喀斯特洞穴通风效应特征变化及其对洞内空气环境的影响研究——以贵州绥阳麻黄洞为例

Characteristics of Ventilation Effect in Karst Caves and Its Influence on Cave Air Environment:A Case Study of Mahuang Cave of Suiyang,Guizhou Province

为探究喀斯特洞穴内部空气变化特征,揭示喀斯特洞穴通风效应时空变化规律及其变化模式,于2016年1月~2019年6月间两个监测周期对贵州绥阳麻黄洞洞内外温度、湿度、CO_(2)浓度以及气压进行为期32个月的数据采集,并基于相关模型进行系统分析,结果表明:(1)麻黄洞存在3种通风模式:限制性通风模式、积极性通风模式和过渡阶段。其中夏季主要为限制性通风模式,洞内外气流交换较弱;冬季主要为积极性通风模式,洞内外气流交换运动明显,春季和秋季处于过渡阶段,两种模式交替存在。(2)洞道结构影响通风模式,同样,通风效应影响洞穴空气环境变化。根据洞道结构和通风效应对洞穴空气环境的影响可以将麻黄洞洞道分为3个部分:空气环境变化较大的1#~5#监测点、空气环境变化逐渐减小的6#~9#监测点以及空气环境稳定的10#~15#监测点。(3)受特殊的洞道结构影响,洞道中6#~9#存在"狭管效应"引起的"峡谷风",使得春秋两季洞道中部存在明显气流。基于模型分析洞穴通风效应及其对洞穴空气环境影响,研究喀斯特洞穴通风模式及其变化特征,对洞穴沉积物形成及气候变化及碳循环模式研究有重要意义。

In order to explore the air flow variation characteristics of karst cave, to reveal the temporal and spatial variation and the change mode of the ventilation effect in karst cave. With two monitoring cycle during January 2016 to June 2019, this study had a 32-month data collection about the temperature, relative humidity, CO_(2) concentration and pressure in Mahuang Cave which located in Suiyang. Base on the mode to analysis, the result shows that there are three ventilation modes in the Mahuang Cave, the limited ventilation mode in the summer, the active ventilation mode in the winter and the transition phase in the spring and autumn. The circulate of air flow is restricted in the summer, active in the winter and some exchange in the spring and autumn. The structure of the cave affects the ventilation mode and the ventilation effect also affects the microclimate. According to the influence of the ventilation effect, the Mahuang Cave can be divided into three parts: 1#-5# monitoring point with air exchange, 6#-9# monitoring point with turbulence and 10#-15# monitoring point with relative stable air environment. Due to the special structure of the cave, there is "gorge wind " caused by " Canyon effect " in the middle of the cave, and there is obvious airflow in the middle of the cave in spring and autumn. Analysis of karst cave ventilation mode and study the mode and variation character of ventilation effect in karst cave, it is of great significance to the study of sediment growth, climate change and carbon cycle model.