考虑刀盘厚度隧道开挖面极限支护压力的计算

Solution of Ultimate Support Pressure on Tunnel Excavation Surface Considering Cutter Plate Thickness

针对目前盾构隧道开挖面支护压力的理论计算模型未考虑刀盘厚度的影响,从而导致计算结果偏小这一问题,在考虑刀盘厚度对开挖面支护压力影响的基础上,对现有的三维楔形体计算模型进行了改进。利用极限平衡分析法计算开挖面极限支护压力,并与数值模拟计算结果进行了对比验证。研究结果表明:当刀盘厚度大于0.5 m时,极限平衡分析法结果与数值模拟计算结果误差在20%以内,而传统理论模型计算结果与数值模拟计算结果误差超过40%。当隧道埋深大于15 m、隧道直径大于8 m时,由极限平衡分析法计算的结果和数值模拟计算的结果误差在10%以内,两结果吻合较好,证明本文在考虑刀盘厚度影响下所建立的三维楔形体计算模型,比传统理论计算模型更合理。

At present,the theoretical calculation model of shield tunnel excavation face support pressure ignored the effects of cutter plate thickness,which led to smaller calculation results.In order to solve this problem,this paper took the effect of cutter plate thickness on supporting pressure of excavation surface into account,and improved the calculation model on the basis of the existing wedge calculation model by using the limit equilibrium analytical method for a deep excavation face extreme pressure. The results show that when the thickness of cutter head is greater than 0. 5 m,the error between the result of limit equilibrium analytical method and the result of numerical calculation is within 20%,while the error between the result of traditional theoretical calculation model and the result of numerical simulation is over 40%.When the buried depth of the tunnel is greater than 15 m and the diameter of the tunnel is greater than 8 m,the error between the results calculated by the limit equilibrium analytical method and the results calculated by the numerical simulation is less than 10%. The two results are in good agreement,which proves that the three-dimensional wedge shape calculation model considering the influence of the thickness of the cutter plate is more reasonable than the traditional theoretical calculation model.