液化场地板桩挡土墙抗震性能及地震风险分析 English Version
Seismic Performance and Seismic Risk Assessment of a Sheet-pile Retaining Wall Subjected to Liquefaction-induced Lateral Spreading
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摘要: 地震极易诱发饱和砂土液化及土体侧向大变形，导致滨水区板桩挡土墙倾斜过大、甚至破坏。为了研究砂土液化对板桩挡土墙抗震性能及地震风险的影响，本文采用一种新型的多屈服面弹塑性本构模拟饱和砂土地震液化特性，考虑孔隙水与土颗粒的动力耦合效应，建立液化场地板桩挡土墙试验的有限元分析模型。通过拟合Ottawa砂抗液化强度曲线和板桩挡土墙离心机试验数据，验证了饱和砂土本构和有限元分析模型的准确性。基于试验验证后的计算模型，本文选取了100条地震动记录作为模型输入，考虑地震不确定性因素对板桩挡土墙抗震性能的影响，从有效性、相关性、实用性和效益性等四个方面综合评价了8个常用的地震动强度指标，并选择累积绝对速度(CAV)作为最优地震动强度参数。根据非线性动力响应分析结果，本文构建了液化场地板桩挡土墙结构的易损性曲线和地震风险曲线，在概率理论框架下分析了土体渗透率对板桩挡土墙结构地震风险的影响。通过引入地震风险分析方法，可有效评估液化场地板桩挡土墙的抗震性能，为类似的板桩结构抗震设防提供借鉴和参考。Abstract: Earthquakes may trigger liquefaction in saturated coarse granular soils, causing significant lateral deformations and posing a risk to retaining walls, especially in waterfront areas. To systematically investigate the impact of sand liquefaction on the seismic performance and risk of sheet-pile retaining wall, this study employs a novel multi-yield surface elasto-plastic constitutive model to simulate the liquefaction characteristics of saturated sandy soils during earthquakes. The dynamic coupling effect between pore water and soil particles is systematically considered, and a Finite Element (FE) framework for a sheet-pile retaining wall is created based on a centrifuge test configuration. The accuracy and effectiveness of the soil constitutive model and the FE framework are validated by matching the liquefaction strength curve of the Ottawa sand and centrifuge test results. A total of 100 ground motion records are selected as the base input to develop seismic fragility curves and seismic risk curves of the calibrated sheet-pile retaining wall model subjected to liquefaction-induced lateral spreading. In addition, the cumulative absolute velocity (CAV) is identified as the optimal seismic intensity parameter based on the effectiveness, correlation, practicality, and proficiency. Ultimately, the influence of soil permeability on the seismic performance and seismic risk of the sheet-pile retaining wall is analyzed within the probabilistic framework. Overall, the research outcome provides meaningful insights into the seismic design and mitigation measures of equivalent sheet-pile retaining structures.
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