前期反復荷重對砂土液化阻抗與剪力波速之影響

The Influence of Previous Cyclic Loading on Liquefaction Resistance and Shear Wave Velocity of Sand

游步上(Pu-Shang You) ； 陳堯中(Yao-Chung Chen) ； 許家華(Chia-Hua Hsu) ； 吳松旺(Sung-Wang Wu)

《中國土木水利工程學刊》 21卷2期 (2009/06) Pp. 231-238

https://doi.org/10.6652/JoCICHE.200906_21(2).0010

摘要

本文以新店砂重模試體進行彎曲元件試驗與動力三軸試驗，探討於不同細粒料含量及不同相對密度等條件下，前期反復荷重對砂質土壤最大剪力波速與液化阻抗之影響。試驗結果顯示，隨前期反復荷重之增加，試體之液化阻抗亦會增大，但若超過某一臨界的前期反復荷重則其液化阻抗會開始降低，此臨界之門檻值隨不同細粒料含量而變動。此外，試體經前期反復荷重作用後其剪力波速並未有明顯之變化，主要係隨相對密度之不同而有所改變。另試驗結果亦顯示，試體之剪力波速與其液化阻抗成正比關係，即剪力波速越大其液化阻抗越高。

關鍵字

前期反復荷重 ； 應力歷史 ； 液化阻抗 ； 剪力波速

並列摘要

This research investigates the liquefaction resistance and the shear wave velocity of Hsin-Dian sand by using cyclic triaxial tests together with bender element tests. The effects of previous cyclic loading on the dynamic properties of sand were studied with different fines content and relative density. Test results show that liquefaction resistance would increase with increasing previous cyclic loading up to a critical value, and then it would start decreasing with further increase of previous cyclic loading. The critical value of previous cyclic loading would change with different fines content. In this research, the shear wave velocities of the samples presheared by cyclic loading did not change obviously. The shear wave velocity is influenced mostly by relative density. Test results also show that liquefaction resistance increases with increasing shear wave velocity.

並列關鍵字

previous cyclic loading ； stress history ； liquefaction resistance ； shear wave velocity