Improvements on Three Dimensional Tracking Method for Presumption of Underground Slide Surface

Abstract

Some improvements on analytic procedure of “three dimensional tracking method” used for presumption of underground-slide-surface-geometry in landslide area is discussed. Compared with the previous procedure (cf. J. of JLS, Vol.26, No.3, 1989), main improvements are summarized as follows:1)to debug the singular matrix appeared in normal equation derived by least-square-method, 2) to process arbitrary number of boundary-point-data mathematically, and3) to consider positional error of the boundary-point-data and tracking-point-data.By these improvements, the procedure became simple and rational, thus the presumption reliable. Through computer simulation, precision of the presumption affected by selection of the boundary-points and tracking-points is studied. At the same time, influence of the positional error is examined.Application of the improved procedure to actual landslide in Komoro district is demonstrated.