PRESUMPTION OF 3-D SHAPE OF SLIDE SURFACE BY ANALYSIS OF GROUND DISPLACEMENT DATA OBTAINED BY SURVEYING IN LANDSLIDING AREA

Abstract

Based on the assumption that the deformation of a landsliding mass is small enough compared with the displacement of the mass, many analytic procedures to presume the shape of underground slide surface have been proposed. Several parts of the old procedures are improved in this paper. First, to presume the complicated slide surface, combination of polynomial functions representing partial slide is examined. Next, to raise the accuracy of presumption, the concept of data weight is introduced into the least square method. Effect of these improvements is verified by numerical analysis applied to actual landslide area, Narao district, Nagano prefecture in Japan.