学会誌「自然災害科学」

自然災害科学56 Vol.19,No.4, 2001

【論文】[Regular Paper]

液状化による流動変位予測のための地盤の硬軟分布評価に関する研究

Evaluation of Spatial Hardness of Soil Layers to Estimate Liquefied Ground Flow

吉田 雅穂*・宮島　昌克**・北浦 勝**

Masaho YOSHIDA*, Masakatsu MIYAJIMA** and Masaru KITAURA**

Abstract

Horizontal ground displacements caused by liquefied ground flow were observed at reclaimed lands during the 1995 Hyogoken-Nambu earthquake. Many displacements were not due to the influence of the inclination of ground surface and movement of quay wall. The present paper aims to find the causes of the displacements mentioned above and to investigate how to estimate their directions and magnitudes. A method is proposed here to evaluate the spatial distribution of SPT N-value. Although this method is usually used to investigate a trend surface on altitude, it was applied to evaluation of the spatial hardness of soil layers. The gradient and azimuth of trend surface on SPT N-value were found using data of reclaimed lands in Kobe area. The boundary of geological stratum that was decided by the distribution of SPT N-value was easily estimated using the proposed method. Furthermore, it was clarified that the direction of horizontal displacement of ground surface was influenced by the inclination of boundary between soft and hard soil layers. It will be expected that this method is useful to estimate the liquefied ground at the level reclaimed land.

キーワード:

地震，液状化，地盤流動，N値，硬軟分布評価，1995年兵庫県南部地震

Key words:

evaluation of hardness of soil layers, the 1995 Hyogoken-Nambu earthquake
*
福井工業高等専門学校環境都市工学科
Dept. of Civil Engineering, Fukui National College of Technology
**
金沢大学工学部土木建設工学科
Dept. of Civil Engineering, Faculty of Engineering, Kanazawa University