碳酸盐岩红土风化剖面的淋滤试验研究——以贵州遵义和平坝剖面为例

LEACHING EXPERIMENT ON RESIDUAL WEATHERING CRUST OF CARBONATE ROCK --A Case Study of Pingba and Zunyi Profiles of Guizhou

采用人工配制的饱和碳酸水溶液对贵州省安顺、遵义两个典型红土风化剖面的样品柱 ,在常温、常压下进行长约 10 0小时的淋滤试验。对溶液中 10种元素进行检测表明 :石灰岩及其溶滤层比白云岩及其溶滤层 Ca、Mg的溶出量大 2～ 5倍 ;成土物质 Al、Si、Fe、Mn等元素有微量的溶出 ,且红土化程度较低的石灰岩风化剖面较红土化程度较高的白云岩剖面的溶出量大几倍 ,遵义剖面在碳酸水的淋滤下发生较明显的脱 Si作用。试验前后淋滤液的酸度值发生显著变化 ,p H值由4.12～ 4.17变为 6 .86～ 8.0

The sample columns from two typical profiles of weathering crust at Pingba and Zunyi in Guizhou were leached respectively with artificially saturated carbonic water. The test was completed under normal temperature and pressure, and the test time lasted for approximately 100 hours. It is shown from the detection of ten elements in the leaching solution that the dissolution amount of Ca and Mg from limestone and its leaching layer was 2 to 5 times larger than the one from dolomite and its leaching layer. Edaphogenic elements, such as Al, Si, Fe, and Mn etc., were dissolved out in tiny amount. In contrast, the dissolution amount of limestone profile with lower weathering was several times larger than the one of dolomite profile with higher weathering. It is obvious that the desilication at the Zunyi profile occurred due to leaching of carbonic water. pH values change apparently after the test, ranging from 4.12～4.17 to 6.86～8.09.