曾文溪日新護岸堤體土壤抗液化強度之研究

Investigating the soil liquefaction resistance of the soils for the Ri Shin Embankment at Tseng Wen River

吳柏翰(Wu, Bo-Han) ； 吳建宏(Wu, Jian-Hong) ； 古志生(Ku, Chih-Sheng)

《中華防災學刊》 10卷2期 (2018/09) Pp. 165-172

摘要

日新護岸在美濃地震時發生土壤液化破壞，雖然並未造成人員重大傷亡，但該事件提醒工程師未來在河堤建造、設計過程中，事先瞭解地下水位的分布及堤體土壤動態行為特性的重要性。試驗以高灘地重模土壤為對照組，該土壤屬於容易液化的粒徑分布。當篩除日新護岸細粒料至5%以下為乾淨砂時，抗液化強度上升了約91%。當日新護岸土壤相對密度設定為33%、50%、70%時，日新護岸土壤之抗液化強度與相對密度的增加成正關係，這兩種方式皆明顯增加日新護岸土壤抗液化能力。而添加泥岩添加物之取代量分別為10%與30%，雖然細粒料含量增加，當泥岩取代量10%時，液化阻抗卻下降了約10%；當泥岩取代量30%時，液化阻抗上升了約6%左右，可知以泥岩添加料取代土壤雖然提高細粒料含量，但細粒料內多含粉砂，對提升日新護岸土壤抗液化能力的效果不彰。

關鍵字

曾文溪堤防 ； 粒徑分布 ； 動態三軸試驗 ； 粉土質砂

並列摘要

Soil liquefactions occurred at the Rishin revetment during the Meinong Earthquake. The event reminds the engineers clarify groundwater table, soil liquefaction resistance and the dynamic behaviour of the soils for the design and construction in the future. In this study, we take the soil of the Rishin Embankment as control group. The local soil is within the liquefaction grain size distribution. The liquefaction resistance of clean sand, which screening the fine content less than 5%, increases approximately 91%. The soil liquefaction resistance increases as the increasing relative density of the soil of the embankment from 33%, 50%, to 70%. Therefore, both methods notably increase the liquefaction resistance of the Rishin Embankment soil. In contrast, adding mudstone powder is ineffective in increasing the liquefaction resistance of the soil although the fine content may increase because most of the fine contents are classified to be silt. Compare tolocal soils, when the mudstone content increases to 10%, the liquefaction resistance drops roughly 10%, whereas it increases around 6% when the mudstone content is increased to 30%.

並列關鍵字

Tsengwen River bank ； grain size distribution ； dynamic triaxial test ； silty sand