Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the c...Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang＇an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of crosssectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general.展开更多
时域介质响应数学模型的合理构建及其参数辨识的准确性对评估油纸绝缘老化状态至关重要。针对原有模型未能真实反映极化过程,引入了微观动力学的线型因子,建立了非典型线型的介质响应函数;首次提出了二次时域微分解析法用于不同弛豫过...时域介质响应数学模型的合理构建及其参数辨识的准确性对评估油纸绝缘老化状态至关重要。针对原有模型未能真实反映极化过程,引入了微观动力学的线型因子,建立了非典型线型的介质响应函数;首次提出了二次时域微分解析法用于不同弛豫过程的分解,该方法不仅能准确判定极化支路数,而且所提取的谱线特征量,确保了介质响应参数辨识的唯一性。最后,应用该方法对1台220 k V变压器的实测去极化电流曲线进行参数辨识。结果表明,通过改进介质响应数学模型,采用二次时域微分解析法获取的去极化电流曲线与测试曲线更为相符,重合度由传统方法的88.56%提升到97.58%,验证了该方法在油纸绝缘介质响应参数辨识中的适应性和准确性。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.51308012)the Key Laboratory of Transportation Tunnel Engineering+1 种基金Ministry of EducationSouthwest Jiaotong University(Grant No.TTE2014-06)
文摘Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang＇an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of crosssectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general.
文摘时域介质响应数学模型的合理构建及其参数辨识的准确性对评估油纸绝缘老化状态至关重要。针对原有模型未能真实反映极化过程,引入了微观动力学的线型因子,建立了非典型线型的介质响应函数;首次提出了二次时域微分解析法用于不同弛豫过程的分解,该方法不仅能准确判定极化支路数,而且所提取的谱线特征量,确保了介质响应参数辨识的唯一性。最后,应用该方法对1台220 k V变压器的实测去极化电流曲线进行参数辨识。结果表明,通过改进介质响应数学模型,采用二次时域微分解析法获取的去极化电流曲线与测试曲线更为相符,重合度由传统方法的88.56%提升到97.58%,验证了该方法在油纸绝缘介质响应参数辨识中的适应性和准确性。
