复合式整体刚性面板加筋土挡墙结构行为试验研究

Experimental study on structural behavior of reinforced retaining wall with composite full-height rigid facing

复合式整体刚性面板加筋土挡墙是近年研制的新型加筋土挡墙,其面板由预制混凝土板和现浇混凝土组合而成。依托成昆铁路试验段进行此类加筋土挡墙的现场原位试验,并针对其结构特性提出设计原理。施工过程中,在挡墙内部不同部位安装传感器,进行长期监测。分析施工期和工后挡墙基底垂直应力、墙背土压力、土工格栅应变、基底及墙顶沉降、墙面水平位移的演化规律。在面板完成后发生2次地震,监测了地震前后挡墙的变化,研究地震对挡墙结构行为的影响。结果表明:基底垂直应力和墙背土压力随着填筑的增加,逐渐由线性分布演化为非线性分布。土工格栅沿墙高分布的应变峰值平面形状类似"0.3H法(H为墙高)"破裂面。地震后,基底垂直应力、基底及墙顶沉降和墙面水平位移增大,而墙背土压力和土工格栅应变先增大后减小。

The reinforced retaining wall with composite full-height rigid facing is a new reinforced retaining wall developed in recent years.The wall facing is composed of precast concrete slab and cast-in-place concrete.Based on the test section of Chengdu-Kunming railway,the in-situ tests of the reinforced retaining wall were carried out,and the corresponding design principle was proposed according to its structural characteristics.During the construction,sensors were installed in different parts of the retaining wall for long-term monitoring.The evolutions of vertical stress on basement,earth pressure on wall back,geogrid strain,settlements of basement and wall top,facing horizontal displacement during and after construction were analyzed.Two earthquakes occurred after the completion of the wall facing.The changes of the retaining wall before and after the earthquake were monitored,and the influence of the earthquakes on the structural behavior of the retaining wall was studied.The results show that:with the increase of filling,the vertical stress on basement and the earth pressure on wall back gradually change from linear distribution to nonlinear distribution.The shape of peak geogrid strain surface along the wall height is similar to the"0.3 H(wall height)method"fracture surface.After the earthquake,the vertical stress of basement,settlements of basement and wall top,facing horizontal displacement increase,while the earth pressure on wall back and geogrid strain increase firstly and then decrease.