In this paper, the Ground Penetrating Radar (GPR) method was used to characterize concrete tubes and steel/plastic tanks buried in IAG/USP test site. The microwave tomography was used to improve the GPR images, aiming...In this paper, the Ground Penetrating Radar (GPR) method was used to characterize concrete tubes and steel/plastic tanks buried in IAG/USP test site. The microwave tomography was used to improve the GPR images, aiming to retrieve the geometry of the targets. The numerical modeling studies also were done in order to predict the GPR results of the buried targets and to give more reliability to the results interpretation. The targets were installed in the first shallow geophysical test site of the Brazil located at Institute of Astronomy, Geophysics, and Atmospheric Science (IAG) of the University of S?o Paulo (USP). GPR profiles of 200 MHz (shielded bistatic antennas) were acquired along three lines containing concrete tubes and steel/plastic tanks buried in subsoil. The concrete tubes show a hyperbolic reflector for the top, and the vertical tube also presented a reflection on its bottom. The horizontal steel tanks were characterized by a strong GPR reflection on their top. The empty plastic tank shows a strong reflector for the top with normal polarity. On the other hand, the plastic tank filled with water shows a weaker reflector for its top characterized by the inverted polarity of GPR signal when compared with empty plastic tank. The plastic tank filled with water also went characterized by the strong reflection to its bottom, being a good indicative to interpret GPR data on target in subsoil with some types of fluid inside of tank. The results of polarity difference for the top of tank can be used as guide pattern to identify buried tank empty or filled with water. The application of microwave tomography to the GPR data permitted to determine the position and get a good identification of the edges of the targets studied. The numeric modeling presented a good accordance with real data reducing the ambiguities in interpretation of results. These results can be used as a reference, and they can be extrapolated for areas where there is no subsurface information.展开更多
以半地下式LNG储罐的地震响应和桩基础对半地下式LNG储罐的抗震性能影响为研究目的,设计并开展动力离心模型试验,通过对比有桩和无桩储罐的地震响应加速度、摆角、储液晃动波高等差异,验证桩基础对半地下式LNG储罐抗震性能的提升效果。...以半地下式LNG储罐的地震响应和桩基础对半地下式LNG储罐的抗震性能影响为研究目的,设计并开展动力离心模型试验,通过对比有桩和无桩储罐的地震响应加速度、摆角、储液晃动波高等差异,验证桩基础对半地下式LNG储罐抗震性能的提升效果。结果表明:以自振周期为控制参数的大型LNG储罐离心试验设计方法满足设计原则和要求;0.05g、0.1g、0.3g El Centro波荷载下,桩基础减小了储罐罐顶5.0%~36.6%的水平加速度、13.8%~33.6%最大摆角和8.4%~18.8%储液晃动波高等地震响应,桩基础有利于提高半地下式LNG储罐的抗震性能。展开更多
文摘In this paper, the Ground Penetrating Radar (GPR) method was used to characterize concrete tubes and steel/plastic tanks buried in IAG/USP test site. The microwave tomography was used to improve the GPR images, aiming to retrieve the geometry of the targets. The numerical modeling studies also were done in order to predict the GPR results of the buried targets and to give more reliability to the results interpretation. The targets were installed in the first shallow geophysical test site of the Brazil located at Institute of Astronomy, Geophysics, and Atmospheric Science (IAG) of the University of S?o Paulo (USP). GPR profiles of 200 MHz (shielded bistatic antennas) were acquired along three lines containing concrete tubes and steel/plastic tanks buried in subsoil. The concrete tubes show a hyperbolic reflector for the top, and the vertical tube also presented a reflection on its bottom. The horizontal steel tanks were characterized by a strong GPR reflection on their top. The empty plastic tank shows a strong reflector for the top with normal polarity. On the other hand, the plastic tank filled with water shows a weaker reflector for its top characterized by the inverted polarity of GPR signal when compared with empty plastic tank. The plastic tank filled with water also went characterized by the strong reflection to its bottom, being a good indicative to interpret GPR data on target in subsoil with some types of fluid inside of tank. The results of polarity difference for the top of tank can be used as guide pattern to identify buried tank empty or filled with water. The application of microwave tomography to the GPR data permitted to determine the position and get a good identification of the edges of the targets studied. The numeric modeling presented a good accordance with real data reducing the ambiguities in interpretation of results. These results can be used as a reference, and they can be extrapolated for areas where there is no subsurface information.
文摘以半地下式LNG储罐的地震响应和桩基础对半地下式LNG储罐的抗震性能影响为研究目的,设计并开展动力离心模型试验,通过对比有桩和无桩储罐的地震响应加速度、摆角、储液晃动波高等差异,验证桩基础对半地下式LNG储罐抗震性能的提升效果。结果表明:以自振周期为控制参数的大型LNG储罐离心试验设计方法满足设计原则和要求;0.05g、0.1g、0.3g El Centro波荷载下,桩基础减小了储罐罐顶5.0%~36.6%的水平加速度、13.8%~33.6%最大摆角和8.4%~18.8%储液晃动波高等地震响应,桩基础有利于提高半地下式LNG储罐的抗震性能。
