重力式挡土墙抗震稳定性检算最不利状态选取探讨OA北大核心CSTPCD
Exploration on Selection of the Most Unfavorable State for Seismic Stability Calculation of Gravity Retaining Walls
重力式挡土墙整体稳定性检算最不利状态选取对抗震设计有重要影响.针对加速度峰值、墙身外倾峰值、墙顶位移峰值三种典型挡墙抗震危险时刻以及常用"土压力峰值时刻包络"取值方法,以振动台模型试验揭示地震土压力取值结果差异性,基于重力式挡土墙ABAQUS有限元模型地震响应计算,分析各危险时刻墙背土压力取值及整体稳定性检算结果差异,提出抗震稳定性检算最不利状态建议.结果表明:(1)随地面峰值加速度和墙高增加,三种危险时刻地震土压力均呈现从非线性分布向近似正三角图式转化,合力及作用点高度整体上较现行抗震规范分别大49%和18%;(2)峰值包络法因不能反映墙-土运动主/被动状态和地震动传导时延特征,致使墙顶附近土压力取值结果过大,地震土压力合力较危险时刻大一倍且作用点偏高约25%;(3)墙身外倾峰值危险时刻的抗滑移稳定系数较其余两种危险时刻偏小14%～33%,且随地面峰值加速度增大反映出更明显的衰减敏感性,以此作为抗震稳定性检算最不利状态有利于结构安全与经济性协调.
The selection of the most unfavorable state in the overall stability calculation of gravity re-taining walls has an important influence on seismic design.Shaking table model tests were used to re-veal the differences in seismic earth pressure values at three critical seismic moments for retaining walls,namely,peak acceleration,peak outward rotation of the wall,and peak displacement at the top of the wall.Also,an evaluation of the envelope method,commonly used to select values at the peak earth pressure moment,was conducted.Based on the seismic response calculations of gravity retain-ing walls by the ABAQUS finite element model,the differences in earth pressure values at the back of the wall and the overall stability calculation results at each critical moment were analyzed,and the most unfavorable state in seismic stability calculation was proposed.Research showed that:(1)With the increase of peak ground acceleration and wall height,the seismic earth pressure at the three critical moments all showed a transition from a non-linear distribution to an approximately equilateral triangu-lar pattern.The combined earth pressure and the height of its action point were,on average,49%and 18%greater,respectively,than those in the current seismic design codes.(2)Due to the inability of peak envelope method to reflect the active/passive state of wall-soil motion and the seismic wave prop-agation delay,the earth pressure values near the top of the wall were overly high,and the combined seismic earth pressure was twice as large as that at the critical moments,with the action point about 25%higher.(3)The anti-slide stability coefficient at the moment of peak wall outward rotation was 14%～33%smaller than the other two,and the sensitivity to attenuation was more obvious with the increase of peak ground acceleration.Therefore,selecting the critical moment of peak wall outward ro-tation as the most unfavorable state in seismic stability calculation is deemed to achieve a balance be-tween structural safety and cost-effectiveness.
张瀚文;蒋良潍;杜美玲;葛学军;杨芸
西南交通大学土木工程学院,四川 成都 610031||西南交通大学高速铁路线路工程教育部重点实验室,四川 成都 610031中铁二院工程集团有限责任公司,四川 成都 610031
土木建筑
重力式挡土墙抗震设计整体稳定性最不利状态有限元分析
gravity retaining wallseismic designoverall stabilitythe most unfavorable statefinite el-ement analysis
《防灾减灾工程学报》 2024 (002)
372-380 / 9
国家自然科学基金项目(52078435)资助
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