地基土类型对加筋土桥台承载性能的影响研究

Study on the influence of foundation soil type on the bearing characteristic of geosynthetic reinforced soil abutment

为研究地基土类型对土工合成材料加筋土(GRS)桥台承载性能的影响,设计并完成了砂土地基和软土地基上的GRS桥台两组室内模型载荷试验.以石英砂和高岭土模拟两种不同类型的地基土,通过对模型分级加载研究加筋土桥台在两种地基上的承载性能,对比分析GRS桥台在两种地基上的变形受力特征及破坏规律.试验结果表明:砂土地基组GRS桥台在上部荷载作用下变形较小,墙面位移随着荷载的增大呈鼓肚状,软土地基组桥台受到较小荷载时达到破坏,桥台加筋区整体下陷,墙面位移随高度的降低逐渐增大,桥台破坏形式为整体失稳破坏;地基土类型对竖向土压力增量的影响较小,试验测得的竖向土压力增量结果与美国联邦公路局的计算方法比较符合;软土地基在竖向荷载作用下发生较大变形,同一高度处筋材在软土地基中应变值更大.

To study the influence of foundation soil type on the bearing characteristic of geosynthetic reinforced soil(GRS)abutment,two GRS abutment load tests on sand foundation and soft soil foundation were designed and completed.Quartz sand and kaolin were used to simulate two different types of foundation soils,and the bearing performance of GRS abutments on the two foundations was studied through the graded loading.Deformation,stress characteristics and failure laws on two types of foundations were compared and analysed.The test results showed that the GRS abutment on the sand foundation has little deformation when it is loaded,and the wall displacement is similar to bulging with the increase of the load.The abutment on the soft foundation reaches failure when subjected to a small load,the reinforced area of the abutment sinks as a whole when the abutment is damaged,and the wall displacement gradually increases with the decrease in height,the abutment failure is in the form of overall instability failure.The type of foundation soil has little effect on the incremental vertical stress,measured incremental vertical soil stress is more consistent with the FHWA method.Due to the large deformation of soft soil foundation under vertical load,the strain value of the reinforcement at the same height is larger on the soft soil foundation.