Long-distance flow mechanism of gentle slopes under seepage due to liquefaction-induced water film during 2018 Sulawesi earthquake, Indonesia

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations Pub Date : 2025-04-19 DOI:10.1016/j.sandf.2025.101611

T. Kokusho , T. Sawada , H. Hazarika , Y. Isobe

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引用次数: 0

Abstract

Unprecedented liquefaction-induced slope failure occurred during the 2018 Indonesian Sulawesi earthquake in which more than 2000 people were killed by sliding debris flows in very gentle slopes with a 2 % gradient. In order to clarify the mysterious mechanism of how long-distance debris flows could occur on such gentle slopes, transient seepage analyses were conducted focusing on the impact of a thin water film of a limited horizontal length which was supposed to emerge during liquefaction in a layered soil profile beneath a low-permeability cap layer of the slope influenced by stationary seepage. Consequently, the water film was found to play a key role in transmitting higher pressure head to the tip at a lower elevation with a marginal head loss, leading to the downslope extension of the water film and associated boiling failure in the cap layer. The water film that formed during liquefaction was significant in realizing the long-distance flows down the gentle slopes during and even after liquefaction as long as the water film was sustained. This mechanism should be newly recognized as a serious threat to a society due to liquefaction in gentle slopes during strong earthquakes.

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2018年印尼苏拉威西地震液化水膜作用下缓坡长距离渗流机制

2018年印度尼西亚苏拉威西岛地震发生了前所未有的液化引起的边坡破坏，2000多人死于坡度为2%的非常缓坡上的滑动泥石流。为了弄清这种缓坡上长距离泥石流发生的神秘机制，我们进行了瞬态渗流分析，重点研究了受固定渗流影响的边坡低渗透帽层下分层土壤剖面液化过程中出现的有限水平长度的薄水膜的影响。因此，水膜在将高压水头以较小的水头损失传递到较低高度的顶部方面发挥了关键作用，导致水膜的下坡延伸和相应的帽层沸腾失效。液化过程中形成的水膜对实现液化过程中和液化后沿缓坡的长距离流动具有重要意义，只要水膜持续存在。这种机制应该被重新认识到是对社会的严重威胁，因为在强震期间，缓坡会液化。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Soils and Foundations 工程技术-地球科学综合

CiteScore

6.40

自引率

8.10%

发文量

审稿时长

5 months

期刊介绍： Soils and Foundations is one of the leading journals in the field of soil mechanics and geotechnical engineering. It is the official journal of the Japanese Geotechnical Society (JGS)., The journal publishes a variety of original research paper, technical reports, technical notes, as well as the state-of-the-art reports upon invitation by the Editor, in the fields of soil and rock mechanics, geotechnical engineering, and environmental geotechnics. Since the publication of Volume 1, No.1 issue in June 1960, Soils and Foundations will celebrate the 60th anniversary in the year of 2020. Soils and Foundations welcomes theoretical as well as practical work associated with the aforementioned field(s). Case studies that describe the original and interdisciplinary work applicable to geotechnical engineering are particularly encouraged. Discussions to each of the published articles are also welcomed in order to provide an avenue in which opinions of peers may be fed back or exchanged. In providing latest expertise on a specific topic, one issue out of six per year on average was allocated to include selected papers from the International Symposia which were held in Japan as well as overseas.