| 西藏贡觉粉砂质泥岩工程地质特性与蠕变强度研究 |
| |
| 引用本文： | 郭长宝,王磊,李任杰,吉锋,王炀,严孝海,刘贵.西藏贡觉粉砂质泥岩工程地质特性与蠕变强度研究[J].水文地质工程地质,2021,48(5):54-64. |
| |
| 作者姓名： | 郭长宝 王磊 李任杰 吉锋 王炀 严孝海 刘贵 |
| |
| 作者单位： | 1.中国地质科学院地质力学研究所，北京 100081 |
| |
| 基金项目： | 中国地质调查局地质调查项目（DD20190319；20190505）；国家自然科学基金项目（41877279；41731287；41941017）；自然资源部杰出青年科技人才项目（12110600000018003911） |
| |
| 摘 要： | 川藏铁路在穿越西藏贡觉地区时遇到三叠系粉砂质泥岩，在高地应力条件下容易发生大变形等危害。文章开展了不同围压下的岩石三轴压缩和和三轴蠕变试验，结合PFC数值模拟，研究了粉砂质泥岩在不同围压下的蠕变特性和长期强度研究，结果表明:贡觉粉砂质泥岩流变具有西原蠕变模型特征，蠕变与常规三轴试验条件下，随着围压不断增大，粉砂质泥岩试样均由拉-剪破坏向单剪破坏过渡，剪切破裂面与水平线的夹角逐渐减小，微裂纹数量减少；蠕变试验相较于常规三轴试验，由拉应力引起的压碎带影响范围更广；在高围压条件下，粉砂质泥岩更容易发生流变，随着围压的增大，轴向应变、侧向应变和体积应变均增大，微裂纹数量呈下降趋势；瞬时弹性模量及黏弹性系数与围压呈线性递增关系，黏弹性模量与围压呈对数型增长关系，黏塑性系数与围压呈指数型增长关系。在荷载长期作用下，岩石长期强度低于瞬时强度。
|
| 关 键 词： | 川藏铁路 粉砂质泥岩 三轴压缩蠕变试验 变形机理 数值模拟 |
| 收稿时间： | 2021-06-20 |
Engineering geology properties and creeping strength characteristics of the silty mudstone in Gongjue County in Tibet of China |
| |
| Affiliation: | 1.Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China2.Key Laboratory of Active Tectonics and Geological Safety, Ministry of Natural Resources, Beijing 100081, China3.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, Sichuan 610059, China |
| |
| Abstract: | The Triassic silty mudstone is encountered in the Sichuan-Tibet Railway, when it passes through Gongjue County in Tibet of Chian, and the rock is prone to cause large deformation under the condition of high geo-stress. In this study, we carried out the triaxial rock compression and triaxial creep tests under different confining pressures. Combined with the PFC numerical simulation, we have also studied the creeping characteristics and long-term strength of the silty mudstone under different confining pressures. The results show that the rheology of the Gongjue silty mudstone is characterized by the Nishihara creep model. With the continuous increase of the confining pressure, under the conditions of the creep and conventional triaxial tests, the silty mudstone specimens all undergo transition from tensile-shear failure to single-shear failure. The angle between the shear fracture surface and the horizontal line gradually decreases, and the number of microcracks decreases. Compared with the conventional triaxial test, the creep test has a wider range of influence on the crush zone caused by tensile stress. Under the conditions of high confining pressure, the silty mudstone is more prone to rheology. The numerical simulation results show that when the confining pressure increases, the axial strain, lateral strain and volumetric strain will increase, while the number of microcracks decrease. There is a linear increasing relationship between the instantaneous elastic modulus and the viscoelastic coefficient with the confining pressure, the viscoelastic modulus has a logarithmic growth relationship with the confining pressure, and the viscoplastic coefficient has an exponential growth relationship with the confining pressure. Under long-term loading, the long-term strength phase of the rock is lower than the instantaneous strength. |
| |
| Keywords: | |
|
| 点击此处可从《水文地质工程地质》浏览原始摘要信息 |
|
点击此处可从《水文地质工程地质》下载全文 |
|
