平台中心角对岩石抗拉强度测定影响的数值分析  

Numerical analysis of influence of central angle of flats on tensile strength of granite in split test with flattened disk

作　　者：于庆磊[1] 唐春安[2] 杨天鸿[1] 唐世斌[2] 刘洪磊[1] 

机构地区：[1]东北大学资源与土木工程学院,沈阳110004 [2]大连理工大学土木水利学院,大连116024

出　　处：《岩土力学》2008年第12期3251-3255,3260,共6页Rock and Soil Mechanics

基　　金：国家自然科学基金重点资助项目(No.40638040);国家自然科学基金资助项目(No.50674025)

摘　　要：岩石抗拉强度是岩石的一个重要力学参数,在测试岩石抗拉强度的平台巴西盘劈裂试验中,平台中心角对测试结果会产生重要影响,但测试中对此角度尚无严格规定,从而造成抗拉强度测试结果有很大的离散性。从细观的角度着手,应用数字图像技术对岩石材料内部不同细观介质的空间分布进行精确测量和数值表达,建立与有限元网格之间的相互映射关系,并引入到原有的岩石破坏过程分析系统RFPA中,建立了能反映岩石非均匀性的平台巴西盘数值模型。通过对花岗岩断面图像进行处理,运用数值模型研究了平台中心角对平台巴西盘轴线应力分布、劈裂破坏模式和抗拉强度测定的影响,确定平台中心角的合理值应在20～30°的范围内,这与试验结果相一致,从机制上进一步分析验证了平台中心角的取值范围,为测试中平台中心角的选取提供了理论依据。Tensile strength is an important mechanical property of rock. In Brazil test of a flattened disk specimen measuring tensile strength of rock, the central angle of the flats has great influence on measuring tensile strength. But there is no restriction in the test, which makes tensile strength of rock obtained by the test very scattering. Digital image processing methods are used as a measurement tool to construct a numerical representation for the actual spatial distribution of different materials and components in rock samples, which is introduced into rock failure process analysis （RFPA2D）, and numerical model of Brazil tests of granite flattened Brazilian disk specimen which considers the actual heterogeneity is established by processing its digital image. Using the numerical model, the influences of central angle of flats on stress distribution along axial line, splitting failure modes and tensile strength are analyzed; and reasonable range of central angle of flats is obtained, which should be in the range of 20°-30°.

关 键 词：数字图像 平台巴西盘 抗拉强度 数值试验 平台中心角 

分 类 号：TU458[建筑科学—岩土工程]