Study on Propergation Characteristics of Crack and Weathering Depending on Inherent Structure of Rock

研究岩石风化作用的机理和了解岩石风化作用的程度具有重要意义。为了弄清干湿反复作用后岩石的力学性能、软化性能和内在结构之间的关系，进行了软化耐久性试验等室内试验。结果表明，随着干湿条件的反复，岩石的固有空隙和裂缝增加；认为在重复作用下，由于膨胀的孔洞或/和裂纹表现为一个弱面，使得材料的力学性能和松弛耐久性指数降低。在老化耐久性试验中，许多研究都是关于干燥温度、含水率和循环次数对老化现象的影响。也就是说，我们讨论了由粒度累积曲线得到的参数与滑坡耐久性试验后破碎产物的关系。参数包括粒径积累曲线中50%有效直径的偏差、2mm筛下产品的重量比、均匀性系数、剩余比差绝对值之和、比表面积。结果表明，在不受干燥温度影响的情况下，随着含水率偏差增大，软化现象增多，比表面积偏差等参数可以定量地确定为软化现象。断裂韧性是用裂纹扩展特性的大小来表示的，人们已经开发了许多方法来确定断裂韧性。断裂韧性试验要求试样具有精确规定的形状。然而，在某些情况下，用脆弱的岩石或可能风化的岩石制备所需的样品通常是困难的或实际上是不可能的。从这个角度出发，我们讨论了岩石的抗拉或抗压强度、岩石的冲击硬度数（RIHN）和岩石的石英含量等指标来预测断裂韧性。结果表明，断裂韧性与岩石的RIHN和石英含量具有较好的相关性。这表明裂纹的扩展过程取决于岩石的破碎性和固有结构。此外，还尝试了声发射技术在裂纹扩展特性估计中的应用。结果表明，利用声发射技术可以预测裂纹的扩展特性和老化耐久性试验的扩展过程。少

It is great importance to understand of the mechanism and to know of the extent of the weathring of rocks. In order to clarify the relationship between the mechanical properties, the slaking properties, and the inherent structure of rocks after the repetition of dry and wet condition, the laboratory tests such as the slaking durability test and so on were carried out. The results show that the inherent voids or/and cracks of the rocks were increased as the repetition of dry and wet condition. It is considered that lower mechanical properties and the slaking durability index were obtained under the repetition, because grown-up voids or/and cracks behave like a weakness plane. Much of the research in the slaking durability test is concerned with the effect of the dry temperature, the moisture content, and the number of cycle on the slaking phenomenon. Namely, we discussed the dependence of the parameters which were obtained by the grain size accumulation curve on the fragmentation produc … More ts after the slaking durability test. The parameters consisted of the deviation of the 50 % effective diameter in the grain size accumulation curve, the weight ratio of the products under the 2mm sieve, the uniformity coefficient, the summation of absolute value of the residual ratio difference, and the specific surface area. The results of the slaking durability test would be presented that the slaking phenomenon is increased with high deviation of the moisture content without the effect of the dry temperature Moreover, the parameter such as the deviation of the specific surface area can be determined as the slaking phenomenon in quantity.A number of approaches have been developed to determine the fracture toughness which is expressed as the magnitude of the propagation characteristics of cracks. The fracture toughness test requires the specimen to be in the precisely prescribed shape. However, it is often difficult or practically impossible in some cases, to prepare the specimen as required, with weak rocks or potentially weathering rocks. From this point of view, we discussed the index such as the tensile or the compressive strength of rocks, the rock impact hardness number (RIHN) , and the quartz content of rocks for prediction of the fracture toughness. The results show that the fracture toughness has a generally good correlation with the RIHN and the quartz content of rocks. It indecates that the propagation process of cracks depends on the fragmentation property and the inherent structure of rocks. Moreover, AE technique was tried to explore the possibility of its application in the estimation of the propagation characteristics of cracks. It is shown that the propagation characteristics of cracks and the propagation process during the slaking durability test can be predicted by using AE technique. Less