地すべり
Online ISSN : 1884-3956
Print ISSN : 0285-2926
ISSN-L : 0285-2926
28 巻, 2 号
選択された号の論文の6件中1~6を表示しています
  • 林 拙郎, 山森 幹
    1991 年 28 巻 2 号 p. 1-8
    発行日: 1991/09/25
    公開日: 2010/03/16
    ジャーナル フリー
    以前筆者等が示した第3次クリープの経時過程に関する基本式を用いて崩壊予測を行った。まず, 基本式より崩壊時間trを求める式を導いた。その式は, exp (at) に関して形式上, 斎藤式と同様である。したがって, 係数aの値を数値的に仮定すれば, 斎藤の図式解法と同様に一定移動量Δlを3箇所設定した予測法が可能となる。この予測法をa-tr法と名付け, 崩壊予測を行った。その結果は, 斎藤の図式解法に比してときには悪い場合もあるが, ほぼ同程度である。
  • Ippei KITAHARA, Hiroyuki YOSHIMATSU, Kazunori FUJISAWA
    1991 年 28 巻 2 号 p. 9-19
    発行日: 1991/09/25
    公開日: 2010/03/16
    ジャーナル フリー
    The behavior of sediment accompanying the collapse of mountainsides was examined as part of a study of the mass flow of sediment and water, which is represented by debris flow. In connection with the behaviour of collapsing sediment, the following equation expresses the applicable resistance law in the case of dry sand.
    τ=τyg
    where, τy: Yield stress, τg: Force resulting from the non-elastic collision between grains.
    The authors derived the equations for the velocity distribution in the vertical direction and the mean velocity of the mass flow of dry sand from the resistance law mentioned above by making use of Bagnold's grain arrangement model. The velocity distribution thus obtained was evaluated through flow tests of dry sand. Moreover, a numerical simulation model of the flow and sedimentation of collapsing sediment was created by making use of the resistance law mentioned above. This simulation model was compared with flow and deposition tests of dry sand carried out in two-dimensional waterways with the object of verifying its appropriateness.
  • 矢田部 龍一, 八木 則男, 榎 明潔
    1991 年 28 巻 2 号 p. 20-26
    発行日: 1991/09/25
    公開日: 2010/03/16
    ジャーナル フリー
    地すべりのすべり層の粘性土のせん断試験が行われることが多くなっている。しかし, 中には排水条件を混同したような取り扱いもみられる。そこで, すべり層の粘性土の強度定数に関して有効応力の立場から検討を行った。そして, 有効応力で考えれば粘性土の強度定数は一義的に定められることを明らかにし, また, 従来の研究の中にみられる問題点を指摘した。
  • 中森 克己, 楊 普才
    1991 年 28 巻 2 号 p. 27-32
    発行日: 1991/09/25
    公開日: 2010/03/16
    ジャーナル フリー
    The residual strength of clay is taken into consideration in the stability analysis of landslids, but the present technology is in such a state that the method of measuring residual strength is not established as yet. The residual strength varies with the type of measuring apparatus used such as ring shear apparatus or reversal direct shear apparatus and also it varies with clay sample condition such as disturbed or undisturbed. The present research is focussed on the condition of clay sample and its relation with residual strength. As a common practice the residual strength of clay is measured with the sample in disturbed condition and with the basic conception that it is not influenced by the stress history. In this research residual strengths of the same clay in both disturbed and undisturbed conditions are measured and obviously the results are different. Thus it is to be suggested that the residual strength should be measured with the clay sample in undisturbed condition.
  • 水野 恵司
    1991 年 28 巻 2 号 p. 33-39
    発行日: 1991/09/25
    公開日: 2010/03/16
    ジャーナル フリー
    This paper describes slope forms and landslide activities in the area underlain by Tertiary mudstone of the Teradomari and Shiiya Formations of Niigata Prefecture, Frequency distribution of angle for randomly sampled slopes in the area showed that the angle of 15 degrees was defined as a criterion for classifying of these slopes. Two types of landslide have been identified in the area: (1) Rapid-type landslides, characterized by their higher speed and larger morphological change, occur in the weathered zone of the mudstone, and (2) Slow-type landslides having a characteristics of their slower speed and smaller morphological change occur in the colluvial deposits derived from previous landslides. The investigation for a large number of slope profiles of these landslides indicated that the rapid-type landslides originally arised on a steeper slope segment than 15 degrees and the slow-type landslides were restricted to a gentler slope segment than 15 degrees.
  • その2, 新旧地すべり面と応力解析
    早川 嘉一, 高浜 信行, 片桐 信二, 福本 安正
    1991 年 28 巻 2 号 p. 40-47
    発行日: 1991/09/25
    公開日: 2010/03/16
    ジャーナル フリー
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