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裂隙易在降雨作用下诱发滑坡等灾害,裂隙的饱和/非饱和渗透特性是研究此类问题的关键。利用精密数控机床制作随机粗糙裂隙面,并研制了一套仪器进行此随机粗糙裂隙的渗流试验,得到了裂隙的饱和渗透系数,然后通过间接方法预测此裂隙的非饱和渗透系数。研究发现,当裂隙平均开度为0.4 mm时,其饱和渗透系数为0.1 m/s。通过立方定律得到的水力等效隙宽为0.35 mm,小于其平均隙宽。同时裂隙的渗透系数与平均隙宽的平方成正比,这与立方定律的趋势相一致。研究得到了不同隙宽裂隙的非饱和渗透系数函数,当基质吸力小于进气值时,渗透系数为一常数,即为饱和渗透系数;当基质吸力大于进气值时,裂隙板的渗透系数急剧减小。当裂隙板的基质吸力达到其残余含水率对应的吸力值时,裂隙板的渗透系数基本稳定。在此情况下,基质吸力的继续增加对渗透系数的影响非常小,很难使渗透系数减小。
Cracks easily induce landslides and other disasters under rainfall. The saturated / unsaturated infiltration characteristics of fractures are the key points to study the problems. The random rough fracture surface was made by the precision numerical control machine tool. A set of instruments was developed to carry out the seepage test of the random rough fracture. The saturated permeability coefficient of the fracture was obtained. Then the unsaturated permeability coefficient of the fracture was predicted by indirect method. The study found that when the average crack opening is 0.4 mm, the saturated permeability coefficient is 0.1 m / s. The hydraulic equivalent gap width obtained by cubic law is 0.35 mm, less than its average gap width. At the same time, the permeability coefficient of fractures is proportional to the square of the average gap width, which is consistent with the trend of cubic law. The unsaturated permeability coefficient function of different width gaps is obtained. When the matrix suction is less than the inlet value, the permeability coefficient is a constant, which is the saturated permeability coefficient. When the matrix suction is greater than the inlet value, the permeability coefficient of the fracture plate is sharp Decrease The permeability coefficient of the fissure plate is basically stable when the substrate suction of the fissure plate reaches the suction value corresponding to the residual moisture content. In this case, the continued increase of the matrix suction has a very small influence on the permeability coefficient, making it difficult to reduce the permeability coefficient.