【摘要】 洛阳地区砂卵石地层渗透系数经验取值的范围较大,对洛阳地铁1号线车站深基坑的降水设计造成极大困难。为了精确估算渗透系数,利用地铁车站基坑开挖面取得的土样颗粒筛分试验结果,以现场抽水试验求得的渗透系数值为基准,分析了砂卵石地层有效粒径d₁₀与渗透系数k之间的关系,修正了太沙基渗透系数计算经验公式,得到了适用于洛阳地区砂卵石地层的渗透系数计算经验公式。研究结果表明:修正后的渗透系数计算经验公式,可用于估算d₁₀为0.2～0.7 mm时洛阳地区砂卵石地层渗透系数k。勘探孔取土可能造成砂卵石土样中细颗粒缺失,修正渗透系数计算经验公式时应引入粒径级配累计曲线的曲率系数C_c。更多还原

【Abstract】 The empirical value range of the permeability coefficient of the sand-pebble formation in Luoyang area was relatively large,which caused great difficulties in the dewatering design of the deep foundation pit of the stations of Luoyang metro line 1. In order to accurately estimate the permeability coefficient,by using the results of the particle screening test of the soil from the excavation surface of the subway station foundation pits,the permeability coefficient value obtained from the field pumping test was used as a benchmark to analyze the relationship between the effective particle size d₁₀ and the permeability coefficient k of the sandpebble strata. The empirical formula for calculating the permeability coefficient of Terzaghi was modified,and the formula for calculating the permeability coefficient which was suitable for the sand-pebble strata in Luoyang area was obtained. The results show that the modified empirical formula for calculating permeability coefficient can be used to estimate the permeability coefficient k of sand-pebble strata in Luoyang area when d₁₀ is between 0.2 ～ 0.7 mm. Since the extraction of soil from the exploration hole may cause the loss of fine particles in the sand-pebble samples,the curvature coefficient C_c of the particle size gradation cumulative curve should be introduced to modify the permeability coefficient calculation formula.更多还原