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某些水文地質工作者在计算水文地質试驗结果时,往往以鑽头半径代替鑽孔半径,以致造成很大的错误(最大时可达20％以上)。这样,就不能正确地评价岩层的透水性,不能正确地计算滲透系数及预计流入集水建筑物与矿坑的涌水量。现在对如何确定鑽孔半径提出如下意见,供大家参考。一、鑽孔半径的确定 1.在用鋼砂或鋼粒單独鑽进或混合鑽进时,在岩心与鑽头内壁之间和孔壁与鑽头外壁之间,会造成宽度差不多的环形间隙。我们可以假设二环形间隙径向数值是相等的。由此假设出发,卽得确定鑽孔半径
Some hydrogeologists tend to make large errors (up to 20% or more at maximum) in calculating hydro-geological test results by replacing the borehole radius with the bit radius. In this way, the permeability of the rock formation can not be correctly evaluated, the permeability coefficient can not be correctly calculated, and the inflow of water into the water-collecting structures and pits is estimated. Now on how to determine the radius of the drilling made the following comments for your reference. First, the determination of the radius of the drilling 1. In the use of grit or steel alone drilling or mixed drilling, the core and the inner wall of the bit and between the hole wall and bit outer wall, will result in almost the same width of the ring gap. We can assume that the radial values of the two annular gaps are equal. From this assumption, we must determine the radius of the borehole