边坡条件对重力式挡墙地震位移模式的影响

Influence of Slope Conditions on Seismic Displacement Modes of Gravity Retaining Wall

基于大型振动台模型试验,研究边坡条件对重力式挡墙地震位移模式及其变化方式的影响。振动台模型试验采用2个比尺1∶8的基覆边坡和顺层边坡模型,支挡结构为重力式挡墙与格构式锚杆框架二级组合式结构,地震波选用大瑞人工波和Kobe波。研究表明,基覆边坡中重力式挡墙地震位移模式主要有4类,即绕墙趾向边坡外侧转动、以滑动为主的向边坡外侧滑动与绕墙趾向边坡外侧转动的耦合、以转动为主的绕墙趾向边坡外侧转动与向边坡外侧滑动的耦合以及以滑动为主的向边坡外侧滑动与绕墙踵向边坡方向转动的耦合。顺层边坡中重力式挡墙地震位移模式主要有2类:绕墙趾向边坡外侧转动,绕墙趾向边坡外侧转动与离开边坡土体向外侧滑动的耦合。当地震烈度大于VII度时,重力式挡墙才产生动位移模式。边坡条件、地震波类型及烈度对重力式挡墙地震位移模式及其变化方式的影响较大,对相对位移的影响较小。

Based on large-scale shaking table model tests,the influences of slope conditions on seismic displacement modes of gravity retaining wall and its change mechanism are studied.Two-step retaining types with gravity retaining wall and anchored lattice frame structure are used as slope retaining structures,and two slope models including base-rock slope and bedding rock slope with geometric scale of 1:8are designed for large-scale shaking table model tests,Darui synthetic seismic wave and Kobe seismic wave are employed as the earthquake loads for the excitation of two slope models.T Four types of seismic displacement modes of gravity retaining walls of base-rock slope are:the outward rotation to the base,the slide-based coupling of the sliding from the slope and outward rotation to the base,the rotation-based coupling of the outward rotation to the base and sliding from the slope,the slide-based coupling of the sliding from the slope and the inward rotation to the base.Two types of seismic displacement modes of gravity retaining walls of bedding rock slope are:outward the rotation to the base,the coupling of the outward rotation to the base and sliding from the slope.The seismic displacement mode of gravity retaining wall occurs when the earthquake intensity is larger than VII.The slope condition,seismic wave type and its intensity have great influence on the seismic displacement modes and its change mechanism,but have slight influence on the relative displacement values of gravity retaining wall.