干湿和冻融循环对压实黄土路用性能影响的试验研究

为研究气候环境对黄土路用性能的影响作用,通过室内CBR试验测定土样在干湿循环和冻融循环条件下的CBR值,分析不同循环条件下的P-L曲线、循环次数与CBR值的关系以及含水率与CBR值的演变规律,试验结果表明:(1)在P-L关系曲线中,循环次数一定时,贯入量随着单位压力的增加而增加;相同单位压力下,循环次数越多,试件强度越低,贯入量越大。(2)在5次干湿循环过程中,CBR值均随着循环次数的增加而降低,干湿循环作用下的CBR值与循环次数呈负线性相关,第2次干湿循环为转折点,CBR值减小值逐步增加,反复干湿循环作用下,基质吸力和孔隙结构特征是相互影响的。(3)冻融循环过程中,冻融循环作用下的CBR值与循环次数成二次方负相关,且有趋于稳定值的趋势。(4)在反复循环过程中,分析得到的变化规律为模拟黄土路基在气候环境影响下的长期演变规律研究以及实际工况提供一定的参考依据。

Experimental Study on the Influence of Dry-wet and Freeze-thaw Cycles on Compacted Loess Road Performance

In order to study the effect of climate and environment on the performance of loess Road, the CBR values of soil samples under dry and wet cycle and freezing thawing cycle were measured by indoor CBR test. The relationship between P-L curves, cycle times and CBR values under different cycle conditions, and the evolution law of water content and CBR value were analyzed. The experimental results showed that: (1) the relation of P-L In a curve, when the number of cycles is fixed, the penetration amount increases with the increase of unit pressure. Under the same unit pressure, the more the cycle times, the lower the strength of the specimen and the greater penetration. (2) during the 5 dry and wet cycle, the CBR value decreases with the increase of the cycle times. The CBR value under the dry and wet cycle is negatively correlated with the cycle times, the second dry wet cycle is a turning point, the decrease of the CBR value increases gradually, and the characteristics of the matrix suction and pore structure are interrelated under the action of repeated dry and wet cycles. (3) during the freeze-thaw cycle, the CBR value of freeze-thaw cycles was negatively related to the number of cycles two times, and tended to be stable. (4) in the process of repeated cycles, the change rules of the analysis can be used to simulate the long-term evolution of the Loess Subgrade under the influence of climate and environment, and provide some reference for the actual working conditions.