Strength,fragmentation and fractal properties of mixed flaws

Experiments on Portland cement samples containing mixed flaws are conducted to investigate the strength, fragmentation and fractal properties. Flaw geometry is a new combination of two edge-notched flaws and an imbedded flaw, which is different from those in the previous studies, where parallel or coplanar flaws are used. The physical implications of the shear-box test applied to result to rock slopes are studied. The physical and analytical fragmentation characteristics of preflawed samples are analyzed through the sieve test and fractal theory, respectively. Three different patterns of tensile cracks and shear cracks are observed. A sliding crack model is presented to elucidate the brittle failure flaws. In all of the cases of the shear-box tests, the coalescence is produced by the linkage of shear cracks, and two types of coalescence (Type C1 and Type C2) have been classified, which tend to confirm the observations from the numerical model and field of jointed rock slopes. The shear strength is a function of the flaw geometry and the shear–normal stress ratio. The result of sieve tests indicates that the fragment size distribution of fragments has the fractal property, providing a physical understanding of the fragmentation mechanism. The fragments under the shear-box test have fractal dimensions between 2.2 and 2.6, which are larger than those under the compression test but similar to those in the fault cores. The fragmentation in the case of Type C2 has a smaller fractal dimension, corresponding to a larger shear strength.     

高岭石-多水高岭石演化系列的红外吸收光谱研究

本文用红外吸收光谱对我国所产高岭石-多水高岭石演化系列的四种不同类型的矿物及其热处理产物进行了初步研究,分析了各类矿物的吸收特征,探讨了它们之间的变化关系和脱水过程在红外光谱上的反映。 实验使用KBr压片法制备样品,在Perkin-Elmer 577型红外分光光度计记录红外光谱图。文中所用样品有江苏苏州与河北宣化的结晶完好的高岭石,广东清远清草岭与湖南谭家山的耐火粘土石,福建德化与湖南四青水库的多水高岭石以及四川叙永大树区与山西阳泉的水合多水高岭石。     

湖北均县风化型高岭土中蒙脱石矿物的形成和变化

湖北均县风化淋滤型高岭土矿床赋存在与一定风化母岩岩性相依存的同一时代层位中。矿体产于寒武纪下统（∈₁）和震旦系上统灯影组（Zbdn）之间的平行不整合面上,呈断断续续的含矿带。风化母岩为寒武系下统暗色含硫有机质、硅质页岩,含矿带的下盘岩性为灰白色厚层状白云岩。