温度-围压作用下盾构隧道衬砌应力变化规律研究

为分析围岩压力和温度变化对盾构隧道衬砌应力变化的影响。文中推导了衬砌应力计算公式,并利用所得公式采用MATLAB绘制了衬砌应力变化图,对衬砌应力变化规律进行了理论分析。结果表明,①衬砌各方向应力随围岩压力的增大而线性增加;②径向与环向应力随内外壁温差增加,压应力逐渐减小到0 kPa后转变为拉应力并逐渐增大,纵向应力基本不随温差而发生改变;③当温差为正时,径向拉应力和纵向压应力逐渐减小,环向压应力减小到0 kPa后转变为拉应力逐渐增大,当温差为负时,径向压应力减小,环向和纵向压应力随半径增加而变大。分析得到的衬砌应力变化规律可为隧道支护结构设计提供参考。

Research on Stress Variation Law of Shield Tunnel Lining under Temperature and Confined Pressure

In order to analyze the influence of surrounding rock pressure and temperature changes on the stress variation of shield tunnel lining,the formulas for calculating the stress of lining are deduced,and the stress variation diagram of lining is drawn with MATLAB.The stress variation law of lining is also theoretically analyzed.The results show that:①The compressive stress of the lining in all directions is increased linearly with the increase of surrounding rock pressure;②As the temperature difference between the inner and outer walls of lining increases,the radial and circumferential compressive stress gradually decreases to zero,then changes to tensile stress and increases gradually,and the longitudinal stress does not change substantially with the temperature difference;③With the increase of the segment radius:when the temperature difference between the inner and outer walls of lining is positive,the radial tensile stress and longitudinal compressive stress decrease gradually,the circumferential compressive stress decreases to zero,and then changes to tensile stress and increasesgradually;when the temperature difference is negative,the radial compressive stress decreases,and the circumferential and longitudinal compressive stress increases.The analysis results can provide reference for the design of tunnel support structure.