A STUDY ON INFLUENCE OF PHYSICAL AND MECHANICAL PROPERTIES ON CHANGE OF SEDIMENTARY STRUCTURE IN SAND LAYER CAUSED BY LIQUEFACTION

液化引起的砂层沉积结构变化的物理力学性质影响研究

• 批准号: 07309016
• 负责人: TOHNO Ikuo
• 金额: $ 4.74万
• 依托单位: NATIONAL INSTITUTE FOR ENVIRONMENTAL SUTDIES
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07309016/
• 关键词: LIQUEFACTION; SAND LAYER; SEDIMENTARY STRUCTURE; MECHANICDAL PROPERTY; TOPOGRAPHICAL ANALYSIS; TEXTURE; DENSITY; TEST PIT; 粒度組成; 土質試験

Change in sedimentary structure and/or disturbance caused by liquefaction was investigated in the test pits of liquefied sand or gravel layrs, occured during the 1993 Hokkaido-Nansei-Oki (Southwest off Hokkaido) earthquake and 1995 Hyogo-Ken-Nanbu (South Hyogo prefecture) earthquake.(1) Liquefied sand dikes caused by Hokkaido-Nansei-Oki earthquake found in sandy silt layr of 1.5-2.0 m in thickness, were intruded from the underlying sand and gravel layr, including about 50% gravel-fraction.Lower part of the sand dikes is composed mainly of gravel, and flat ones tend to be turned nearly vertically. In the mid part of sand dikes, the amount of gravel decreasing, and in the upper part sand-sized fraction dominated. The liquefied layr is fluvial sand and gravel in the latest Holocene.(2) The liquefaction site distribution map was drew up after the Hyogo-Ken-Nanbu earthquake from Osaka bay area to Awaji Island and Naruto city.In the reclaimed land, liquefied layrs are the filled materials of weathered granite soil in Kobe. Matrix part among coarse granite blocks in the liquefied layr might be liquefied during the earthquake. Grain-size of liquefied materials in the sand dikes changes from coarse-grained and not well-sorted in the lower part, and fine-grained and well-sorted in the upper.(3) Result of cyclic triaxial compression tests, the change of strength ratio with excess pore water pressure during the cyclic loading was caused very little by the difference of initial structure of specimens taken from sand sample, but the volume change after liquefaction had influence on their specimens.

在1993年北海道西南部北海道地震和1995年兵库县南部地震中，对液化砂或砾石层的试验坑进行了液化引起的沉积结构变化和/或扰动的研究。(1)在厚1.5-2.0 m的桑迪粉土层中发现了由北海道南西冲地震引起的液化砂堤，液化砂堤是由下伏砂卵石层侵入的，含砾石约50%，砂堤下部以砾石为主，平坦砂堤有近垂直翻转的趋势。砂堤中部砾石含量减少，上部砂粒级占主导地位。液化层为全新世晚期的河流砂和砾石。(2)兵库县南部地震后，绘制了从大坂湾地区到淡路岛和鸣门市的液化场地分布图，在填海造地中，液化层是科比的风化花岗岩土的填充物。液化层中粗粒花岗岩块体间的基质部分在地震时可能发生液化。砂堤中液化物的粒度由下部的粗粒、分选不良向上部的细粒、分选良好转变。(3)动三轴试验结果表明，在动荷载作用下，砂土试样的初始结构差异对强度比随超静孔隙水压力的变化影响不大，但液化后体积的变化对其有一定的影响。

项目成果

I.Tohno, K.Endo, S.Mori, M.Suzuki et al.: "Formation of sand dike and its sedimentary structure coused by liquefaction-Trench excavating investigation in Kobe-" Proceedings of Japan national conference on National disaster science. No.15. 25-26 (1997)

I.Tohno、K.Endo、S.Mori、M.Suzuki 等：“液化引起的沙堤及其沉积结构的形成-神户沟渠挖掘调查——”日本国家灾害科学会议论文集。

沼田・森・陶野・遠藤・染谷: "まさ土埋立地盤の液状化地点におけるトレンチ調査" 阪神・淡路大震災に関する学術講演会論文集. 2. 99-106 (1997)

Numata、Mori、Sueno、Endo 和 Someya：“马萨多填海区液化点的沟槽调查”阪神淡路大地震学术会议论文集 2. 99-106 (1997)。

陶野・遠藤・森・鈴木 他: "液状化による砂脈の形式とその堆積構造-神戸市における開削調査-" 日本自然災害学会学術講演会要旨集. 15. 25-26 (1996)

Sueno，Endo，Mori，Suzuki，等：“液化引起的沙脉的形态及其沉积结构-神户市的发掘调查”日本自然灾害学会学术会议摘要15. 25-26（ 1996）

N.Someya, A.Numata, S.Mori, I.Tohno and H.Nakamura: "Observation of sand dykes in trench and examination of grain size distribution at liquefied sites near the Shiribeshi-toshibetsu river" Proceedings of Japan national conference on Geotechnical engineeri

N.Someya、A.Numata、S.Mori、I.Tohno 和 H.Nakamura：“在 Shiribeshi-toshibetsu 河附近的液化地点观察沙堤并检查粒度分布”日本全国岩土工程会议论文集

陶野・遠藤・鈴木・保坂 他: "1993年北海道南西沖地震による河成礫層の液状化" 日本自然災害学会学術講演会要旨集. 16. 27-28 (1997)

Sueno、Endo、Suzuki、Hosaka 等：“1993 年北海道 Nansei-oki 地震导致的河流砾石层液化”日本自然灾害学会学术会议摘要 16. 27-28 (1997)。