煤炭科学技术2024,Vol.52Issue(12) :71-83.DOI:10.12438/cst.2023-1566

含共面双裂隙复合岩三轴力学行为及能量演化规律

Study on triaxial mechanical behavior and energy evolution of composite rock with coplanar double fractures

司余洁 肖桃李 袁浩 折海成 赵云峰
煤炭科学技术2024,Vol.52Issue(12) :71-83.DOI:10.12438/cst.2023-1566

含共面双裂隙复合岩三轴力学行为及能量演化规律

Study on triaxial mechanical behavior and energy evolution of composite rock with coplanar double fractures

司余洁 1肖桃李 1袁浩 2折海成 1赵云峰1
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作者信息

  • 1. 长江大学城市建设学院,湖北 荆州 434023
  • 2. 长江大学城市建设学院,湖北 荆州 434023;西南交通大学土木工程学院,四川 成都 610031
  • 折叠

摘要

大量深部岩体工程中广泛存在着不同性质岩石相互接触,局部构成了典型的复合岩体,而裂隙构型属性和围压对复合岩力学行为、能量演化及裂纹扩展规律都有着显著影响.为了研究裂隙构型属性和围压对复合岩力学行为、能量及微裂纹演化规律的影响,基于室内单轴和三轴压缩试验,采用离散元软件构建含共面双裂隙复合岩三轴压缩颗粒模型,系统研究了复合岩在不同裂隙倾角、长度和围压下的力学行为、能量及微裂纹的演化规律.研究结果表明:①裂隙倾角和围压的增加对岩样的力学特性有着优化作用,裂隙长度的增加对其有着劣化作用,且复合岩从单向受力转变为三向受力时,力学特性发生骤变,得到显著的优化;②随着裂隙倾角、长度及围压的增加,复合岩能量大小分别呈现"U"形分布、递减和递增的变化规律,能量的损耗主要出现在损伤应力以后;③岩样在变形加载过程中,产生的微裂纹以张拉裂纹为主,剪切裂纹主要出现在损伤应力后,裂隙几何参数和围压主要影响在相同应力阈值时的微裂纹演化特性.

Abstract

In a large number of deep rock mass engineering,there is widespread contact between rocks with different properties,forming typical composite rock masses locally.The fracture configuration properties and confining pressure have a significant impact on the mech-anical behavior,energy evolution,and crack propagation law of composite rock.In order to study the effects of fracture configuration properties and confining pressure on the mechanical behavior,energy,and microcrackevolution of composite rock,based on indoor uniaxi-al and triaxial compression tests,a triaxial compression particle model of composite rock with coplanar double fractures was established by using discrete element numerical simulation software,and the mechanical behavior,energy,and microcrack evolution of composite rock under different fracture inclination,length and confining pressure were systematically studied.The results indicate that:①The increase of fracture inclination angle and confining pressure has an optimization effect on the mechanical properties of the rock sample,and the in-crease of fracture length has a deterioration effect on it.In addition,when the composite rock changes from unidirectional stress to three-directional stress,the mechanical properties change sharply and are significantly optimized.②With the increase of fracture inclination,length and confining pressure,the energy of composite rock presents a U-shaped distribution,decreasing and increasing law respectively,and the energy loss mainly occurs after the damage stress.③During the deformation and loading process of rock samples,the micro-cracks generated are mainly tensile cracks,while shear cracks mainly occur after damage stress.The geometric parameters of fracture and confining pressure mainly affect the evolution characteristics of microcracks at the same stress threshold.

关键词

离散元/复合岩/共面裂隙/力学特性/能量特征/微裂纹

Key words

Discrete element/Composite rock/Coplanar crack/Mechanical properties/Energy characteristics/Microcracks

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出版年

2024
煤炭科学技术
煤炭科学研究总院

煤炭科学技术

CSTPCDCSCD北大核心
影响因子:2.095
ISSN:0253-2336
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