A study on the establishment of landslide early warning system against torrential rainfall in Indochina region

在这项研究中，现场监测的重点是水的质量平衡，由于暴雨的斜坡，包括风化花岗岩，这是占主导地位的滑坡倾向的地质条件在中南半岛半岛，已进行。结果表明，降雨在坡面附近的非饱和土中通过墨水瓶效应产生径流、入渗和滞留。将计算的入渗量作为给定的边界条件，考虑地表滞留的影响，进行非饱和-饱和渗流有限元分析，结果与实测值吻合较好。此外，对于浅层滑坡的机理，指出在不产生地下水位的情况下，饱和度的增加导致有效粘聚力的降低可能是边坡失稳的触发因素。

In this study, field monitoring focusing on water mass balance due to torrential rainfall in the slope comprising weathered granite, which is dominate landslide-prone geological condition in Indochina Peninsula, has been conducted. The results showed that precipitation is divided into runoff, infiltration into subsoil and surface retention, which is generated by ink-bottle effect in unsaturated soil near slope surface. And, the results of FEM unsaturated-saturated seepage analysis, in which calculated infiltration into subsoil is treated as prescribed boundary condition considering the effect of surface retention, showed good agreement with that of measurement. In addition, as for mechanism of shallow landslide, it is pointed that the decrease of effective cohesion due to increase of degree of saturation may be the trigger of slope failure without generation of groundwater table.