細料含量與非均向壓密對岸邊土壤液化強度之影響

INFLUENCE OF FINE CONTENT AND ANISOTROPIC CONSOLIDATED CONDITION ON LIQUEFACTION RESISTANCE OF RIVERSIDE SANDS

本文目的在探討細料對岸邊砂土液化之影響，而側向解壓之非均向性壓密之影響亦在研究之列，本文使用前鎮河岸邊砂土與當地細料，分別控制混合料相對密度30%、50%和70%，細料含量0%、5%、15%和25%，進行均向壓密與非均向壓密狀態之動三軸試驗。均向壓密試驗結果顯示，除鬆砂及中等緊密砂細料含量5%之試體，砂土之液化強度將隨細料含量的增加而降低。非均向壓密試驗結果顯示，不含細料試體非均向壓密試體液化強度皆較均向壓密試體為大，故細料可能使試體承受反覆剪應力之能力下降。此結果顯示工程應用上，液化分析僅使用均向性數據將傾向危險。

The object of this paper is to investigate the effect of fines content on the liquefaction resistance of soil beside a river. The factor of the anisotropic condition for lateral unloading will also be studied. Accordingly, with riverside sands from near the Chen-Zerng river of Kaosiung city, mixed local fines were used to conduct a series of dynamic triaxial tests under isotropic and anisotropic conditions. The relative densities varied from 30% to 70% and the fines content were 0%, 5%, 15% and 25%. The test results indicate that the liquefaction resistance of specimens subject to isotropical condition will decrease with increasing fines content except for loose/medium dense specimens with FC=5%. Since the testing results of clean sands are higher than those of sands with fines content, the liquefaction resistance of specimens, apparently, will decrease due to adding fines to produce an isotropic condition. Thus the liquefaction potential evaluation is applicable for engineering; the isotropic condition revealed could tend to danger.