反裹式加筋砂挡墙离心模型试验研究

摘要

The geotechnical centrifuge model test of the anti-wrapped reinforced sand retaining wall by wire screens and fiber screens was taken to analyze the changes of the settlement of the wall top,the horizontal displacement of the wall face,the earth pressure in the wall and the strain of the reinforcement when the centrifugal acceleration increased,in order to provide the basis for the design and construction of anti-wrapped reinforced sand retaining wall.The test results show that anti-wrapped reinforced sand wall models reinforced by the two kinds of reinforced materials have good overall stability.The geogrid will play a significant role in the reinforcement function when the anti-wrapped reinforced sand wall results in uneven settlement and deformation outward.If the geogrid with higher modulus and stronger resistance to deformation is chosen,the wall settlement and horizontal displacement can be more effectively reduced to ensure that the pavement structure on the top of the anti-wrapped reinforced sand retaining wall will not result in cracking damage of instability because of excessive settlement and horizontal displacement of sand filling roadbed.Simultaneously, in order to avoid the anti-wrapped parts of the geogrid failure,the connection between the anti-wrapped geogrid and the upper geogrid should be strengthened, and enough buried length in the sand should be guaranteed.In addition, in order to avoid the tunneling of wrapped parts, a layer of anti-filter geotextile should be laid between the sand filling layer of retaining wall and the anti-wrapped geogrid.%为了给反裹式加筋砂挡墙设计与施工提供依据,分别用铁丝窗纱和纤维窗纱加筋的反裹式加筋砂挡墙进行土工离心模型试验,对比分析了墙顶沉降与墙面水平位移、墙内土压力和筋材应变随离心加速度增加的变化规律.试验结果表明:2种加筋材料的反裹式加筋砂挡墙模型具有良好的整体稳定性.当反裹式加筋砂挡墙出现不均匀沉降和外鼓变形时,土工格栅会发挥明显的加筋作用.选择模量较高、抗变形能力较强的土工格栅,可有效地降低挡墙沉降和水平位移变形,以保证反裹式加筋上挡墙顶部的路面结构不会因填砂路基的沉降和水平位移过大而出现失稳开裂破坏.同时,应加强反裹土工格栅与上层土工格栅的连接,并保证在填砂内有足够的埋设长度,避免反裹部位的土工格栅失效.在挡墙墙面填砂与反裹土工格栅之间铺设一层反滤土工布,避免反裹部位淘空.