Research of the estimate of the slope failure of rainfall in the damaged ground by the Tokachi and Hyogoken-Nanbu Earthquakes by using ground penetrating radar and field emission type electron microscope

1995年兵库县南部和德知县发生的地震对这片丘陵地带造成了严重破坏。在丘陵地带的边缘观察到了严重的破坏土地。造成这种现代建筑严重破坏的原因是软土地基和垃圾填埋场。应用探地雷达(GPR)方法对地震中的滑坡进行了探测。使用100 MHz天线的SIR-3000(GSSI)对沿受损区域的许多探地雷达线进行了检查。在探地雷达剖面和张性裂隙地表上均发现了地下滑坡构造。构造在探地雷达剖面上的倾角不是平缓的。弱反射图像显示了含水的软基。这张微弱的影像位于滑坡地区。因此，探地雷达方法是分析地表破损的有效方法。这些陡峭的斜坡是由深风化的花岗岩组成的。用X射线衍射法对陡坡中的蚀变矿物进行了鉴定，以确定风化产物。利用EDXRF对深部边坡中的许多岩石进行了化学成分分析，以检验其风化程度。在崩塌的陡峭山坡上，易淋易淋是显而易见的。淋溶倾向与风化程度相吻合。通过化学成分检测，有可能定量地反映出陡坡的风化过程。X-射线衍射仪显示，许多滑坡已经风化了高岭石等矿物。从这些结果来看，它似乎是由暴雨引起的坍塌

The 1995 Hyogo-ken Nanbu and Tokachi Earthquakes had caused serious damages on the hilly land. Serious damaged grounds were observed on the margin of the hilly lands. The reason for this serious damaged modern buildings is soft ground and landfill area. We applied the ground penetrating radar (GPR) method for the landslide in the earthquake. Many ground penetrating radar lines along the damaged area were examined by using the SIR-3000 (GSSI) with 100MHz antenna. The landslide structures under the ground were found on the GPR profiles as well as ground surface of the tension cracks. The dip of the structures on the GPR profiles is not gentle angle. The weakly reflected images show the water-bearing soft ground. This weakly image is located in the landslide area. Thus, ground penetrating radar method is useful for the damaged ground analyses.The steep slopes are widely distributed in Mount Rokko. These steep slopes were composed of deep weathered granitic rocks. Altered minerals in the steep slopes were identified by X-ray diffraction to estimate of weathering products. Chemical composition of the many rocks in the deep slopes was also analyzed by using EDXRF to check the grade of weathering. In the collapre steep slopes, readily leachable is clear. The leaching tendency coincides with the grade of the weathering. It is possible that the examination by the chemical composition quantitatively shows the progresses of the weathering of the steep slopes. Many slope failures have weathered minerals such as kaolinite by using X-ray diffraction. From these results, it seems to generate a collapse by the heavy rainfa