Joint research on the wave-induced liquefaction of sea bed

海床波浪液化联合研究

• 批准号: 04044121
• 负责人: NAGO Hiroshi
• 金额: $ 8.83万
• 依托单位: Okayama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04044121/
• 关键词: LIQUEFACTION; WATER WAVE; SEA-BED; GEO-ACOUSTICS; COASTAL EROSION; COASTAL STRUCTURE; 音響伝播

In this research project the wave-induced liquefaction of sea-bed is treated analytically and experimentally. The main results of this project are summerized below.1.There are two types of liquefaction in the loosely deposited sea-bed ; one is sustainable liquefaction which is accompanied by the built-up mean pore pressure and the other one is transcient liquefaction caused by the damping and phase lag in the oscillating pore water pressure. The sand bed is densified by such process of liquefaction.2.The dynamic similitude of this phenomenon was derived by using the one-dimensional mathematical model and the applicability of the model was verified numerically, thereby the basis for the experimental work was made clear.3.The entrained air in the sea-bed affect strongly the feature of the wave-induced liquefaction. To estimate the quantity of the involved air, we tried to adopt a measuring technique based on geo-acoustics. At present there are several problems in the method for the practical use.4.The flow of liquefied sand around several types of coastal structures are observed in the laboratory. The dynamic behavior of this phenomenon is explained to some extent by the mathematical model developed in this research.5.It has been shown through the field observation of a large scale coastal erosion occured in Yumigahama beach in Tottori Prefecture, the wave-induced liquefaction near the coast is an important factor to cause such a large scale erosion.

本文对波浪引起的海床液化问题进行了理论分析和实验研究。主要研究结果如下：1.松散沉积海床的液化可分为两种类型：一种是伴随着平均孔隙水压力上升的持续性液化，另一种是由振荡孔隙水压力的阻尼和相位滞后引起的瞬时性液化。利用一维数学模型推导了波浪液化的动力学相似关系，并对模型的适用性进行了数值验证，为试验研究奠定了基础; 3.海床中夹带的空气对波浪液化的特性影响很大。为了估计所涉及的空气量，我们尝试采用基于地质声学的测量技术。目前该方法在实际应用中还存在一些问题。4.对几种典型的海岸结构物进行了液化砂土绕流的实验室观测。5.对鸟取县由美滨海滩发生的大规模海岸侵蚀的现场观测表明，海岸附近的波浪液化是造成这种大规模侵蚀的重要因素。

项目成果

NAGO,H., S.MAENO: "SETTLEMENT OF CONCRETE BLOCK INTO SAND BED UNDER CYCLIC LOADING OF WATER PRESSURE" Proc.of 26th CONGRESS OF IAHR. (IN SUBMISSION).

NAGO,H., S.MAENO：“在水压循环荷载下将混凝土块沉降到砂床中”Proc.of 第 26 届 IAHR 大会。

名合宏之,前野詩朗,小谷裕司,西峯福宏: "変動水圧場における護岸裏込土砂の流出機構に関する研究" 土木学会 水工学論文集. 39. 721-726 (1995)

Hiroyuki Nago、Shiro Maeno、Yuji Kotani、Fukuhiro Nishimine：“波动水压场中回填土砂的流出机制研究”日本土木工程师学会，水利工程学报 39. 721-726 (1995)。

Hiroshi Nago,Shiro Maeno,Takayuki Matsumoto,Yasushi Hachiman: "Liquefaction and Densification of Loosely Deposited Sand Bed under Water Pressure Variation" Proc.of Third(1993)International Offshore and Polar Engineering Conference. 1. 578-584 (1993)

Hiroshi Nago，Shiro Maeno，Takayuki Matsumoto，Yasushi Hachiman：“水压变化下松散沉积砂床的液化和致密化”，第三届（1993）国际近海和极地工程会议论文集。

名合宏之,前野詩朗,清水雄一,山本哲雄: "変動水圧場におけるブロックの沈下防止に関する研究" 土木学会 海岸工学論文集. 41. 601-605 (1994)

Hiroyuki Nago、Shiro Maeno、Yuichi Shimizu、Tetsuo Yamamoto：“防止波动水压场中的块体沉降的研究”日本土木工程师学会，海岸工程学报 41. 601-605 (1994)。

NAGO,H., S.MAENO,Y.SHIMIZU,T.YAMAMOTO: "PROTECTION METHOD TO THE SETTLEMENT OF CONCRETE BLOCK UNDER WAVE MOTION" Proc.of COASTAL ENGINEERING,JSCE. 41. 601-605 (1994)

NAGO，H.，S.MAENO，Y.SHIMIZU，T.YAMAMOTO：“波浪运动下混凝土块沉降的保护方法”Proc.of Coastal Engineering，JSCE。