粉煤灰改良膨胀土路堤强度及膨胀特性试验研究

Experimental Study on Strength and Expansion Characteristics of Expansive Soil Embankment Improved by Fly Ash

针对膨胀土路基工程中膨胀土的改良问题,研究掺加粉煤灰对膨胀土的改良效果,基于室内土力学相关试验,分析不同粉煤灰掺量对膨胀土改良特性,得到粉煤灰改良膨胀土的抗压强度、胀缩特性及击实特性变化规律。研究结果表明:粉煤灰掺加能够显著改善膨胀土强度,随着粉煤灰掺量增加,膨胀土抗压强度逐渐增加,最大增幅约为39.18%,最优粉煤灰掺量约为30%;掺加粉煤灰有效降低膨胀土自由膨胀率、无荷膨胀率等胀缩性指标,最大降幅可达38%、35%;对于改良膨胀土的击实特性,随着粉煤灰掺量增加,最优含水量及最大干密度逐渐减小。

Aimed at the improvement of expansive soil in expansive soil subgrade engineering,the effect of fly ash on the expansive soil is studied.Based on the indoor soil mechanics test,the improvement of expansive soil with different fly ash content is analyzed.Compressive strength,swelling and shrinkage characteristics and compaction characteristics of expansive soil.The results show that the fly ash can significantly improve the strength of expansive soil,with the increase of fly ash content,the compressive strength of expansive soil increases gradually,the maximum increase is about 39.18% and the optimal fly ash content is about 30%;Fly ash is added to effectively reduce the expansive soil free expansion rate,no expansion coefficient of expansion and contraction indicators,the maximum decline of up to 38%,35%;compaction for improved expansive soil compaction,with fly ash The amount increased,the optimal water content and the maximum dry density decreased gradually.