【摘要】 为了探究和平公路隧道衬砌结构发生开裂的原因及特征,自行研制了适用于该研究的隧道结构性能测试平台。试验平台由控制系统、供压系统和加载系统组成,能够实现对隧道模型任意位置的精确加载,可研究隧道结构在多种形式外荷载作用下的力学性能。基于该试验平台,以和平公路隧道二次衬砌为原型,根据其现场测试结果进行了几何相似比为10的物理模型试验,详细分析了隧道结构在试验过程中的变形规律和破坏特征。将模型试验结果与现场裂缝分布特征进行对比以验证试验结果的可靠性,并根据试验结果对隧道原型的工作状态进行评估。研究结果表明:在依据现场实测确定的偏压加载工况下,隧道结构整体呈压扁趋势,最大径向位移位于拱顶右侧;结构的受力变形过程可分为3个阶段,分别以拱顶开裂和仰拱开裂为分界点;拱顶内表面和拱脚外表面被拉裂,边墙内表面由于局部压应力过大也产生开裂;拱顶最先开裂且开裂情况最为严重,偏压一侧边墙较另一侧边墙严重;随着外荷载的增加,拱部开裂状况加剧,最终形成主开裂区并引起结构整体的失稳破坏;模型试验结果与隧道现场裂缝分布特征基本吻合;隧道原型研究断面目前虽处于安全状态,但应及时采取有效的处治措施,防止衬砌裂缝的进一步发展和结构的失稳破坏。更多还原

【Abstract】 A test platform to explore the reasons and characteristics of the lining structure cracking of a highway tunnel is proposed here. The test platform consists of a control system, driving system, and loading system that can precisely apply loads on any positions of the tunnel model to study the mechanical performance of the tunnel structure under various loading cases. Relying on the test platform and using the secondary lining of a highway tunnel in service as the prototype, a model test with a geometric similarity ratio of 10 was conducted based on the field measurements. The deformation laws and failure characteristics of the tunnel structure during the test process were studied in detail. The test results were compared with the characteristics of in-situ lining cracks to validate the test reliability, and the working state of the tunnel prototype was assessed based the test results. The test results show a squashed deformation trend of the tunnel structure under the asymmetrical loading case determined by field measurements, and the maximum radial displacement occurs on the right side of the vault. The deformation and cracking process of the tunnel lining can be divided into three phases with two dividing points of the vault cracking and inverted arch cracking. The cracking occurs on the inside surface of the vault and the outside surface of the arch foot by overtension, and the cracking on the inside surface of the sidewall is due to the high localized compression. The vault cracks firstly and its cracking state is the most serious. The right sidewall, bearing larger loads, cracks more seriously than the left one. With the increase in the applied load, the cracking state of the vault is further deteriorated and the primary cracking zone is formed there, causing the entire structure to lose its bearing capacity. The results of the model test agree with the distribution characteristics in-situ lining cracks. Although the studied section of the tunnel prototype is currently safe for use, effective treatment measures should still be adopted to prevent further development of the lining cracks and instability failure of the entire structure.更多还原