复合加筋路堤边坡振动台模型试验

摘要

废旧轮胎、三向土工格栅等新型筋材用于岩土工程加筋,经济环保且力学性能优良.采用振动台模型试验,分别对未加筋边坡、三向土工格栅边坡、废旧轮胎串与三向土工格栅复合加筋边坡、轮胎串与轮胎碎片复合加筋边坡模型在地震作用下的动力响应性能进行了研究,探讨了边坡结构在不同地震波形输入、不同加速度峰值和不同加筋方式下,未加筋边坡与复合加筋边坡的加速度分布规律.试验结果表明:加筋方式对加筋抗震效果影响比较显著,同种加筋方式的加速度响应效果在不同地震波作用下规律相近;三向格栅、三向格栅与轮胎串复合加筋、轮胎串与轮胎碎片复合加筋在汶川波激励下,其加速度放大倍数较未加筋边坡相比,最大减小幅度分别为37.5％、30.0％、21.0％,前者加速度放大倍数减小幅度分别是后两者的1.4倍和2倍;不同加筋方式下,边坡的加速度放大倍数随地震激励水平的提高呈非线性增加,但与未加筋边坡相比,随输入加速度峰值增大而呈现明显的增幅递减趋势;各种加筋土边坡与未加筋边坡加速度放大倍数均沿坡面约1/3高程处随高度增加而逐渐增大,并在靠近边坡顶部位置达到最大值.迁安波产生的加速度响应明显强于其他3种地震波的激励.%Waste tires and triaxial geogrids can be used as new reinforcement materials in geotechnical engineering,with merits of excellent mechanical performance,economy and environmental friendliness.Shaking table tests were conducted to study the dynamic performances including distribution of acceleration amplification factor under various conditions such as different earthquake waves,peak ground accelerations (PGA) and reinforcement methods.The slope models include unreinforced slope,triaxial geogrid reinforced slope,triaxial geogrid-waste tire composite reinforced slope,waste tire-tire shred composite reinforced slope.The experimental results show that the seismic performance of the reinforced slopes is significantly improved.Compared with unreinforced slopes,the maximum decrease of acceleration magnification for triaxial geogrid reinforced slope is 37.5％,30.0％ for triaxial geogrid-waste tire composite reinforced slope and 21.0％ for waste tire-tire shred composite reinforced slope under Wenchuan wave excitation.The average acceleration magnification reduction of triaxial geogrid reinforced slope is 1.4 and 2 times greater than those of the latter two types of the slopes.Acceleration amplification factor of the reinforced slopes increases with the seismic excitation in a nonlinear way.Compared with the unreinforced slopes,the increasing amplitude of acceleration amplification factor decrease with the input of PGA.Along the surface of the slope about 1/3 of the slope elevation,acceleration magnification factor of the reinforced slopes increase gradually with the elevation,and reaches the maximum at the slope top.The acceleration response induced by Qianan wave is significantly stronger than those induced by other three types of seismic excitations.