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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.
The permeability coefficient of the aquitard is an important parameter for the division of the groundwater flow system and the key water-soil-soil interaction in the region. According to the key belt survey of the Jianghan Plain, 1: 50000 Yanglinwei-Luxiukou maps were drilled in 52 groups Depth and different lithology, the permeability experiment and the particle size characteristic parameter of the clay soil were modified by empirical formula by using the improved permeation instrument.It is found that the permeability coefficient of the sediment in the study area is close to that of the water-bearing rock group and Lithology.The shallow pore water-bearing aquifer is dominated by silty clay and clay with a stable depositional environment with a permeability coefficient of about 10 -9 m / s and a coefficient of variation of 1.56. There are multi-layers of clay and silt, showing a sedimentary environment with multi-cycle distribution of typical rivers and lakes. The permeability coefficient is 10 ~ (-10) 10 ~ (-6) m / s, the coefficient of variation is 2.04, Based on the significant binomial relationship between the effective void ratio e_u and the clay content P, the empirical formula for the prediction of permeability coefficient of cohesive soil was revised, and the predicted value was in good agreement with the measured data in the laboratory. Applicability of Shari Correction Formula in Plain of Rivers and Lakes.