预切槽法开挖隧道地层变形及预筑拱受力试验

发布时间：2018-04-24 21:49

本文选题：隧道工程 + 预筑拱　；参考：《中国公路学报》2017年07期

【摘要】：为了明确预切槽法开挖隧道过程地层和预筑拱的力学响应,设计了1∶10大比尺三维地质力学模型试验,真实地模拟了预切槽法的切槽灌注和掌子面土体开挖过程,研究了预切槽法施工过程中地层变形及预筑拱结构受力情况。通过土体中埋设的位移、土压力及应变测点得到了洞周土压力和预筑拱的应变值,通过对试验数据的分析和与数值模型计算的对比,进一步了解地层变形的发展过程,寻找结构受力特征及施工过程的关键问题。研究结果表明:切槽混凝土灌注压力和灌注及时性对预筑拱成拱效果的影响较大;切槽及灌注混凝土过程引起的地层沉降占比较大,预筑拱形成后下部土体开挖引起的地层沉降较小,说明预筑拱可以保护掌子面超前核心土,显著减少隧道收敛变形,有效控制地层沉降;预筑拱两侧边墙和拱腰受压,拱顶主要受拉,采用素混凝土灌注的预筑拱极易发生破坏,实际工程设计施工时需要注意提高预筑拱抗拉性能。
[Abstract]:In order to make clear the mechanical response of stratum and arch during tunnel excavation by pre-cutting method, a three dimensional geomechanical model test of 1:10 large scale was designed, and the process of slotting pouring and excavation of soil on the palm surface of pre-cutting method was simulated. The deformation of stratum and the stress of pre-arch structure during the construction of pre-cutting groove method are studied. The soil pressure around the hole and the strain value of the pre-built arch are obtained by the displacement, earth pressure and strain measurement points embedded in the soil. The development process of the formation deformation is further understood through the analysis of the test data and the comparison with the numerical model calculation. To find the key problems of structural stress characteristics and construction process. The results show that the influence of grouting pressure and timeliness on the effect of arch formation is great, and the formation settlement caused by the process of cutting and pouring concrete accounts for a great deal. The ground settlement caused by soil excavation in the lower part of the pre-arch is small, which shows that pre-arch can protect the core soil ahead of the palm surface, reduce the convergent deformation of the tunnel, control the ground settlement effectively, and pre-build the side wall and waist of the arch under pressure. The arch roof is mainly subjected to tension, and the pre-construction arch with plain concrete pouring is easy to be destroyed. In actual engineering design and construction, attention should be paid to improving the tensile performance of pre-built arch.
【作者单位】：北京交通大学隧道及地下工程教育部工程研究中心;北京市政工程研究院;
【基金】：国家自然科学基金项目(51178026) 北京交通大学研究生创新基金项目(2016YJS092)
【分类号】：U456

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