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基于相似理论,开展了4组桩网结构路基大比例动态模型试验,测试了循环荷载下桩网结构路基的动力响应指标,研究了降雨前、后加载力、加载频率以及循环加载次数对路基的动力响应、桩土荷载分担以及垫层格栅应变的影响。结果表明,降雨后路基动应力和动加速度均会增大,并且在基床内部增速较快,而路堤下部其增长基本趋于稳定;循环加载期间桩土应力比缓慢增大,其受降雨影响敏感,雨后降幅可达56.4%~79.5%;循环加载完成后垫层格栅应变增大,其横向分布特征基本保持不变;土拱形成后路基填高继续增加,路基宽度范围内4桩中心格栅应变增幅较大,峰值出现在边坡中心和路基中心附近,横向分布呈“W”型;两桩中心的格栅应变由路基中心向坡脚处呈“台阶”型递增,而路基宽度与边坡范围的格栅应变差距不断缩小。
Based on the similarity theory, four groups of large-scale dynamic model tests of subgrade with pile-net structure are carried out. The dynamic response indexes of subgrade under pile-supported cyclic loading are tested. The influence of preloading load, loading frequency, Dynamic response, load sharing of pile and soil, and strain of grille. The results show that both the dynamic stress and the dynamic acceleration of subgrade increase after rainfall, and the growth rate in the subgrade is faster than that in the subgrade, while the growth in the lower part of the embankment basically stabilizes. During the cyclic loading, the stress ratio of pile and soil increases slowly, Which is sensitive to rainfall. After rain, the drop can reach 56.4% ~ 79.5%. After cyclic loading, the strain of cushion grille increases and its horizontal distribution remains unchanged. The filling of subgrade after soil arching continues to increase. The strain of pile center grille increases greatly, the peak value appears near the center of the slope and near the center of the roadbed, and the horizontal distribution shows “W” shape. The grid strain of two centers is “step” from the center of subgrade to the foot of slope. Type increases, while the gap between the width of the embankment and the slope of the grating strain continually narrowing.