柱状节理岩体宏观等效弹性模量尺寸效应研究

以金沙江白鹤滩水电站工程为背景，结合相关的岩石力学试验方法，建立了柱状节理岩体三维离散元模型，对柱状节理岩体进行了三轴压缩试验数值模拟。数值试验研究了六棱柱形柱状节理岩体柱体直径变化、四棱柱形柱状节理岩体柱体边长、节理错距变化对其等效弹性模量的影响。为研究随机柱状节理岩体柱体尺寸对岩体等效弹性模量的影响，提出柱体大对角线长尺寸控制方案，并研究了柱体大对角线长变化对岩体等效弹性模量的影响。通过与现场试验的对比研究，结果表明：随机柱体尺寸控制方案可靠；柱体尺寸的变化对与柱体垂直方向的等效弹性模量影响较大，是主要影响因素；四棱柱形柱状节理岩体错距变化主要对与错距平行的岩体等效弹性模量产生影响，对其它两个方向的等效弹性模量的影响较弱，是次要影响因素。研究结果为工程实践中等效力学参数的确定提供了相关参考。

Research of size effect on equivalent elastic modulus of columnar jointed rock mass

Based on Baihetan Hydropower Project on Jinsha River,3D discrete element models for columnar jointed rock mass are established considering the relevant methods of rock mechanics.Numerical simulations of triaxial compression tests on the columnar jointed rock mass are carried out.The impacts of diameter change on the equivalent elastic modulus of hexagonal columnar jointed rock mass as well as those of side length and joint stagger change on the equivalent elastic modulus of quadrangular columnar jointed rock mass are studied.In order to investigate the impacts of size change on the equivalent elastic modulus of random columnar jointed rock mass,a program for controlling columnar size is proposed using the average large diagonal size.Then the impacts of change of the average large diagonal size on the equivalent elastic modulus are studied.It is shown from the researches on size effect and comparison with the in-situ tests that changes in cylinder size have larger impacts on the equivalent elastic modulus perpendicular to cylinder than on that parallel to cylinder.Changes in stagger of quadrangular columnar jointed rock mass mainly have impacts on the equivalent elastic modulus parallel to stagger and have weak impacts on the equivalent elastic moduli in two other directions.The results can provide reference for the determination of mechanical parameters in engineering practice.