流变荷载作用下隧道二次衬砌损伤行为研究

Study on Damage Behaviors of Tunnel Secondary Lining under Rheological Load

  • 摘要: 软弱围岩的流变效应容易导致隧道二次衬砌开裂,影响结构的安全性和耐久性。因此,文章以广甘高速杜家山隧道为例,建立考虑Weibull损伤分布的混凝土数值计算模型,对流变荷载作用下二次衬砌的损伤演化行为进行了研究。结果表明:(1)若二次衬砌与围岩接触良好,衬砌损伤区域在侧压力系数λ为0.5,1,2时,分别分布在拱腰、拱脚以及拱顶与拱底附近;(2)空洞对衬砌损伤区域及其出现顺序都有较大影响,即损伤首先在空洞附近的混凝土中产生,且该位置处的混凝土均会产生较为严重的损伤;(3)地应力对存在空洞的二次衬砌损伤模式的影响可以分为两种,即影响损伤位置出现的先后顺序,但不影响结构最终损伤形态,或既影响损伤的出现顺序,又影响结构的最终损伤形态。

     

    Abstract: The rheological effect of soft and weak surrounding rocks can easily lead to the cracking of tunnel sec? ondary lining, affecting the safety and durability of the structure. In view of this, this paper takes the Dujiashan tunnel on Guangyuan-Gansu Expressway as an example and establishes a numerical calculation model based on Weibull damage distribution to investigate the damage evolution behaviors of the secondary lining under rheological load. The results show that: (1) if the secondary lining is in good contact with the surrounding rock, the lining cracking area is distributed near the arch waist, arch foot, as well as the top and bottom of the arch respectively when the lateral pressure coefficients are λ=0.5,1 and 2; (2) the cavity has a great impact on the lining cracking area and the order of the occurrence of the cracking, that is, the cracking is first induced in the concrete near the cavity, and the concrete at that specific location will all produce quite serious damage; and (3) the influence of the geostress on the damage patterns of the secondary lining with cavities can be divided into two kinds: the impact on the order of the occurrence of the damage location, but not on the final damage pattern of the structure, or the impact on both the order of the damage occurrence and the final damage pattern of the structure.

     

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