考虑蠕变效应的软土地基加筋土挡墙变形

Deformation of Reinforced Soil Retaining Wall on Soft Soil Ground Considering Creep Effects

为探讨加筋土挡墙结构与软土地基共同作用下的长期性能,通过室内蠕变试验研究了土工格栅和软土的蠕变特性,并结合试验所得的蠕变参数建立了考虑蠕变效应的本构模型,在此基础上采用有限元法对一座软土地基上的土工格栅加筋土挡墙实例工程的工作特性进行了分析,研究了考虑加筋材料蠕变的加筋土挡墙长期变形特性.结果表明:文中所建立的数值模型可以较好地模拟软土地基上加筋土挡墙的长期蠕变力学行为;加筋土挡墙侧向位移随时间延长而逐渐增大,侧向位移沿挡土墙墙高分布呈现中部变形大、两端变形小的特征;最大侧向位移的位置随时间而沿墙高上升;受地基变形的影响,各加筋层的最大拉力和最大应变发生位置与目前土工合成材料加筋土挡墙设计理论认为的朗肯破坏面位置不同.文中还通过数值分析得到了不同时间下土工格栅拉力与应变沿墙高的分布规律,为软土地基上加筋土挡墙的设计提供了参考.

In order to explore the long-term performance of the geogrid-reinforced soil retaining walls and the soft soil ground under combined action, the creep properties of the geogrid and the soft soil were investigated through creep tests, and a constitutive model considering the creep effect was established based on experimental results. Then, a case study on a geogrid-reinforced soil retaining wall built on soft soil ground was performed by using the finite element method, and the long-term deformation performance of the wall considering the creep effect of rein- forcement material was analyzed. The results show that （ 1 ） the proposed numerical model is effective in simulating the long-term creep behaviors of the reinforced soil retaining wall on soft soil ground; （2） the lateral displacement of the reinforced wall gradually increases with time and becomes larger at the central part but smaller at the two ends of the wall ; （3） with the prolonging of time, the position of maximum lateral displacement along the wall becomes higher; and （4） due to the influence of foundation deformation, the positions of maximum tension and strain of each geogrid layer are different from the Rankine failure surface stated by the current design theory. In addition, the distribution law of geogrid tension and strain along the wall at different times, which is obtained by numerical simulation, provides some references for the design of reinforced soil retaining walls on soft soil ground.