ECC桩锚支护体系在地震作用下的动力响应特性研究  

Study on the dynamic response characteristics of ECC pile-anchor retaining structure under earthquake

作　　者：任寄瑜 谌建霖 丁选明[1] 刘学成 REN Jiyu;SHEN Jianlin;DING Xuanming;LIU Xuecheng(School of Civil Engineering,Chongqing University,Chongqing 400045,China)

机构地区：[1]重庆大学土木工程学院,重庆400045

出　　处：《铁道科学与工程学报》2024年第10期4089-4100,共12页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52178312);重庆市自然科学基金创新群体科学基金资助项目(cstc2020jcyj-cxttX0003)。

摘　　要：传统混凝土材料的桩锚支护结构在地震作用下常出现一些难以修复的损伤和破坏。提出以工程水泥基复合材料(Engineered Cementitious Composite,ECC)的桩板墙代替传统混凝土材料(Reinforced Concrete,RC)的桩板墙,形成ECC桩锚支护结构。ECC是一种具有高延性、高韧性和多缝开裂等特征的纤维增强水泥基复合材料,具有较好的抗震性能,在桥梁工程、结构工程中有大量应用,但ECC桩锚支护结构的抗震性能尚不明确。由此,针对ECC桩锚支护结构,开展振动台模型试验,对比RC桩锚支护结构在抗震性能方面的差异性,分析坡体加速度放大效应、桩后动土压力、桩身变形以及锚索动轴力响应,探究ECC桩锚支护体系的动力响应和破坏特征。结果表明:在同等强度的地震荷载作用下,ECC桩锚结构的桩顶位移和桩身拉裂缝长度均小于RC桩锚。相较之下,RC桩锚受拉侧出现贯通裂缝并且逐渐向受压侧发展。2种结构的动力响应具有相似的分布规律和发展趋势,在动力作用下均表现出较明显的弹性和弹塑性阶段,但随着地震输入峰值加速度的增大,ECC桩锚的加速度响应、桩后动土压力峰值以及锚索峰值轴力均显著小于RC桩锚。从桩锚结构的桩顶残余位移来看,残余位移随PGA呈现指数分布,RC桩锚的桩顶位移是ECC桩锚的1~1.5倍。The pile-anchor retaining structures of traditional concrete material often suffer from unrepairable damages and destructions under earthquake conditions.In this study,we proposed replacing the pile-slab walls of traditional concrete material(RC)with those of Engineered Cementitious Composite(ECC)material to form the ECC pile-anchor retaining structures.ECC is a type of fiber-reinforced cementitious composite material with characteristics of high ductility,high toughness,and multi-seam cracking.It exhibits excellent seismic performance and has extensive applications in bridge and structural engineering.However,the seismic performance of ECC pile-anchor retaining structures remains unclear.Therefore,shaking table tests were conducted on the ECC pile-anchor retaining structure to compare the differences in seismic performance of RC concrete pile-anchor retaining structures,and the amplification effect of the acceleration of the slope,the dynamic soil pressure behind the piles,the deformation of the piles,and the responses of the dynamic axial force of the anchor cables were analyzed to investigate the dynamic responses and damage characteristics of the ECC pileanchor support system.The results showed that the pile top displacement and the length of pile tensile cracks of the ECC pile-anchor structure were smaller than those of the RC pile-anchor under the same earthquake.In contrast,penetrated cracks appeared on the tension side of RC pile anchors and gradually developed to the compression side.The dynamic responses of the two structures showed similar distribution and development trend,and they all showed obvious elasticity and elastic-plasticity phases under the dynamic load.However,the acceleration response of the ECC pile anchors,the peak dynamic soil pressure behind the pile and the peak axial force of the anchor cable were all lower than those of the RC pile anchors,as the peak ground acceleration(PGA)of seismic input increased.In terms of the residual pile top displacement of the pile-anchor structure,the re

关 键 词：工程水泥基复合材料 桩锚支护结构 振动台试验 动力响应 抗震性能 

分 类 号：TU435[建筑科学—岩土工程]