破砕帯地すべりにおける地すべり横断移動形状 (水平動, 上下動) の測定結果について : 試作したセン断変位計64台の設置結果より

Abstract

破砕帯地すべりに対して, 新らしく設計, 製作したセン断変位計を用いて計測機による地すべり横断移動形状測定を行い, どこからどこまでが動いているかわからないと言われるほど複雑な動きをする破砕帯地すべりの移動形態について大略次の事実を知ることができた。(1) 破砕帯地すべりにおいてその移動状況が地形的にわかりにくいのは, 主として地すべり移動自体が一定のパターンを持っていず, 多種多様の動きをするためであること。(2) 上下動が水平動を上回る規模で生じており, その変化形は地下谷形状に強く影響されていること。(3) 上下動, 水平動とも雨の少ない平常時にもかなり大きく動いており, その主たる原因は絶え間なく続く地下侵食の影響が考えられること。(4) 地表面形状の凸地が沈下し, 凹地が相対的に上昇する場合がかなり見られること。

Landslides in the crushed zone showed such complicated movements that the actual state of the landslide movements has not been grasped up to this point. The authors of this paper have tried to analyze the state of the movements on a line crossing landslide by designing, producing and setting up shear-deformation meters which measure three factors concerning the relative movement between two points. The following are the results which were obtained: (1) The reason that the state of the movements in the crushed zone-landslide are not easily understood from the configuration of the ground is mainly because the landslide movement has no constant pattern, but various types and scales. (2) The vertical movement is bigger than horizontal one, and both movements are greatly influenced by the shape of underground valley. (3) Considerable vertical and horizontal movement was observed during the period of no or little precipitation. The main cause is considered to be the unceasing underground erosion. (4) The interesting tendency was observed that the convexities of the ground subsided, while the concavities upheaved relatively.