砂岩强度的动态尺寸效应机理研究  

Study on the Mechanism of Dynamic Size Effect on the Strength of Sandstone

作　　者：罗伊 戚承志[1,2] 盛志刚 王泽帆 赵发 Luo Yi;Qi Chengzhi;Sheng Zhigang;Wang Zefan;Zhao Fa(Beijing Future Urban Design Advanced Innovation Center,Beijing University of Civil Engineering and Architecture,Beijing 100044,P.R.China;Beijing International Cooperation Base for Urban Transport Infrastructure Construction,Beijing University of Civil Engineering and Architecture,Beijing 100044,P.R.China;Faculty of Civil Engineering,Institute of Disaster Prevention,Beijing 101601,P.R.China;Faculty of Architecture,Civil and Transportation Engineering,Beijing University of Technology,Beijing 100124,P.R.China)

机构地区：[1]北京建筑大学北京未来城市设计高精尖创新中心,北京100044 [2]北京建筑大学北京城市交通基础设施建设国际合作基地,北京100044 [3]防灾科技学院土木工程学院,北京101601 [4]北京工业大学城市建设学部,北京100124

出　　处：《地下空间与工程学报》2024年第5期1442-1453,共12页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(12172036,51774018);长江学者创新团队项目(IRT_17R06)。

摘　　要：试验研究发现岩石强度的动态尺寸效应与静态尺寸效应相反,但岩石动态尺寸效应的内在微细观动力机理还没有澄清。本文以砂岩为例,基于岩石的翼状裂纹模型,联合求解裂纹的加载方程和运动方程,研究了在动载作用下试件尺寸对岩石强度的影响机理,即岩石强度的动态尺寸效应。结果表明:在相同动力加载率条件下,试件尺寸越大,裂纹连接所需要的时间越长;试件破坏时的施加的应力(也即动态强度)越大,试件的动态尺寸效应越显著,岩石动态强度近似以幂律关系增长;对于一定的试件尺寸范围,根据数值分析,得到岩石的临界应变率范围,在该临界应变率以下,静态的尺寸效应占主导地位,在该临界应变率以上,动态尺寸效应占主导地位,且临界应变率随试件尺寸增加而降低;试件临界尺寸随着应变率增加而降低。Experimental studies show that the dynamic size effect is opposite to the static size effect of rock strength,but the intrinsic micro-dynamic mechanism of the dynamic size effect of rocks has not been clarified yet.In this paper,sandstone sample is selected as the research object,and based on the wing-crack model of rock,the crack motion equation and loading equation of sample are jointly calculated,the mechanism of rock specimen size on strength under dynamic loading,namely the dynamic size effect of rock strength is analyzed.The results show that:Under the same dynamic loading rate,with the larger the specimen size,more time is required for crack coalescence,and the applied stress at the moment of the specimen failure(dynamic strength)is greater,the dynamic size effect is more evident,and the rock dynamic strength increases with strain rate approximately in a power law;The critical strain rate range at a definite size range of specimen of rock is obtained by numerical calculation,and the static size effect takes the dominant position when the strain rate is below the critical strain rate,while the dynamic size effect dominates when the strain rate is above the critical strain rate,and the critical strain rate decreases with the increase of specimen size;The critical size of the specimen decreases with the increase of the strain rate.

关 键 词：动态尺寸效应 翼状裂纹模型 动力强度 临界应变率 

分 类 号：TU452[建筑科学—岩土工程]