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为准确预测高速铁路沉降量,严格控制高速铁路沉降,达到高速铁路的平顺性标准,以某一软土地基高速铁路桥梁墩台为监测对象,采用液位-单点联合自动监测法对天津某特大桥沉降进行了长期观测。实测数据分析显示,单点沉降计布置合理的情况下能准确确定压缩层厚度。与现有规范的压缩层及沉降进行对比分析,结果表明,《公路桥涵地基与基础设计规范》误差最大,压缩层厚度比实测值大141.1%,沉降量比实测值大182.9%;按上海市《地基基础设计规范》得到的沉降量计算值比实测值大4.0%;按《建筑桩基技术规范》得到的应力比为10%,沉降量计算值比实测值大8.9%。与液位沉降计测得的总沉降相比,《铁路桥涵地基和基础设计规范》、《公路桥涵地基与基础设计规范》计算的沉降值偏大,其余规范计算的沉降值均偏小。从可靠性和安全角度考虑,建议采用以10%应力比为条件的“应力控制法”计算压缩层厚度,采用铁路规范方法计算高速铁路深厚松软土层的桥梁桩基总沉降。
In order to accurately predict the settlement of high-speed railway, the settlement of high-speed railway is strictly controlled and the ride comfort standards of high-speed railway are met. Taking the abutment of high-speed railway bridge on a soft soil foundation as monitoring object, Long-term observation of the bridge subsidence. The measured data analysis shows that the single-point settlement meter can accurately determine the thickness of the compressed layer when the layout is reasonable. Compared with the existing compression layer and settlement, the results show that “the error of foundation and foundation design code for highway bridge and culvert is the largest, the thickness of compression layer is 141.1% larger than the measured value and the settlement is 182.9% larger than the measured value. According to the data of Shanghai The calculated value of subsidence calculated by Foundation Design Code is 4.0% larger than the measured value. The calculated stress ratio is 10% according to Technical Specifications of Pile Foundation, and the calculated settlement value is 8.9% larger than the measured value. Compared with the total subsidence measured by the liquid level subsidence gauge, the subsidence values calculated according to ”Code for foundation and foundation design of railway bridges and culverts“ and ”Code for foundation and foundation design of highway bridges and culverts“ are large, and the subsidence values calculated by the other codes are all small. From reliability and safety point of view, it is recommended to calculate the compressive layer thickness by ”stress control method " under the condition of 10% stress ratio and calculate the total settlement of bridge pile foundation in deep and soft high-speed railway by using railway code method.