考虑施工特性的浅埋软弱洞口段管棚变形量预测及工程应用

发布时间：2018-02-26 06:12

本文关键词： 隧道工程软弱围岩施工特性变形预测工程应用　出处：《岩石力学与工程学报》2017年03期 　论文类型：期刊论文

【摘要】：针对洞口管棚受开挖过程影响的特点,考虑初期支护延滞性、围岩应力释放差异性、地层反力系数不均匀性和仰坡坡度等因素,将管棚划分为初支闭合段、初支未闭合段、开挖未支护段、掌子面前方塑性扰动段、弹性扰动段和无扰动段,建立基于Pasternak弹性地基梁理论并考虑施工特性的洞口管棚变形量预测模型。利用有限单元法思想和梁段纵向剪力传递理论,获得管棚变形预测理论值,并应用于桦皮岭隧道工程。结果表明:(1)Pasternak力学模型摈弃了Winkler弹性地基梁不能传递纵向剪力的缺陷,其预测值与现场试验结果吻合度较高,最大偏差较Winkler模型减小11.8%,更适合洞口管棚变形预测。(2)管棚变形量随地层反力系数和管棚直径增大而减小,但非线性关系;管棚环向间距与变形呈正比例关系;当地层反力系数和管棚直径超过某一数值,通过调整注浆改善地层反力系数或直径方法来控制管棚变形效果甚微。(3)在给定变形控制基准下,确定IV,V和VI级围岩不同纵坡条件下经济合理的管棚直径和环向间距,并制定了管棚设计施工参数选择一览表。其研究成果为完善管棚计算方法、设计施工体系提供参考和借鉴。
[Abstract]:In view of the characteristics of pipe shed affected by excavation process, considering the factors such as the initial support delay, the difference of surrounding rock stress release, the non-uniformity of the formation reaction coefficient and the slope of the upside-slope, the pipe shed is divided into the initial branch closed section and the initial branch unclosed section. Excavated unsupported section, plastic disturbance section in front of face, elastic disturbance section and undisturbed section, Based on the Pasternak elastic foundation beam theory and considering the construction characteristics, the deformation prediction model of pipe shed is established. The theoretical value of pipe shed deformation prediction is obtained by using the finite element method and the longitudinal shear transfer theory of beam section. The results show that the Winkler elastic foundation beam can not transfer longitudinal shear force, and the predicted value is in good agreement with the field test results. The maximum deviation is 11. 8% smaller than the Winkler model, which is more suitable for the deformation prediction of the tube shed at the hole. 2) the deformation of the pipe shed increases with the increase of the resistance coefficient and the diameter of the pipe shed, but it is nonlinear, and the circumferential distance of the pipe shed is proportional to the deformation. If the local layer reaction coefficient and the pipe shed diameter exceed a certain value, the deformation of the pipe shed can be controlled by adjusting the grouting method to improve the formation reaction coefficient or diameter. This paper determines the economical and reasonable pipe shed diameter and circumferential spacing under different longitudinal slope conditions of IVV and VI surrounding rocks, and formulates a list of the design and construction parameters of the pipe shed. The research results provide reference for perfecting the calculation method of pipe shed and design and construction system.
【作者单位】：西南交通大学土木工程学院;河北交通职业技术学院土木工程系;石家庄铁道大学土木工程学院;中铁十一局集团有限公司;
【基金】：国家自然科学基金资助项目(51478277) 河北省高等学校科学技术研究重点项目(ZD2015096) 河北省高等学校科学技术研究青年基金项目(QN2014161)~~
【分类号】：U456.3

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