Study on Long-term Stability of Rock

岩石在各种复杂的自然条件下都会受到破坏，了解自然环境因素的综合作用对于评价岩石的稳定性是必不可少的。然而，与岩石稳定性相关的各种因素的影响还没有得到很好的解决。尤其是循环加载和循环加热的实验结果，尽管其重要性很大，但也是有限的。本文研究了考虑低温循环加热影响的岩石耐久性及其评价方法。本报告由三部分组成：一是利用弹性波速估计岩石的稳定性；二是利用冻融试验估算岩石的耐久性；三是将可视化信息技术应用于岩石裂隙结构的分析。在第一部分中，建议将弹性波速的测量作为岩石长期稳定性的无损检测。然后，将其应用于由阿马库萨砂岩组成的本岛江户末期大桥的稳定性诊断。在第二部分中，采用圆柱形试件进行了冻害试验，作为岩石耐久性的评价方法。揭示了低温循环加热条件下阿马库萨砂岩风化过程的总体趋势。通过对比第一部分和第二部分的试验结果，阐明了冻害试验用于岩石耐久性评价的可行性。第三部分将可视化信息技术应用于岩石裂隙结构的分析。

Rocks are damaged under various and complex natural condition, Understanding of the composite action of natural environmental factors is indispensable for estimating the stability of rock. However, there are unsolved problems for the effect of each factor associated with the stability of rock. Especially, experimental results of the cyclic loading and cyclic heating are limited in spite of their importance. We studied on the durability of rock and its estimation method, considering the effect of the cyclic heating under low temperature.This report consists of three parts as follows :I. Estimation of stability by elastic wave velocity.II. Estimation of durability of rock under frost action test.III. Application of visual information technique to analysis on structure of crack in rock.In the part I, measurement of the elastic wave velocity is suggested as the non-destructive test, by which the long-term stability of rock can be estimated. Then, it is applied to the stability diagnosis of Gion bridge, Which was constructed at the end of Edo period in Hondo city, consisting of Amakusa sandstone. In the part II, the frost action test is carried out as the estimation method of durability of rock, using cylindrical specimen. It is shown the general trend of weathering process of Amakusa sandstone by cyclic heating under low temperature. Then it is clarified that the frost action test is available for the estimation of durability of rock, comparing experimental results in the part I and II. Furthermore, in the part III, visual information technology is applied to the analysis on the structure of crack in a rock.