Xu Chao, Wang Qingming, Shen Panpan, Li Geye, Wang Qiushen, Zhang Xiao, Zhao Chongxi
Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China.
Shanghai Investigation, Design & Research Institute Co., Ltd., Shanghai 200434, China.
Materials (Basel). 2023 Jun 26;16(13):4601. doi: 10.3390/ma16134601.
This study conducted plane-strain scaled model tests to investigate the deformation characteristics of geosynthetic reinforced soil (GRS) abutments subjected to vertical loads. Setback distance, i.e., the distance between the back of the abutment facing and the front of the loading plate, was chosen as the investigated influencing factor since it is one of the most frequently used variables by engineers for the design of GRS abutments. This study analyzed the settlements at the top of the abutment, the lateral displacements of the abutment facing, and the volumetric deformations of the abutment under the applied vertical loads. Test results showed that increasing the setback distance could effectively reduce the deformations of the GRS abutment. There existed an optimum setback distance and further increasing the setback distance beyond this optimum value did not have a significant effect on reducing the abutment deformations. The vertical, lateral, and total volumetric deformations of the GRS abutment showed an approximately linear increase with the increase of the applied vertical loads. The lateral volumetric deformations of the GRS abutment were larger than its vertical volumetric deformations and therefore the total volumetric strains of the GRS abutment were not zero based on the test results. However, the theory of zero volume change may still be suitable for the deformation calculation of the GRS abutment since the values of the volumetric strains were minimal. The measured maximum lateral facing displacements were compared with the calculated values using the US Federal Highway Administration (FHWA) method, which assumes zero volume change of the GRS abutment under vertical loads. Comparison results indicated that the FHWA method overestimated the maximum lateral facing displacements of the GRS abutment under vertical loads. An improved method was proposed in this study to calculate the maximum lateral facing displacements under vertical loads based on the theory of zero volume change and a revised distribution of the settlements at the top of the GRS abutment. Results showed that the improved method could better predict the maximum lateral facing displacements as compared to the FHWA method.
本研究进行了平面应变比例模型试验，以研究土工合成材料加筋土（GRS）桥台在垂直荷载作用下的变形特性。由于退台距离（即桥台正面背面与加载板前端之间的距离）是工程师在GRS桥台设计中最常用的变量之一，因此将其选为研究的影响因素。本研究分析了桥台顶部的沉降、桥台正面的侧向位移以及在施加垂直荷载下桥台的体积变形。试验结果表明，增加退台距离可有效减少GRS桥台的变形。存在一个最佳退台距离，超过此最佳值进一步增加退台距离对减少桥台变形没有显著影响。GRS桥台的垂直、侧向和总体积变形随施加的垂直荷载增加呈近似线性增加。GRS桥台的侧向体积变形大于其垂直体积变形，因此根据试验结果，GRS桥台的总体积应变不为零。然而，体积变化为零的理论可能仍适用于GRS桥台的变形计算，因为体积应变值很小。将实测的最大正面侧向位移与使用美国联邦公路管理局（FHWA）方法计算的值进行了比较，该方法假定GRS桥台在垂直荷载下体积变化为零。比较结果表明，FHWA方法高估了GRS桥台在垂直荷载下的最大正面侧向位移。本研究提出了一种改进方法，基于体积变化为零的理论和GRS桥台顶部沉降的修正分布来计算垂直荷载下的最大正面侧向位移。结果表明，与FHWA方法相比，改进方法能更好地预测最大正面侧向位移。
