应变率对红砂岩渐进破坏过程和特征应力的影响  

Influence of strain rate on progressive failure process and characteristic stresses of red sandstone

作　　者：王洪亮[1] 范鹏贤[1,2] 王明洋[1] 李文培[1] 钱岳红[1] 

机构地区：[1]解放军理工大学工程兵工程学院,南京210007 [2]中国矿业大学深部岩土力学与地下工程国家重点试验室,江苏徐州221008

出　　处：《岩土力学》2011年第5期1340-1346,共7页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划(973计划)项目(No.2010CB732003);水利部公益性行业科研专项项目(No.201001009);国家自然科学杰出青年基金(No.50825403);中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金项目(No.SKLGDUEK0907);国家自然科学基金创新研究群体科学基金(No.51021001)

摘　　要：为了深入研究脆性岩石的渐进破坏过程,利用RMT-150C型岩石力学试验系统对产自鲁南地区的一种红砂岩进行了系统的力学性质试验研究,得出该类型砂岩试样在不同应变率条件下的力学表现。将试件的渐进破坏过程通过特征应力分为裂纹闭合阶段、线弹性变形阶段、裂纹起裂和稳定扩展阶段以及裂纹不稳定扩展阶段,通过对应力-应变曲线、轴向变形刚度、体积应变曲线和裂纹体积应变等数据的分析,以及采用动点回归技术确定了试样的起裂应力和致损应力,并进一步研究了该类红砂岩的渐进破坏过程及红砂岩峰值强度、起裂应力等参数和应变率之间的关系。试验结果表明,随着应变率的增加,红砂岩试样的峰值强度先降低后提高,起裂应力及致损应力与峰值强度的比值均有所降低。分析了红砂岩峰值强度变化的物理机制并给出了解释,研究了应变率对红砂岩渐进破坏过程的影响。In order to investigate the progressive failure process of brittle rock,the mechanical properties of red sandstone from south area of Shandong province are studied by the RMT-150C rock mechanical experimental system.The stress-strain curves of samples under different strain rates are recorded.The deformation and progressive failure process of rock samples is divided into several stages,including crack closure stage,linear elastic deformation stage,crack initiation and stable crack growth stage and unstable crack growth stage.Then the crack initial stresses and crack damage stresses are determined by the moving point technique according to the data of stress-strain curves and other deduced data.The influence of strain rate on the ultimate critical strength,the crack initial stress and the crack damage stress are also investigated.The results show that the ultimate critical strength first decreases and then increases as the strain rate increases;and the rate of crack initial stress and crack damage with the ultimate critical strength decreases.The mechanism of the experimental results are analyzed and explained by the stress concentration model of rock with nonuniformities.And the influence of strain rate on the progressive failure process is studied.

关 键 词：红砂岩 应变率 力学性能 试验研究 

分 类 号：TU451[建筑科学—岩土工程]