Approach to the Strength Behaviors and Microstructural Changes of Loess under Dynamic Load

Abstract

With the help of the dynamic consolidation instrument, the shear strength characteristics of loess have been studied. The experiment results revealed that the shear strength varies in stages with increasing number of blow counts (N). During the initial stage, a uniform increase in soil strength is obtained. Upon reaching a limit, the shear strength decreases. A microstructural analysis demonstrates that this variation of shear strength is basically controlled by the alteration of microstructure state in terms of the growing heterogeneity of size and orientation of grains as well as increase in structural damage.

本文通過室內模擬強夯試驗研究了黃土在動力荷載的作用下其強度變化規律 ,發現強度隨夯擊次數的增加將出現階段性變化。初期以單調的遞增變化為特征 ,但達到某一界限值后出現了宏、微觀變化差異。前者以增幅減緩為主 ,而后者則出現了強度逐漸降低現象。結構分析表明 ,強度的這種變化主要受微結構狀態調整制約 ,而土粒尺寸和取向的非均勻化發展以及微觀損傷的再擴大是已加固土體強度降低的主要原因。