[目的] 研究喀斯特土壤的深度和分布,为利用探地雷达(GPR)技术开展喀斯特地区峰丛洼地土壤分布的研究提供理论依据. [方法] 通过室内模拟试验,建立喀斯特地区3种典型质地土壤(砂质黏壤土、黏壤土、粉(砂)质黏土)中探地雷达电磁波波速和土壤含水量的关系式.通过实地测定土壤质地和含水量,选择合适的关系式,对探地雷达图像进行校准、解译,获得土壤深度,并采用开挖法进行验证. [结果] 得到了3种质地土壤中电磁波波速(ν)与含水量(θ)关系的三次多项式.利用该关系式探测的喀斯特土壤理论深度与实地开挖的结果相符,误差为0—10 cm.利用探地雷达软件生成了反映测线下不同位置土壤深度的二维图像和样方内土壤深度分布的三维图像,表明土壤主要分布在0—50 cm. [结论] 利用探地雷达技术探测喀斯特地区土壤深度和分布是切实可行的.
[Objective] To analyze the depth and distribution of karst soil in order to provide theoretical basis for using ground penetrating radar(GPR) in the research on soil distribution in karst peak-cluster depression area. [Methods] Through laboratory simulation experiment, this study established the relationship between GPR velocity of electromagnetic wave and soil water content in three types of soil texture(sandy clay loam, clay loam, silty clay) in karst region. Through the field measurement of soil texture and water content, the GPR image was calibrated and interpreted based on the right formula. Then the soil depth was estimated and verified by excavation. [Results] We found the theoretical models of cubic polynomial relationship between electromagnetic wave velocity(ν) and soil water content(θ) for the three soil textures. It showed that soil depth in the field was consistent with the results estimated with theoretical model, and the error range was 0—10 cm. The 2-dimension images reflecting soil depths in the different location under the survey line and the 3-dimension images reflecting soil depths distribution in the quadrant were generated using GPR software. Soil mainly distributed within the depth of 50 cm. [Conclusion] GPR technology was feasible to detect the depths and distribution of discontinuous soil in karst region.