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在水库现场试验了RIS K2型探地雷达探测水库冰厚度的能力,试验时所用天线频率为600MHz;同步钻孔测量雷达探测处的冰厚度;以及在一个点上取样测试分析冰晶体、冰内气泡和冰密度。试验时冰面积雪厚度0.03-0.05m,冰层上部有0.24m粒状冰,其下均为柱状冰;冰内气泡含量呈表层高底层低分布;冰密度随气泡含量变化;冰厚度在平面内不均一。通过探测厚度和实测厚度的对比分析以及气泡含量对介电系数影响的理论分析,建立了积雪、粒状冰和柱状冰三层介质模型,获取雷达波在冰内的理论传递时间。结果发现:能够利用等效介电常数或等效传播速度评价雷达波传递时间,结冰期冰层1/3深度处的对应介电常数或传递速度可以作为等效值;另外因冰内大气泡造成的理论传递时间大于雷达探测时间,其差值随理论传递时间或冰厚的增加呈非线性增加。
At the reservoir site, the ability of RIS K2 GPR to detect the ice thickness of reservoirs was tested at an antenna frequency of 600 MHz. Simultaneous drilling was used to measure the ice thickness at the radar probe, and at one point, samples were taken to test the ice crystals, Bubbles and ice density. The ice thickness is 0.03-0.05 m in thickness and 0.24 m granular ice in the upper part of the ice layer, with columnar ice underneath. The content of air bubbles in ice is high and low in the surface layer. The ice density varies with the bubble content. The ice thickness is in the plane Inhomogeneous. Through the theoretical analysis of the contrast between the measured thickness and the measured thickness and the influence of bubble content on the dielectric coefficient, a three-layer medium model of snow, granular ice and columnar ice was established to obtain the theoretical transfer time of radar wave in ice. The results show that the equivalent dielectric constant or equivalent propagation velocity can be used to evaluate the radar wave propagation time. The corresponding dielectric constant or transmission velocity at icing depth can be regarded as the equivalent value. In addition, Bubble caused by the theoretical transfer time is greater than the radar detection time, the difference with the theoretical transfer time or ice thickness increased non-linearly.