基于电阻率断层扫描技术的土壤砾石体积含量评估

摘要

In order to evaluate the performance of electrical resistivity tomography applied for estimating rock fragments content, the application of estimation approach to volumetric rock fragments content in stony soils was investigated by numerical simulation. The stony soils were assumed to be biphasic medium with rock fragments embedded in fine earth. Electrical resistivity tomography measurements were simulated by using finite difference analyses on numerical models. The rock fragments inside models were non-jointed and random distributed, effect of rock fragments size and soil water condition were taken into consideration. The results show that the effective electrical resistivity is a function of rock fragments content if the resistivity of the two phases is known, this is in agreement with theoretical prediction. The result approves the applicability of electrical resistivity tomography for volumetric rock fragments content estimation. The approach is better applicable for the condition of wet soils, and can be an important tool for soil basic research and provide references for soil classification and quality evaluation.%为了对电阻率断层扫描技术应用于土壤中砾石含量的研究进行评估,该文对此应用进行了数值模拟研究.该研究假设石质土壤为由细土和砾石组成的二相介质,采用有线差分法对所建立土壤数值模型进行了电阻率断层扫描模拟,模型中砾石随机分布且相互独立,过程中对砾石尺寸和土壤中水分情况的影响进行了研究.结果表明对已知二相各自电阻率值的石质土壤,其等效电阻率与其中砾石体积含量相关,数值模拟结果与理论预测结果相符合,验证了电阻率断层扫描技术应用土壤中砾石体积含量估计的可适用性,同时指出在土壤较湿润时为该技术的适宜使用条件.该研究为土壤学分类研究及质量评价提供参考和指导.