摘要
为研究输入波频率对微型桩动力特性的影响规律,以直径D为6cm的微型桩为研究对象,制作相应的钢箱,进行了微型桩-土动力相互作用振动台试验。试验结果表明:输入波的频率对桩身变形模式有很大的影响,随着输入波频率的增加,桩身变形由正弯型过渡为反弯型;当输入波的频率小于或者接近模型固有频率时,桩身的最大位移发生在桩顶处;当输入波的频率超过固有频率较多时,桩身的最大位移发生在埋深约60cm(10 D)处,且在埋深20cm(3.3 D)和170cm(28.3 D)处,桩身分别会出现最大的正向弯矩、负向弯矩;当输入波的频率小于模型固有频率时,桩侧土压力p与桩身位移y的关系接近线性关系,形成的滞回环面积很小,当输入波频率接近或者大于模型固有频率时,滞回环面积则较大。
To study the influence of frequencies of input waves on the dynamic property of micropiles,the micropiles with a diameter of 6cm were cited as examples.The steel boxes used for the shaking table test on the micropile-soil interaction were prepared.The results of the test show that the frequencies of the input waves have considerable influence on the deformation mode of the pile shafts.As the increase of the frequencies of the input waves,the deformation of the pile shafts transformed from positive bending type to negative one.When the frequencies of the input waves were less than or close to the natural frequencies of the model,the maximum displacement of the pile shaft occurred at the pile top.When the frequencies of the input waves were much greater than the natural frequencies,the maximum displacement happened at the location 60m（10D）down the soil,and maximum positive bending moment and hogging moment were observed on the pile shaft respectively at the locations of 20cm（3.3D）and 170cm（28.3D）down the soil.When the frequencies of the input waves were less than the natural frequencies of the model,the relation of the lateral soil pressure pof the piles and the displacement yof the pile shafts was close to linear relation,and the area of hysteresis loop formed was small.Nevertheless,when the frequencies of input waves were close to or greater than the natural frequencies of the model,the area of the hysteresis loop was big.
出处
《世界桥梁》
北大核心
2016年第5期21-25,共5页
World Bridges
基金
国家自然科学基金项目(51278126)
福建省自然科学基金(2013J01187)
关键词
桥梁工程
微型桩
桩-土相互作用
振动台试验
频率
桩身位移
滞回环
土压力
bridge engineering
micropile
pile-soil interaction
shaking table test
frequency
pile shaft displacement
hysteresis loop
soil pressure
