摘要
岩石脆性是表征岩石破坏特征的重要参数,建立准确的脆性评价方法对岩土工程具有重要意义。本文总结了目前国内外常用的基于应力-应变曲线表征岩石脆性的方法,并探讨了其适用性,同时采用3种岩石分析了岩石破裂过程中峰前与峰后能量演化规律及脆性指标。研究结果表明:单轴压缩条件下粉砂岩、大理岩和花岗岩耗散能演化规律分别呈现“■”型、“S”型和“L”型;大理岩峰前脆性指数最小,花岗岩最大,峰后脆性指标粉砂岩和花岗岩相同,大理岩最小;利用全应力-应变曲线,基于能量演化角度,可以较好地表征岩石破裂过程中峰前和峰后的脆性特征,但脆性表征指数不能简单地通过数学计算将峰前和峰后指标合并为一个指标;峰前和峰后岩石脆性指数的关联性尚不明确,合并的脆性指标无法同时有效表征峰前和峰后脆性变化规律,应分别考虑峰前和峰后脆性指标,单独表征分析岩石峰前和峰后的脆性特征和规律。
Rock brittleness is an important parameter to characterize failure characteristics of rocks.An accurate brittleness evaluation method is of great significance to geotechnical engineering.In the present study,we primarily summarized a considerable number of methods that were widely used to characterize rock brittleness based on the stress-strain curve.Then,three types of rocks were used to analyze the energy evolution law and brittleness index of the pre-peak and post-peak during rock failure.The results indicate that the dissipative energy evolution law of sandstone,marble,and granite specimens under uniaxial compression presents“C”type,“S”type,and“L”type respectively;At the pre-peak stage,the brittleness index of marble is the smallest and that of the granite is the largest;At the post-peak stage,the brittleness index of sandstone is the same as that of granite,and that of marble is the smallest;The full stress-strain curve can better characterize the brittleness pre-peak and post-peak in the process of rock failure based on the energy evolution.While the pre-peak and post-peak indexes cannot be simply mathematically characterized into one index.The correlation between the pre-peak and post-peak rock brittleness indexes is not clear.The combined brittleness index cannot effectively characterize the change of the pre-peak and post-peak brittleness at the same time.Pre-peak and post-peak brittleness indexes should be separately considered.The brittleness characteristics and laws of the pre-peak and post-peak should be separately characterized and analyzed.
作者
张旗
张晓平
常鑫
刘重羊
ZHANG Qi;ZHANG Xiaoping;CHANG Xin;LIU Chongyang(School of Civil Engineering,Wuhan University,Wuhan 430072,China;Key Laboratory of Geotechnical and Structural Engineering Safety of Hubei Province,Wuhan University,Wuhan 430072,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)
出处
《工程地质学报》
CSCD
北大核心
2024年第6期2110-2119,共10页
Journal of Engineering Geology
基金
国家自然科学基金项目(资助号:52108382,51978541)
岩土力学与工程国家重点实验室开放基金课题(资助号:Z020022)
中央高校基本科研业务费专项(资助号:2021BCA154)。
关键词
岩石
应力-应变曲线
能量演化
弹性能
耗散能
脆性评价
Rock
Stress-strain curve
Energy evolution
Elastic energy
Dissipation energy
Brittleness evaluation
作者简介
第一作者:张旗(1989-),男,博士,副研究员,主要从事岩石破裂过程及震源机制反演等研究工作.E-mail:zhqi@whu.edu.cn;通讯作者:张晓平(1982-),男,博士,教授,博士生导师,主要从事岩石力学、工程地质及地下工程等方面的研究工作.E-mail:jxhkzhang@163.com。
