砂粒径对相似材料力学特性的影响机理
投稿时间:2019-04-01  修订日期:2020-01-10  点此下载全文
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作者单位E-mail
齐琦 新疆大学地质与矿业工程学院 825443823@qq.com 
管伟明 新疆大学地质与矿业工程学院 4560889@qq.com 
温颖远 新疆大学地质与矿业工程学院  
基金项目:国家自然科学基金资助项目(编号:51764050);2019年新疆维吾尔自治区研究生创新项目(编号:XJ2019G058);国家级大学生创新训练项目(编号:201910755048)
中文摘要:为探明砂粒径对相似材料力学特性的影响机理,提高相似物理模拟实验的精度,对0.1mm—3mm的11种粒径条件下的99个力学试件进行了单轴抗压测试及渗透系数测试,并从石膏水化反应机理和内外部结构特征两个方面阐释了试件力学特性变化的规律及机理。研究发现:砂粒径对相似材料的抗压强度影响范围在-16.51%—49.79%之间,但总体上粒径对材料强度的影响成负相关关系;SEM电镜观察发现,在较小砂粒径条件下生成的CaSO4·2H2O晶体多以相互交织的针状和短粗棒状晶体呈现,材料强度也较大,而粒径大时多以层片状、板状出现,交织程度差,力学强度弱;表征观察发现,砂粒径越小的试件界面缝长度与宽度则越小,砂粒的比表面积越大,接触应力更加均匀,不易产生应力集中而破坏材料;相似材料的渗透系数随着砂粒径的增加而增大;当粒径大小在1.5mm—2.0mm时,试件的单轴抗压强度与目标值最为接近。
中文关键词:砂粒径  相似材料  石膏结晶  抗压强度  水化反应
 
Influence mechanism of sand particle size on mechanical properties of similar materials
Abstract:In order to find out the influence mechanism of sand particle size on the mechanical properties of similar materials and improve the accuracy of similar physical simulation experiments, 99 mechanical specimens under 11 particle size conditions of 0.1mm—3mm were tested for uniaxial compression and permeability coefficient. The law and mechanism of the mechanical properties of the specimens were explained from two aspects: gypsum hydration reaction mechanism and internal and external structural characteristics. The study found that the influence of sand particle size on the compressive strength of similar materials ranged from -16.51% to 49.79%, but the overall particle size had a negative correlation with the material strength; SEM electron microscopy found that in smaller sand grains The CaSO4·2H2O crystals formed under the diameter condition are mostly intertwined needle-like and short-thick rod-like crystals, and the material strength is also large. When the particle size is large, it is mostly in the form of a sheet or a plate, and the degree of interlacing is poor, and the mechanical strength is weak; characteristic observation shows that the smaller the sand particle size is, the smaller the length and width of the interface joint is, the larger the specific surface area of the sand is, the more uniform the contact stress is, and thus the less stress concentration to destroy the material; The permeability coefficient of similar materials increases with the increase of sand particle size; when the particle size is between 1.5mm and 2.0mm, the uniaxial compressive strength of the test piece is closest to the target value.
keywords:Sand particle size  similar materials  gypsum crystal  compressive strength  hydration reaction
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