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铁路隧道一般位于山岭或水下的复杂地质环境中,面临着地下水的威胁,国内工程界对于管片衬砌所能承受的高水压一直没有明确的分界值。针对管片衬砌结构型式的特点,从接缝防水及结构受压承载能力两方面对高水压分界值展开研究。提出了管片衬砌结构高水压限界的定义及判定方法,求解了不同围岩级别、不同管片设计参数(混凝土强度等级、厚度)条件下的管片衬砌高水压承载能力。最后通过大比例尺模型试验对衬砌受水压作用的力学特征进行分析。研究结果表明:管片接缝在允许的张开量和错位量的前提下,同时考虑设计材料的应力松弛与老化,密封垫设计承受的最大水压能力约在0.8～1.0 MPa之间;管片环不同位置处的受压承载能力安全系数近似呈正弦曲线分布,拱顶及拱底位置为衬砌结构受力控制点,提高混凝土强度等级或加大管片厚度可以显著增加管片衬砌的受压承载能力;高水压条件下结构呈受压破坏,低水压条件下呈受拉破坏,一定范围内提升管片的外水压力,衬砌结构的轴力值增加明显,弯矩值变化幅度不大,对于结构受力是有利的。
Railway tunnels are generally located in the complex geological environment of mountains or underwater, facing the threat of groundwater. There is no clear boundary value for the high hydraulic pressure that the domestic engineering community can bear for the segment lining. Aiming at the characteristics of the type of segment lining structure, the study on the critical value of high hydraulic pressure from two aspects of the waterproofing of joints and the bearing capacity of the structure. The definition and determination method of high hydraulic pressure limit of segment lining structure are put forward. The high hydraulic bearing capacity of segment lining is obtained under different surrounding rock grades and different design parameters (concrete strength grade and thickness). Finally, the mechanical characteristics of lining subjected to water pressure are analyzed by large-scale model test. The results show that under the precondition of the allowable opening amount and dislocation amount, the stress relaxation and aging of the design material are taken into consideration. The maximum hydraulic capacity under seal design is about 0.8 ~ 1.0 MPa. The safety factor of compressive loading capacity at different positions is approximately sinusoidal and the position of vault and arch is the force control point of lining structure. Increasing the concrete strength grade or increasing the thickness of the slab can significantly increase the compressive load of the slab lining The structure under high hydraulic pressure is under the pressure failure, under the condition of low water pressure, it is under the tensile damage, and the external pressure of the pipe is increased within a certain range. The axial force value of the lining structure increases obviously and the variation of the bending moment value is not big , Which is beneficial to the structure.