Heavy rainfall frequently occurred in Kyushu and triggers the landslides every year. This study observes the landslides which occurred in Oita Prefecture, Kyushu, Japan. The landslides in this study, consisting of the same soil materials, tuff breccia and andesite materials; however, the landslide mechanisms were different. Two landslides occurred caused by heavy rainfall in the different timing of the landslide occurrence, and another landslide occurred without the heavy rainfall or an earthquake occurs. Therefore, this study aims to analyse the physical and mechanical properties of tuff breccia and andesite materials with diverse landslide mechanisms. This study performed soil stratigraphic analysis and soil hardness measurements in the field, and performed physical properties, saturated permeability, mechanical properties, and XRD tests in the laboratory. This study found that characteristics of tuff breccia and andesite in diverse mechanisms of landslides were not very different, especially on the landslides caused by heavy rainfall. Furthermore, the landslide in the andesite and tuff breccia areas could be divided into three types based on the timing of the landslide occurrence, scale of the landslide, and landslide mechanisms.

中文翻译：

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日本九州大分县不同滑坡机理中凝灰岩角砾岩-安山岩的特征

九州经常发生强降雨，每年都引发滑坡。本研究观察了日本九州大分县发生的滑坡。本研究中的滑坡由相同的土壤材料，凝灰岩角砾岩和安山岩材料组成；但是，滑坡机制不同。在不同的滑坡发生时间，两次降雨是由强降雨引起的，另一次滑坡是在没有强降雨或地震的情况下发生的。因此，本研究旨在分析凝灰岩角砾岩和安山岩材料具有各种滑坡机理的物理和机械性能。该研究在现场进行了土壤地层分析和土壤硬度测量，并进行了物理性能，饱和渗透率，机械性能，和XRD测试在实验室中进行。研究发现凝灰岩角砾岩和安山岩在各种滑坡机制中的特征差异不大，特别是在暴雨造成的滑坡上。此外，根据滑坡发生的时间，滑坡的规模和滑坡机理，安山岩和凝灰岩角砾岩地区的滑坡可分为三种类型。