铁路隧道所受作用形式多样,其概率和分布情况差别很大,之前铁路隧道设计者在考虑多种作用对隧道结构的影响时,是将作用效应进行组合,在总效应上乘以调整系数反应结构内力的标准值,此种设计理念偏于保守且不利于反应不同作用的出现概率和对隧道结构的影响程度;本次研究将组合系数与各可变作用一一对应,形成相应的作用组合表达式,通过经验类比和校准的方法得出相应的组合系数,并以组合后的作用按荷载-结构模型对隧道结构进行加载,直接计算得出结构内力的设计值,更好的反应了不同作用产生的效应在隧道结构内力中的比重,有效找到最不利组合下的极限状态,安全性、经济性和适用性得到提高.%Railway tunnels are subject to various actions with disparity in probability and distribution.In the past,the designers of railway tunnel combined the effects of actions with total effect being multiplied by an adjustment factor to reflect the standard value of the internal force of the tunnel structure,when they considered the impacts of different actions on the railway tunnel structure.This design idea was conservative and can hardly reflect the occurrence probability of different actions and their impacts on the tunnel structure.In this paper,corresponding relationship between the combination coefficients and the variable actions was established to form corresponding expression for combination of actions.Corresponding coefficients for combination of actions were obtained by experience analogy and calibration.The combined actions were applied on the tunnel structure using load-structure model to calculate the design value of the structural internal force.The proposed method could reflect the proportion of the effects of different actions in the internal force of the tunnel structure and by this method,the limit state would be effectively found under the most unfavorable combination of actions,which will help increase the safety,economy and applicability of the tunnel structure.
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