Experimental Study on the Bearing Characteristics of Composite Retaining Structures under Dynamic Loads

本文通过室内缩尺模型试验，研究了动荷载作用下既有重力式挡土墙与新建桩板墙组合支挡结构的承载特性，探讨了桩间距变化对结构受力性能的影响。试验基于相似理论，设计了三种桩间距(200 mm、350 mm、500 mm)工况，逐级施加动荷载至15 kPa，分析了位移、应变、弯矩、土压力及荷载分担比的变化规律。结果表明，随着荷载增加，结构位移逐渐增大，桩身应力和挡土板应力沿深度先增后减，最大应力出现在悬臂段与锚固段交界处。桩身弯矩随荷载和桩间距增大而增大。桩后土压力随桩间距增大而增加，挡土墙侧向土压力则减小。荷载分担比分析表明，桩间距为200 mm时，组合支挡结构的承载性能最佳。研究为动荷载下组合支挡结构的设计与优化提供了理论依据。This article studies the bearing characteristics of existing gravity retaining walls and newly constructed pile sheet wall composite retaining structures under dynamic loads through indoor scaled model tests, and explores the influence of changes in pile spacing on the structural stress performance. Based on similarity theory, three pile spacing conditions (200 mm, 350 mm, 500 mm) were designed for the experiment, and dynamic loads were applied step by step to 15 kPa. The variation laws of displacement, strain, bending moment, soil pressure, and load sharing ratio were analyzed. The results show that as the load increases, the structural displacement gradually increases, and the stress of the pile body and the retaining plate first increase and then decrease along the depth. The maximum stress occurs at the junction of the cantilever section and the anchorage section. The bending moment of the pile increases with the increase of load and pile spacing. The soil pressure behind the pile increases with the increase of pile spacing, while the lateral soil pressure on the retaining wall decreases. The analysis of load sharing ratio shows that when the distance between piles is 200 mm, the bearing performance of the composite retaining structure is optimal. The study provides a theoretical basis for the design and optimization of composite retaining structures under dynamic loads.