高速铁路隧道二次衬砌的变形特性与极限承载能力

发布时间：2018-10-08 21:18

【摘要】：通过分析《铁路隧道设计规范》中二次衬砌结构与普通受压结构在边界条件、平衡方程上存在的差别,认为采用单轴抗拉、抗压强度作为判断高速铁路隧道二次衬砌材料破坏的参数过于安全。以Ⅴ级围岩、350km·h~(-1)速度的高速铁路隧道为对象,运用MIDAS—NX数值模拟软件建立拟地层—结构模型,推导摩尔库伦强度准则下混凝材料强度参数与单轴强度的换算关系,在此基础上分析二次衬砌的变形特性与极限承载能力,并与二次衬砌受力实测数据比对。研究结果表明:在临界破坏状态下,随着侧压力系数的逐渐增大,洞形由扁平逐渐变到直立;二次衬砌结构受载后,内外侧塑性区的变化受侧压力系数的影响明显;在侧压力系数为1.4时,二次衬砌的承载效果最佳;二次衬砌中的钢筋主要控制衬砌单元的第一主应力(拉应力);二次衬砌的实际受载量远小于其极限承载能力,因此可对二次衬砌进行"减薄"。
[Abstract]:By analyzing the difference in boundary conditions and equilibrium equations between the secondary lining structure and the common compression structure in the Code for Railway Tunnel Design, it is considered that uniaxial tensile resistance is used. The compressive strength is too safe to judge the secondary lining material failure of high speed railway tunnel. Taking the high-speed railway tunnel with 350 km h-1 velocity of grade V surrounding rock as an object, the pseudo-stratigraphic structure model is established by using MIDAS-NX numerical simulation software, and the conversion relationship between strength parameters and uniaxial strength of coagulant material under the Moore Coulomb strength criterion is deduced. On this basis, the deformation characteristics and ultimate bearing capacity of the secondary lining are analyzed, and compared with the measured data of the secondary lining. The results show that under the critical failure condition, with the increasing of the lateral pressure coefficient, the cavity shape gradually changes from flat to upright, and the lateral pressure coefficient affects the plastic zone of the inner and outer side obviously after the secondary lining structure is loaded. When the lateral pressure coefficient is 1.4, the bearing capacity of the secondary lining is the best, the reinforcement in the secondary lining mainly controls the first principal stress (tensile stress) of the lining unit, and the actual loading capacity of the secondary lining is far less than its ultimate bearing capacity. Therefore, the secondary lining can be "thinned".
【作者单位】：北京交通大学城市地下工程教育部重点实验室;北京城建集团有限责任公司;苏交科集团股份有限公司;
【基金】：国家自然科学基金重点项目资助(U1234210) 中交路桥华北工程有限公司科技攻关项目(1401027)
【分类号】：U455.91

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