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新建隧道下穿既有桥梁基础,特别是浅埋桥基时会对其产生不利影响,将尖点突变理论引入隧道下穿施工影响下浅埋桥基的稳定性评价,根据浅埋桥基系统失稳特点确定尖点突变模型的控制变量和状态变量,由尖点突变势函数推导出桥基结构的行为曲面方程,建立描述隧道下穿施工影响下浅埋桥基失稳的数学模型;然后根据该模型将桥基稳定性状态分为稳定阶段、不稳定阶段和失稳破坏阶段,并将各阶段的划分界限严格量化,作为结构的失稳判据;最后将此方法应用于某工程实例,分析结果和工程监测结果的对比表明该方法具有良好的分辨能力与准确性,为开挖施工影响下的浅埋桥基稳定性评价提供了一条新的思路与方法。
The new tunnel underlies the existing bridge foundation, especially when the bridge foundation is shallow, it will have an adverse effect on it. The cusp catastrophe theory is introduced into the stability evaluation of shallow buried bridge foundation under the tunnel under-crossing construction. According to the shallow buried bridge foundation system Instability characteristics of the cusp catastrophe model to determine the control variables and state variables cusp catastrophe potential function derived from the behavior of the bridge surface structure of the equation to establish a mathematical model describing the stability of shallow underburden under the tunnel under the influence of construction; According to this model, the stability status of the bridge foundation is divided into the stable phase, the unstable phase and the steady-state failure phase, and the boundary of each phase is strictly quantified as the instability criterion of the structure. Finally, this method is applied to an engineering example The comparison between the analysis results and engineering monitoring results shows that the method has good resolving power and accuracy and provides a new idea and method for the stability evaluation of shallow abutment under the influence of excavation.