降水对桥基影响的三维渗流-应力耦合分析

THREE-DIMENSIONAL SEEPAGE-STRESS COUPLING ANALYSIS OF BRIDGE FOUNDATION BEHAVIORS INDUCED BY PRECIPITATION

近邻桥梁进行降水施工时,地层的固结变形导致桥梁基础变形,当桥梁的基础变形过过大时,可能危及桥梁的安全和正常运行。为了预测降水过程中桥梁基础的空间响应和评估其安全状态,建立三维非饱和渗流–应力耦合分析数学模型,同时,运用ABAQUS软件,建立地层、地下水、桥梁相互作用的三维有限元模型。采用直接耦合分析方法,对近邻桥基进行降水施工时的动态降水过程进行三维仿真模拟。模拟结果表明,水位下降10m时,降水所引起的地表最大沉降值为21.37mm,桥基的最大沉降值为19.56mm,相邻桥基的差异沉降不到2mm,表明降水期间桥基没有安全隐患,现有的降水方案是可行的。通过将沉降计算值与现场量测值比较分析,两者数据吻合较好,表明所提出的计算模型和分析方法是合理的,可为类似问题的研究提供了借鉴和参考。

The safety of the bridge and its normal operation are possibly influenced when the deformation of bridge foundation is largely induced by ground consolidation and the groundwater table in the stratum under the bridge foundation is lowered. In order to predict safety and deformation of bridge foundations during precipitation, 3D non-saturation seepage-stress coupling theoretical analysis model is set up; and the 3D FEM model of interaction of ground, groundwater and bridge is also set up by software ABAQUS. Based on the direct coupling analysis method, spatial responses of bridge foundations during precipitation and the dynamic changes of groundwater table are simulated. It is discovered that ground settlement is 21.37 mm and bridge foundation settlement is 19.56 mm; and differential settlement between bridge foundations is less than 2 mm under the condition of descending 10 m water table. It is also proven that the bridge foundation is safe and the existing precipitation scheme is reasonable. The simulated and measured settlement values agree well. So it is demonstrated that numerical model and analysis method are reasonable and reliable, and it can offered important guidance and reference to the study of similar problem.