基于易损性分析的可液化场地单桩基础抗震性能研究  

Study on Seismic Performance of Single Pile Foundations in Liquefiable Sites Based on Vulnerability Analysis

作　　者：许晓帅 贾科敏 许成顺[1] 杜修力[1] XU Xiaoshuai;JIA Kemin;XU Chengshun;DU Xiuli(Key Laboratory of Urban Security and Disaster Engineering of the Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《防灾减灾工程学报》2024年第5期1094-1105,共12页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金面上项目(52078016);国家自然科学基金杰出青年基金(52225807)资助。

摘　　要：桩基础是可液化场地中常用的深基础形式,广泛应用于近海港口、大型建筑等,资料表明可液化场地中地震引起的桩基础损伤破坏案例屡见不鲜。为了评估单桩基础的抗震性能,针对可液化场地单桩基础离心机试验,借助OpenSees计算平台建立了动力相互作用有限元数值模型,并将结果与已有的试验进行比较,验证了模型的有效性。基于此,重点分析了场地液化、上覆硬土层、上部结构对体系地震响应及桩基础抗震性能的影响。以桩头位移及曲率作为抗震性能指标并采用推覆分析获取桩在不同损伤状态下地震易损性抗震性能指标的界限值,以PGA作为地震动强度指标,基于云图法建立了概率地震需求模型,进而绘制了桩基础的地震易损性曲线,评估了不同性能状态的损伤概率。结果表明:土体液化、上覆硬土层及上部结构均增加了桩的曲率、位移需求和桩基础的损伤破坏概率。Pile foundations are a common form of deep foundations in liquefiable sites,with widespread applications in coastal ports and large buildings.Evidence suggests that cases of pile foundation damage caused by earthquakes in liquefiable sites are common.To evaluate the seismic performance of single pile foundations in liquefiable sites,a dynamic interaction finite element numerical model was established using the Opensees computational platform,based on centrifuge tests.The results were compared with existing experimental data to verify the model's validity.Based on this,the effects of soil liquefaction,overlying hard soil layers,and superstructure on the seismic response of the system and the seismic performance of pile foundations were analyzed.Pile head displacement and curvature were used as seismic performance indicators,and pushover analysis was employed to obtain the threshold values of seismic vulnerability under different damage states.Peak Ground Acceleration(PGA)was utilized as the intensity measure for seismic motion.A probabilistic seismic demand model was developed using cloud analysis,which led to the creation of vulnerability curves of pile foundations,assessing the damage probability for different performance states.The results showed that soil liquefaction,overlying hard soil layers and superstructure all increased the curvature and displacement demands on the pile,and the damage probability of pile foundations.

关 键 词：桩基础 液化场地 抗震性能 响应规律 易损性分析 

分 类 号：TU375[建筑科学—结构工程]