地下河水人工补给洞穴滴水、碳酸盐(钙)沉积特征及景观恢复探讨

岩溶旅游洞穴碳酸盐岩沉积物景观容易受到污染、风化，为了探讨受污损洞穴碳酸盐沉积物的修复方法以确保岩溶旅游洞穴的可持续发展，对广西桂林七星岩No.15支洞距洞口约150 m长洞段的滴水物化指标、现代碳酸盐岩沉积物进行了为期4年的监测分析。结果表明:（1）该洞段的滴水主要源于抽取地下河水的水柜渗漏及降水补给，地下河水和滴水的电导率、Ca2＋] 、HCO3-]在4个水文年中的变化趋势基本相同，雨季洞穴滴水电导率、Ca2＋] 、HCO3-]等显著降低，降雨稀释效应明显；（2）现代洞穴碳酸盐岩沉积具有明显的季节性变化，雨季洞穴滴水量/速率、碳酸钙沉积速率加快，最大沉积量达0.8 g／半月，洞穴入口约150 m长洞段快速滴水碳酸盐最大沉积量达2～4 g／半月，旱季碳酸盐沉积速率减少，最大沉积量仅为0.4 g／半月；（3）抽取岩溶地下水经由地表补给洞穴滴水可提高滴水的电导率、Ca2＋] 、HCO3-]及CaCO3饱和度，促使大量碳酸盐(CaCO3)快速沉积，实现对洞穴受风化、污染景观的修复，新沉积的碳酸钙(CaCO3)还可以将基岩裂隙和洞穴内破损、破裂的钟乳石重新“粘结”起来，利于洞穴的稳定性。 

Characteristics of cave drip water and modern carbonate (CaCO3) deposits caused by underground river artificial recharge and landscape restoration

The landscape of carbonate (CaCO3) deposits in the karst tourism caves is susceptible to pollution and weathering on carbonate sediments. To ensure the sustainable development of the karst tourism caves, it is necessary to study the methods to repair such contaminated or damaged sediments in these caves. To attain this purpose, continuous monitoring and analysis for four years were made to chemical properties of the underground river, cave drips, and modern carbonate sediments in the No.15 branching cave of Seven Star Cave, Guilin, Guangxi Province. The results show that the change trends of conductivity, Ca2+ and HCO3- from the underground river and cave drip water are basically the same during this period. The conductivity, Ca2+ and HCO3- of cave drip water decreased significantly and the rainfall dilution effect is obvious during rainfall seasons. The modern carbonate (CaCO3) deposits in the cave have obvious seasonal variations, where cave drip water amount, drip rate and calcium carbonate deposit rate during rainy seasons accelerate. The largest amount of deposit is 0.8 g/ half month. The largest amount of calcium carbonate deposit from rapid drip water from the cave entrance to about 150 m within the cave passage is up to 2-4 g/half month. The carbonate deposit rate during dry seasons reduces with the maximum only 0.4 g half month. The recharge of cave drip water by extracting the karst underground river can enhance the conductivity, Ca2+], HCO3-] and CaCO3 saturation of cave drip water, rapidly prompting a large number of carbonate (CaCO3) deposits, and realizing restoration of the cave landscape damaged. Besides, new calcium carbonate deposit can also rebind bedrock fissures and damaged / broken speleothem and cave stalactites, which is favorable for the stability of the cave.