冻融作用下二灰黄土强度特性

Strength properties of lime-fly ash loess under freezing-thawing cycles

进行了二灰黄土饱水强度试验、不同龄期二灰黄土在6次冻融循环作用下的强度试验和不同龄期二灰黄土在1次冻融循环后的强度增长试验,分析了二灰黄土的强度特性。分析结果表明:二灰黄土强度随龄期增长而缓慢增大,长龄期二灰黄土饱水强度仅降低2.4%;低龄期二灰黄土经过1～6次冻融循环后,强度平均降低19.0%,长龄期二灰黄土强度基本不变,只降低了2.4%;低龄期二灰黄土经历6次冻融循环后,饱水强度平均降低47.9%,4次冻融循环平均降低41.9%,长龄期二灰黄土经历6次冻融循环后,饱水强度平均降低14.6%,4次冻融循环平均降低7.5%;3、7、14、28d龄期的二灰黄土经历1次冻融循环再养护至90d,长龄期强度只下降了4.0%;长龄期二灰黄土已经初步完成60%的强度增长,具良好的水稳定性和较好的冻融稳定性,可以在冻土地区作为路基的底基层。

For lime-fly ash loess, the water-saturated strength test, the strength test at different ages under 6 freezing-thawing cycles and the strength increasing test after 1 freezing-thawing cycle were carried out, and the strength properties were analyzed. Analysis result shows that the strength of lime-fly ash loess grows slowly with age, and the water-saturated strength of long age lime-fly ash loess only reduces by 2.4%. The strength of early age lime-fly ash loess after 1 to 6 freezing-thawing cycles decreases by 19.0% evenly. The strength of long age lime-fly ash loess after 6 freezing-thawing cycles is essentially same, and only decreases by 2.4%. The watersaturated strength of early age lime-fly ash loess decreases by 47.9% evenly after 6 freezing-thawing cycles, and the strength average decreases by 41.9% after 4 freezing-thawing cycles. The water-saturated strength of long age lime-fly ash loess decreases by 14.6% evenly after 6 freezing-thawing cycles, and the strength average decreases by 7.5% after 4 freezingthawing cycles. When the lime-fly ash loesses with 3, 7, 14, 28 d ages under 1 freezing-thawing cycle are conserved to 90 d, the long age strength average decreases by 4.0%. Therefore, the long age lime-fly ash loess has completed 60% of strength increase, and has better water stability and freezing-thawing stability. 3 tabs, 14 figs, 16 refs.