大气影响下平顶山膨胀土地表蒸发研究

Study on surface evaporation of Pingdingshan expansive soil under atmospheric effect

为探索膨胀土的蒸发特征,对平顶山市区膨胀土进行了不同初始含水量土体的室内和室外蒸发试验,测试了蒸发过程中土体含水量在不同深度的变化。对室内、外试验结果及其差异性进行了分析,发现室内和室外土样的蒸发强度差别较大,但是蒸发系数相差不大,蒸发系数与土体含水量、含水量梯度有较强的相关性。地表土体接近饱和时,蒸发系数在1上下波动。随着蒸发的持续,蒸发系数随地表含水量降低而下降,含水量梯度随地表含水量的降低而升高。当地表含水量达到残余含水量时,含水量梯度达到极大值,持续蒸发下含水量梯度将继续减小。对土体蒸发系数与蒸发历时进行拟合,呈较好的对数关系。

The expansive soil is sensitive to climate.In this study,the indoor and outdoor evaporation experiments on Pingdingshan expansive soil with various initial water contents have been studied.The variation of soil water content with depth in the evaporation process has been obtained.The evaporation intensity is different between indoor and outdoor soil specimens,but their evaporation coefficient is less different.The evaporation coefficient has correlation with soil water content and water content gradient.When the surface soil is close to saturation,the evaporation coefficient fluctuates around one.With continuous evaporation,the evaporation coefficient decreases with the surface water content,and the water content gradient increases with the decrease of surface water content.When the surface water content reaches the residual water content,the water content gradient reaches the maximum.The continuous evaporation water content gradient will gradually decrease.A good logarithmic relationship between the evaporation coefficient of soil and the evaporation duration can be seen.