Strength criterion for crystalline rocks considering grain size effect and tensile-compressive strength ratio

The macroscopic mechanical properties of rocks are significantly influenced by their microstructure.As a material bonded by mineral grains,the grain morphology of crystalline rock is the primary factor influencing the strength.However,most strength criteria neglect the strength variations caused by different grain characteristics in rocks.Furthermore,the traditional linear criteria tend to overestimate tensile strength and exhibit apex singularity.To address these shortcomings,a piecewise strength criterion that considers the grain size effect has been proposed.A part of an ellipse was employed to construct the envelope of the tensive-shear region on the meridian plane,to accurately reproduce the low tensile-compressive strength ratio.Based on the analysis of experimental data,both linear and exponential modification functions that account for grain size effects were integrated into the proposed criterion.The corresponding finite element algorithm has been implemented.The accuracy and applicability of the proposed criterion were validated by comparing with the experimental data.

连续型和阶梯型不均匀沉降作用下建筑结构响应的数值分析

在采矿活动频繁的地区,建筑物不均匀沉降和矿震经常发生。这种现象可归因于采矿活动造成的地基变形和内力的重新分布,这往往导致建筑物结构受到严重破坏。露天矿关闭后边坡的长期变形导致了周围建筑物的不均匀沉降。针对这些问题,本文提出了四种非均匀沉降模型,并分析了不同建筑模型的静动力响应特性。数值模拟结果表明,阶梯沉降框架-剪力墙结构在静力分析中表现出较好的性能,而连续沉降框架结构在安全评价中缺乏足够的支撑。此外,小于3.0M的矿震对附近建筑物的影响可以忽略不计。研究结果可为矿山工业城市建筑沉降和矿山震害分析提供参考。