铁道部第一设计院物探队,利用在含水构造的粘土类围岩上观测到负的二次场值和在含砂层顶部观测到正的二次场值,二者出现明显的正、负差异为物质前提,确定了用二次时差法找水的方法。生产实践表明,这对其它方法无能为力的特殊地区有独特效果。然而这种方法从原理上还难以解释。本 The first design institute of the Ministry of Railways geophysical team, the use of clay in the water-bearing structure of the clay on the observation of the second field and negative on the top of the sand observation of the positive quadratic field, the two showed significant positive and negative Differences for the material premises, identified by the second time difference method to find water. Production practices show that this has a unique effect on special areas that other methods can not afford. However, this method is difficult to explain in principle. this