟结果显示,该模型不仅呈现了滑坡的加速蠕变特征,而且揭示的滑坡活动特征与其曾经出现的活动特征基本一致,从而证实基于非线性损伤理论的改进CVISC模型具有较好的有效性。  相似文献   

苏南宁镇地区震旦纪至白垩纪的岩石力学性质的系统测试数据浅析          下载免费PDF全文

孙岩  沈修志  黄钟瑾  张庆龙 《地质科学》1985,(3):301-307

苏南宁镇地区,震旦系至第四系出露完整,研究程度颇深,诸地层的不同特征,以作为华南各地区地层对比之标准而著称。近几年来,随着大规模勘探工作的进行,宁镇地区地层的物性参数、电性参数和力学参数等各种资料,均在不断完善之中。本文试以该区震旦系至白垩系地层的岩石单轴抗压强度等的系统测试数据,对其有关的岩石力学特性进行粗浅地分析。  相似文献   

Preliminary analysis of some chemically determined data from the compressive fault zone at Dayu,Jiangxi province     

Yan Sun  Xiuzi Shen  Shouhe Liu 《中国地球化学学报》1984,3(3):285-294

Discussed in this paper are the relationship between the compressive fault zone and mineralization, and the regularities governing the concentration-dispersion of elements in the compressive fault zone based on chemically determined data from field and laboratory studies of megascopic structures and tectonites. Horizontal zoning has been recognized in the compressive fault zone, with four distinct belts from the centre outwards. Four groups of chemical components in these four belts are distinguished: the first group-SiO₂, FeO, MgO and MnO; the second-Fe₂O₃, Na₂O and K₂O; the third-CaO and A1₂O₃; and the fourth-TiO₂ and P₂O₅ Furthermore, various tectono-geochemical processes (including dynamic differentiation or mechanical metamorphic differentiation, dynamothermal metamorphism, oxidation-reduction, and hydrolysis-dewatering) in the fault zone are also discussed in detail.  相似文献