江汉平原第四系弱透水层渗透系数求算方法

发布时间：2018-10-13 19:36

【摘要】：弱透水层的渗透系数是区域地下水流系统划分和关键带水-土-生作用的重要参数.结合江汉平原关键带调查采集1∶5万杨林尾-陆溪口图幅钻孔52组不同深度、不同岩性的原状土样,利用改进的渗透仪进行室内渗透实验,对粘性土样的渗透系数和粒度特征参数进行经验公式修正.发现研究区沉积物渗透系数与含水岩组埋深和岩性有关.浅层孔隙潜水含水岩组以粉质粘土、粘土为主,沉积环境稳定,渗透系数约10~(-9) m/s,变异系数为1.56;中深层承压含水岩组夹有多层粘土和粉砂,呈现多旋回分布的典型河湖交互作用的沉积环境,渗透系数为10~(-10)10~(-6) m/s,变异系数为2.04,变异性较大.利用有效孔隙比e_u与黏粒含量P的显著二项式关系,修正预测粘性土渗透系数的太沙基经验公式,预测值与室内实测数据基本吻合,二者比值均小于10,验证了太沙基修正公式在河湖相平原区的适用性.
[Abstract]:The permeability coefficient of the weak permeable layer is an important parameter for the division of regional groundwater flow system and the key water-soil-generation process. Combined with the investigation of critical zone in Jianghan Plain, 52 groups of undisturbed soil samples with different depth and lithology were drilled from the 1: 50 000 poplar tail to Luxikou map, and the laboratory permeation experiments were carried out by using the improved osmometer. The empirical formula was used to modify the permeability coefficient and particle size characteristic parameters of viscous soil samples. It is found that the permeability coefficient of sediment in the study area is related to the buried depth and lithology of the water-bearing rock formation. The shallow pore phreatic water-bearing rock formation is composed of silty clay, stable sedimentary environment, permeability coefficient is about 10 ~ (-9) m / s, variation coefficient is 1.56. The sedimentary environment of typical fluvial and lacustrine interaction with polycyclic distribution has a permeability coefficient of 10 ~ (-10) 10 ~ (-6) m / s and a coefficient of variation of 2.04. Based on the significant binomial relation between effective void ratio (EU) and clay content P, the empirical formula for predicting permeability coefficient of cohesive soil is modified. The predicted value is in good agreement with the measured data in laboratory. The ratio of the two is less than 10, which verifies the applicability of the modified formula in the fluvial and lacustrine plain.
【作者单位】：中国地质大学环境学院;中国地质大学盆地水文过程与湿地生态恢复学术创新基地;
【基金】：中国地质调查局项目(Nos.12120114069301,DD20160255) 国家自然科学基金项目(No.41272258)
【分类号】：P641.2

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