石灰岩与白云岩坡地多重介质土壤颗粒运移及其机制

石灰岩和白云岩连续分布区是石漠化防治的重点和难点区。虽然遥感证实了石灰岩区石漠化程度明显高于白云岩区，但造成这种差异的水土流失机理解释尚不明确，这影响了针对不同岩性背景的侵蚀阻控技术的研发。为此，项目通过物探和钻探，借助三维模型量化白云岩与石灰岩坡地地表地下结构差异；基于物探成果，应用一孔多层观测系统，在坡面尺度实现地表和地下多重介质（基质-裂隙-管道）水文-土壤颗粒-水化学过程的协同监测；在此基础上，估算不同介质的侵蚀贡献以及新旧水比例和土壤颗粒物质来源，探明两种岩性坡地土壤的主要流失途径和水文驱动力；通过相关分析，明确影响地表地下产流产沙的主控因子，从岩性影响岩溶介质分异及介质结构控制下的水动力学两方面，阐明石灰岩与白云岩坡地土壤颗粒运移机制差异及成因，并改进Varkarst模型用于喀斯特坡地侵蚀模拟。研究结果对于揭示喀斯特坡地多重介质水土流失机理和实现石漠化防控精准布局具有重要意义。

The continuous limestone and dolomite stone areas are the key and tough regions in the implementation of rocky desertification restoration project. Although remote sensing investigations have confirmed that the rocky desertification degree in limestone areas is obviously higher than that in dolomite stone areas, it is still unclear what factors contributed to this differentiation. This in turn has affected the development of runoff and soil loss control measures suitable for specific lithologic background to combat rocky desertification. Therefore, this project will conduct detailed surface survey and geophysical exploration based underground survey, as well as drilling, then use 3D model to further describe and quantify the differences of ground and underground space structure between the dolomite slope and limestone slope. Based on the geophysical results, four sets of continuous multichannel tubing multilevel system (CMT) will be installed at the hillslope scale in both experimental slopes. These monitoring systems can realize the independent and coordinated monitoring of runoff, soil particle concentration, and hydrochemical characteristics on surface and in each individual underground multiple porous media components (matrix-fissure-conduit). On this basis, the erosion contribution rate of different media components, the new/old water ratio and the soil particle sources will be estimated, and the main soil and water loss paths and hydrological driving forces of the two lithologic slopes will be explored. Through correlation analysis, the main controlling factors affecting surface and underground erosion will be identified, and the causes of differences in soil particle migration and its mechanism between limestone and dolomite slopes will be clarified from two perspectives, namely lithology affecting the differentiation degree of karst medium and hydrodynamics under the control of medium structure. Then the Varkarst model will be adjusted and adopted for karstic three dimensional soil and water loss simulation. Through the implementation of this project, two outcomes will be predictable. Firstly, the soil erosion mechanisms in karstic multiple porous media will be further revealed and elaborated, and secondly the accuracy and efficiency of rocky desertification controlling measures will be greatly improved. Thus, the results will be very significant from both theoretical and practical aspects.