郯庐断裂带宿迁段合欢路土壤氡分布特征与迁移特征的数值模拟

Numerical Simulation of Radon Concentration in Soil of Hehuan Road in Tan Lu Fault Suqian Segment

沿郯庐断裂带宿迁段合欢路布设土壤氡测线并对测得的数据进行分析研究,结果表明研究区域内土壤氡探测结果对断裂带位置、断层类型和特征有较好的指示性。在已知场地地质构造参数、地层岩性特征的基础上,建立土壤氡迁移模型。建立模型时识别了断裂类型和覆盖层分层特征,并讨论了断层内部结构与氡浓度取值,使模型与实际情况相等。数值模拟结果印证了土壤氡异常峰区间在圈定断裂位置和断层破碎带中的重要作用,揭示了氡在不同覆盖层中的迁移速度,并定量解释了合欢路场地断层土壤氡异常的成因。

Based on the known geological structural parameters and stratigraphic lithology characteristics of the HeHuan road in the Suqian section of the Tan Lu fault,a model of soil radon migration is established.The type of fracture and the layered characteristics of overburden are identified during the model establishment,and we discussed the internal structure of the fault and the radon concentration.This makes the model more consistent with the actual situation.The calculated numerical simulation results are very close to the measured radon curve in soil.The result quantitatively explains the main causes of anomalies in soil radon measurement.It’s confirmed that the abnormal form of soil radon is mainly determined by geological structure,the abnormal values are related to the concentration of cross section and the characteristics of overburden rock formation,the migration velocity of radon in different overburden is different,the range of abnormal soil radon peak can indicate the position of breakpoint and the range of relative fracture.