高填方网格状立体格栅加筋土挡墙的地震灾变机理及防控对策

加筋土挡墙具有施工便捷，成本低，占地少等优点，然而业界对加筋土挡墙的地震灾变机理缺乏统一认识，对其抗震设防措施也缺乏系统研究，严重制约了加筋土挡墙在高填方工程中的应用。本项目拟采用3D打印技术制作网格状立体格栅，并对该类格栅与粗颗粒土进行单向直剪试验，分析格栅横肋厚度，纵肋、横肋间距等对界面剪切强度的影响，对立体格栅尺寸参数进行优化；采用最优的格栅与粗颗粒土进行大型循环直剪试验，模拟地震发生时加筋土挡墙筋土界面的相互作用，研究筋土界面的循环剪切特性，建立反映筋土界面动力相互作用机理的理论模型，并与试验结果对比验证其正确性；采用最优格栅建造高填方网格状立体格栅加筋土挡墙模型，通过大型振动台试验研究该类挡墙在地震作用下的失效机理，并采用FLAC3D软件建立该类挡墙的三维地震动力响应分析模型，对影响挡墙抗震性能的关键因素进行分析，提出相应的抗震设防对策，为推广和应用该类挡墙提供系统理论和方法。

Reinforced soil retaining wall has been widely used in construction due to its convenience, low cost, and less land occupation. However, there is no unanimous understanding of failure mechanism for reinforced soil retaining wall under seismic loading. And the seismic fortification measures of reinforced soil retaining wall are not enough to avoid earthquake disaster. All of that seriously restricted the application of reinforced soil retaining wall in high filled engineering. This project intends to use 3D printing technology to produce a new kind of latticed 3D-geogrid. A series of monotonic direct shear tests will be performed on the interface between the 3D-geogrid and coarse-grained soil to select the best 3D-geogrid samples by comparing and analyzing the influence of transverse rib thickness, spacing and other factors on shear strength of the interface. Then cyclic direct shear tests will be carried out on the interface between the best 3D-geogrid and coarse-grained soil to study the laws of shear stress variation and volume change of the soil-geogrid interface under seismic loading. A theoretical model reflecting the dynamic interaction of soil-geogrid interface will be established and compared with the test results to verify its correctness. The best 3D-geogrid will be used to construct multiple high-filled reinforced soil retaining wall models. The failure mechanism of high-filled reinforced soil retaining wall under seismic loading will be studied through large-scale shaking table tests. The 3D dynamic analysis under seismic loading will be established by FLAC3D. The key factors affecting the seismic behavior of the retaining wall will be analyzed, and the corresponding antiseismic recommendations will be proposed. The results obtained from this study could provide systemic theories and methods for popularization and application of this kind of reinforced soil retaining wall.