基于离散元的柱状节理岩体等效弹性模量尺寸效应研究  

SCALE EFFECT ON EQUIVALENT CONTINUUM ELASTIC MODULUS OF COLUMNAR JOINTED ROCK MASSES BY DISTINCT ELEMENT METHOD

作　　者：倪海江[1,2] 徐卫亚[1,2] 石安池[3] 徐建荣[3] 吉华[1,2] 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,南京210098 [2]河海大学岩土工程科学研究所,南京210098 [3]中国水电顾问集团华东勘测设计研究院有限公司,杭州310014

出　　处：《工程力学》2015年第3期90-96,共7页Engineering Mechanics

基　　金：国家科技支撑计划项目(2013BAB06B01);国家自然科学基金;法国国家科研署联合基金项目(50911130366)

摘　　要：尺寸效应的研究在评估节理/裂隙岩体力学性质方面具有重要意义,通过离散元数值方法研究尺寸效应。引入Voronoi图模拟随机节理,以相对标准差为标准,衡量试验结果的稳定性和可靠度,进行了足够次数不同尺寸的单轴压缩数值试验。进而采用统计方法分析Eeq(等效弹性模量)和1/Eeq(等效柔量)的尺寸效应。研究表明:相对标准差值为5%对应的变形REV(representative elementary volume)尺寸约为4倍Voronoi多边形平均边长;样本Eeq的均值随着尺寸的增大显著降低,而样本1/Eeq的均值随尺寸变化很小。对结论的适用性进行了分析,实际工程中多采用样本Eeq的均值估算岩体的整体等效弹性模量,建议同时采用1/Eeq均值的倒数估算其下限。并将此方法应用于白鹤滩水电站节理岩体原位变形试验成果的分析。Scale effects play an important role in evaluating mechanical properties of jointed/fractured rock masses. These phenomena were studied through use of the distinct element method. The Voronoi diagram was introduced to simulate stochastic joints, and the coefficient of variation(CV) was used to estimate the resolution of a certain property from numerical tests. A large number of numerical tests with different geometric sizes were carried out. Then, the scale effects of equivalent continuum elastic modulus, Eeq and equivalent continuum elastic compliance, 1/Eeq were statistically analyzed. The investigation shows that: the estimated deformation REV size is about 4 times of average side length of a Voronoi polygon with acceptable variations for CV of 5%; the mean value of specimen's Eeq obviously decreases as size increases, and the mean value of specimen's 1/Eeq increases slightly with increasing size. In discussing the applicability of the results, it is better to adopt the reciprocal of a mean specimen's 1/Eeq as the lower bound of Eeq, while the mean specimen's Eeq should be used as the effective Eeq in engineering. This method was finally applied to analysis deformation data from in situ tests of Baihetan Hydropower Station.

关 键 词：岩石力学 尺寸效应 离散元 表征单元体积(REV) 弹性模量 节理/裂隙岩体 

分 类 号：TU45[建筑科学—岩土工程]