【作者】 刘礼标；

【导师】 张永兴； 陈建功；

【作者基本信息】 重庆大学 ， 土木工程， 2013， 博士

【摘要】 支挡结构是岩土工程中的一个重要组成部分，具有极其重要的地位。如果能够及时有效地对支挡结构进行健康监测，就可以对支挡结构的整体稳定性进行评估，进而可以避免人民群众的生命财产及国家的巨额基础设施蒙受巨大的损失。因此如何对支挡结构进行健康诊断，以确定支挡结构是否存在损伤，进而判别损伤位置、损伤程度和损伤变化趋势，是岩土支挡结构健康监测与安全评估系统的最主要问题。为此，本文在国家自然基金科学仪器基础研究项目“岩土支挡结构健康诊断仪的研制”(项目批准号：51027004)、教育部长江学者和创新团队发展计划项目“山区岩土工程”（项目批准号：IRT1045）的资助下对轻型挡土墙系统健康诊断问题展开了相关研究。基于理论分析、数值模拟和现场试验，对挡土墙系统的土体附加参数识别、动力指纹损伤识别法、人工智能损伤识别法和整体稳定性评价等问题进行了全面深入的研究，论文的主要研究工作如下：①建立了轻型挡土墙系统动力响应的三维有限元数值模型，运用整体正交多项式法和特征系统实现法对挡土墙系统的模态特性进行研究。为了研究损伤对挡土墙系统模态特性的影响规律，详细分析了土体、挡墙的损伤程度、损伤面积和损伤位置对挡土墙系统的模态特性和幅值谱曲线的影响。②提出了悬臂挡土墙系统的简化动测模型，对土体附加参数的识别方法进行探讨。在模态参数识别的基础上，采用有限元优化设计方法识别土体的附加参数，对不同的组合优化方法、不同的目标函数的识别结果进行评价。并分析了土体附加阻尼对挡土墙系统简化动测模型的模态特性和动力响应的影响。③引入微分几何中的平均曲率概念，推导了适用于轻型挡土墙结构的损伤识别新指标：模态平均曲率差MMCD和柔度差平均曲率FDMC。以悬臂挡土墙为算例，通过与其他三种损伤识别指标(频率变化率RF、振型变化率RD、高斯曲率模态差MGCD)进行对比分析，验证新指标对损伤的敏感性和有效性。损伤识别新指标能够准确的识别出挡土墙的损伤位置，继而评估挡土墙的损伤程度。④采用改进多种群遗传算法，结合挡土墙系统损伤时的特征方程，构造了能有效地同时识别出挡土墙系统损伤位置和损伤程度的方法：整体损伤识别法和分区损伤识别法。通过悬臂挡土墙不同损伤工况的识别结果，对两种识别方法的适用性、识别精度、计算效率和有效性进行了探讨。⑤对挡土墙系统整体稳定性“实时”评价方法进行研究，将挡土墙整体稳定性分为3个等级：稳定、基本稳定和不稳定。在挡土墙系统模态分析基础上，将土体等效成一系列弹簧来模拟，土压力统一表示为静止土压力和土压力增量之和，并假定土压力增量等于土体的地基反力系数和墙体位移的乘积，结合墙土共同变形，进行迭代计算得到土压力的分布形式。通过对库伦土压力理论、静止土压力理论和试验结果进行对比分析，验证所提出的土压力计算方法的可行性，从而进一步确定挡土墙系统的整体稳定性。更多还原

【Abstract】 Retaining structure is an important part in geotechnical engineering, has theextremely important status. If the health diagnosis of retaining structure is conducted ina timely and effective, can evaluate the overall safety of retaining structure, which willavoid the people’s life and property and the infrastructure suffered huge losses.Therefore the health diagnosis of the retaining structure is the most major problem inthe health monitoring and safety assessment system of retaining structure, in order todetermine whether the retaining structure is damage, damage location, damage degreeand trends of damage. In this paper, the research of health diagnosis is carried out on thelight retaining wall, based on the project of “development of health diagnosis instrumentfor geotechnical retaining structure”(No.51027004) for the national natural sciencefoundation instruments basic research project and the program of “Mountainousgeotechnical engineering”(No.IRT1045) for the changjiang scholar and innovativeresearch team, the added parameters identification, identification method of dynamicsignature, damage identification method of artificial intelligence and global stabilityevaluation of retaining wall system was studied. In this dissertation, the main originalwork includes:①In order to study modal characteristics and dynamic response of retaining wallsystem, the three-dimensional numerical model is established using finite elementmethod. The characteristics of retaining wall system modal were studied by integralorthogonal polynomial method and eigensystem realization algorithm.The influence ofsoil damage or retaining wall damage is researched on the modal characteristics and theamplitude spectrum curve of retaining wall system.②The dynamic-detection model is established to the health diagnosis of cantileverretaining wall system. At the same time, the added parameters of the soil are discussedin detail. Based on modal parameter identification, optimization design by finiteelement is proposed to identify added parameters of the soil. The identification resultsof added parameter were evaluated, which is calculated by different combinatorialoptimization methods and the different objective function. And the influence of themodal characteristics and dynamic response are analyzed on added damping of soil.③The modal mean curvature difference (MMCD) and flexibility-difference meancurvature (FDMC) is proposed. By a numerical simulation of cantilever retaining wall, comparative analysis with frequency rate (RF), the variation rates (RD), Gaussiancurvature mode difference (MGCD), to verify the sensitivity and effectiveness of thenew damage index.④Overall damage identification method and partition damage identificationmethod was proposed based on improved multiple population genetic algorithm anddamage characteristic equation of retaining wall system. The method can identify thedamage location and damage degree of retaining wall system effectively. Theapplicability, recognition accuracy, computational efficiency and validity of the twomethods are discussed by a numerical simulation of cantilever retaining wall.⑤The real-time evaluation method of global stability was studied on retainingwall system. The global stability is divided into three grades: stable, basically stable andunstable. A new method was proposed based on modal test and parameter identification.The soil is equivalent to a set of springs, and the earth pressure is expressed as the sumof the static earth pressure and the increment of earth pressure. The increment of earthpressure is assumed to the coefficient of subgrade reaction by the wall displacement.Combined with common degeneration theory, the earth pressure distribution form isobtained by iterative calculation. By comparing the calculation results with thecoulomb’s earth pressure theory, static earth pressure and the experimental ones, thefeasibility of the proposed method is validated. To further determine the global stabilityof the retaining wall system.更多还原