冻结粗粒砂岩和中粒砂岩的力学行为及能量演化机制
Mechanical properties and energy-dissipation mechanism of frozen coarse-grained and medium-grained sandstones
屈永龙 1杨更社 2奚家米 2倪万魁 3丁潇 4吴丙权3
作者信息
- 1. School of Civil and Architecture Engineering,Xi'an Technological University,Xi'an 710021,China;School of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China
- 2. School of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China
- 3. College of Geology Engineering and Geomatics,Chang'an University,Xi'an 710054,China
- 4. School of Civil and Architecture Engineering,Xi'an Technological University,Xi'an 710021,China
- 折叠
摘要
复杂地应力和低温环境条件下白垩系弱胶结红砂岩的力学特性和变形本质是西北地区冻结井筒工程安全建设的关键.通过低温单轴和三轴压缩试验,研究了不同低温、不同围压条件下饱和白垩系粗粒砂岩和中粒砂岩的强度和变形特性,查明了冻结砂岩加载变形过程中的能量演化规律和影响因素,并基于扫描电镜(SEM)揭示了两种砂岩的微观结构特征.结果表明:冻结白垩系砂岩的应力-应变关系呈应变软化型,其受温度、围压和岩性的影响显著,具有明显的孔隙压密变形阶段;冻结砂岩的三轴压缩强度随着温度和围压的增加分别呈非线性减小和增大规律,且各因素之间相互影响.两种砂岩的弹性模量随着温度的降低而非线性增大,但泊松比的变化与之相反.此外,冻结白垩系弱胶结红砂岩的总应变能、弹性能和耗散能具有不同的演化规律,揭示了冻结砂岩的变形破坏内部机制;基于能量比提出了冻结砂岩的损伤因子,评价了两种冻结砂岩的损伤力学特征.最后,从宏观物理特性和微观结构特征等多角度解释了两种砂岩力学和能量特性差异的内在原因.研究成果将为我国寒区矿山建设和深部地下工程的稳定性控制提供理论依据.
Abstract
Mechanical behavior and deformation essence of frozen soft rock under complex environmental conditions is crucial for frozen shaft engineering.The strength and deformation properties of sandstones under different low temperatures were investigated by conducting uniaxial and triaxial compression tests.The energy characteristics of rocks during the deformation were analyzed.The micro-structure features were obtained by scanning electron microscopy(SEM)test.The results show that the sandstones have a noticeable pore compression stage and the medium-grained sandstone is more pronounced.The rock strength decreases and increases non-linearly with the increase of temperature and confining stress,respectively,and the factors affect each other.The elastic modulus increases with the decrease of low temperature,while the changes in Poisson ratio is opposite.In addition,the total strain energy,elastic energy and dissipated energy of sandstones have different evolution laws,revealing the deformation and damage mechanism of rocks.Last,the internal reason of differences in the mechanical properties of sandstones is explained from the micro-structural perspective.The above research conclusions could provide a certain theoretical basis for the stability control of shaft engineering in northwest China.
关键词
冻结砂岩/低温/力学特性/能量演化/内部机制Key words
frozen sandstone/low temperature/mechanical property/energy evolution/internal mechanism引用本文复制引用
基金项目
National Natural Science Foundation of China(51774231)
Natural Science Basic Research Program of Shaanxi,China(2022JQ-443)
Scientific Research Program Funded by Shaanxi Provincial Education Department,China(22JK0416)
出版年
2023
NETL
NSTL
维普
万方数据