大孤山尾矿中砂力学特性研究

发布时间：2018-04-03 20:37

本文选题：邓肯-张模型　切入点：应力路径　出处：《辽宁科技大学》2017年硕士论文

【摘要】：砂土等岩土类材料主要由大量的颗粒物质所组成,在微观上颗粒形状、大小和位置随机分布的不均匀性,反映在宏观上则表现出压硬性,剪胀与各向异性等力学性质。对于砂土的力学性质的研究方面尽管许多学者已经做了大量的研究,但是尾矿砂在不同应力路径试验下的力学特性的试验研究还比较少。以鞍钢集团矿业公司大孤山选矿厂尾矿库中砂为研究对象,通过三轴试验研究了中砂在不同应力路径下应力应变关系的变化规律。开展的主要工作及其结论有:(1)论述和分析国内外关于砂土及尾矿在不同应力路径下力学性能的研究现状。(2)试验采用SLB-1三轴仪,分别在不同围压下对大孤山尾矿库中砂进行不固结和固结的不排水三轴试验,根据不同围压下的试验数据绘制出应力-应变曲线以及应力路径曲线。在相同围压下,固结完成的中砂强度比未固结的强度提高较大,亦即固结度对中砂的强度影响比较显著。并且同一应力路径的不同围压对中砂的强度是有影响的。在固结不排水应力路径试验中,对不同围压下的孔隙水压力随轴应变的变化亦是先增加到峰值,随即下降并产生负压。(3)利用SLB-1三轴系统,设计中砂在不同应力路径下的试验。通过室内试验,得到大孤山尾矿库中砂的应力-应变曲线,分析得出三种应力路径均体现出应变软化特性,应力路径对中砂的强度与变形有明显影响。在常规不排水三轴压缩试验中,对不同围压下的孔隙水压力随轴应变的变化先增加到峰值,随即下降。对于固结不排水三轴试验会产生负压。(4)计算了中砂在不同应力路径下的邓肯张模型的参数。(5)中砂在等主应力比路径下应力应变曲线符合幂函数形式。
[Abstract]:Rock and soil materials, such as sand and soil, are mainly composed of a large number of granular materials. The inhomogeneity of random distribution of grain shape, size and position is reflected in macroscopic mechanical properties such as compression, dilatancy and anisotropy.Although many scholars have done a lot of research on the mechanical properties of sand, there are few experimental studies on the mechanical properties of tailings under different stress paths.The main work carried out and its conclusions are discussed and analyzed at home and abroad on the research status of the mechanical properties of sand and tailings under different stress paths. The SLB-1 triaxial instrument is used in the test.The unconsolidated and unconsolidated undrained triaxial tests of sand in Dagushan tailings reservoir were carried out under different confining pressures, and the stress-strain curves and stress path curves were drawn according to the test data under different confining pressures.Under the same confining pressure, the strength of the consolidated sand is higher than that of the unconsolidated sand, that is, the consolidation degree has a significant effect on the strength of the medium sand.And the different confining pressure of the same stress path has an effect on the strength of sand.In the consolidation undrained stress path test, the pore water pressure under different confining pressures increases to the peak at first, then decreases and produces negative pressure. 3) using the SLB-1 triaxial system, the test of sand under different stress paths is designed.Through laboratory tests, the stress-strain curves of sand in Dagushan tailings reservoir are obtained. The results show that the three stress paths all reflect the strain-softening characteristics, and the stress paths have obvious influence on the strength and deformation of the sand.In the conventional undrained triaxial compression test, the pore water pressure under different confining pressures increases to the peak at first and then decreases with the axial strain.For consolidation undrained triaxial test, the negative pressure is generated. 4) the parameters of Duncan-Chang model of medium sand under different stress paths are calculated. 5) the stress-strain curve of medium sand under iso-principal stress ratio paths is in accordance with the power function form.
【学位授予单位】：辽宁科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU441

【参考文献】