库水位抬升对软岩隧道锚长期稳定性影响研究

发布时间：2018-02-23 05:29

本文关键词： 隧道锚原位模型试验软岩蠕变长期稳定性数值模拟　出处：《长江科学院》2015年硕士论文　论文类型：学位论文

【摘要】：拟建的几江长江大桥北岸拟采用隧道式锚碇,基岩为侏罗系上统遂宁组泥岩,局部夹砂岩,中等风化程度,属于典型的浅埋、软岩隧道锚,标准组合下单根主缆拉力1.08×105kN。同时北岸部分隧道锚体及围岩处于库水位下,下游小南海水电站建成运营后将进一步抬升库水位,而泥岩有遇水软化和受荷蠕变的特性,地下水及其水位将对隧道锚长期稳定性产生影响。国内外极少见到在浅埋、软岩、富水环境中修建高拉拔荷载的隧道式锚碇。因此深入研究复杂环境下锚碇长期稳定性,评价其可行性,进一步拓展隧道锚适用范围,对我国公路交通建设具有十分重要的意义。本文以几江长江大桥北岸隧道式锚碇方案为研究背景,率先设计并实施泡水和天然状态下的隧道锚缩尺模型恒载张拉对比试验,揭示锚碇-围岩系统时效变形特性及地下水的影响作用;同时依据室内外岩石力学试验、模型试验测试结果,利用PSO-LSSVM反演分析方法辨识得到天然和富水泥岩在拉拔荷载下蠕变模型、蠕变参数;在此基础上开展了实桥锚碇-围岩系统的三维数值分析,研究了锚碇长期稳定性以及库水小幅抬升影响作用,结果表明,库水小幅抬升后,泥岩受到水的影响而弱化,锚碇-围岩系统的蠕变位移比库水抬升前有所增大,但幅度不大,锚碇体周边围岩基本处于弹性工作状态,仅锚碇前、后端面附近出现小范围的塑性区。
[Abstract]:In the north bank of the proposed Yangtze River Bridge, tunnel Anchorage is to be adopted. The bedrock is mudstone of Suining formation of Jurassic Upper Series, partial intercalation of sandstone, medium weathering degree, belonging to typical shallow buried, soft rock tunnel anchor. The standard combination issued an order root cable tension of 1.08 脳 105 kN. at the same time, some tunnel anchors and surrounding rocks in the north shore are under the reservoir water level, the downstream Xiaonanhai Hydropower Station will further raise the reservoir water level after completion and operation, while the mudstone has the characteristics of water softening and loading creep. Underground water and its water level will affect the long-term stability of tunnel anchors. It is seldom seen at home and abroad to build tunnel anchorages with high pull-out loads in shallow buried, soft rock and water-rich environments. Therefore, the long-term stability of anchorages in complex environments is deeply studied. It is of great significance to evaluate its feasibility and further expand the applicable range of tunnel anchors for highway traffic construction in China. This paper takes the tunnel Anchorage scheme on the north bank of Jijiang and Yangtze River Bridge as the research background. In order to reveal the aging deformation characteristics of Anchorage surrounding rock system and the influence of groundwater, the comparative test of tunnel anchor scale model under the condition of bubble water and natural state is first designed and carried out in order to reveal the influence of underground water on the aging deformation of Anchorage surrounding rock system, and according to the indoor and outdoor rock mechanics tests, The creep model and creep parameters of natural and cement-rich rock under pull-out load were identified by using PSO-LSSVM inversion analysis method, and the three-dimensional numerical analysis of solid bridge anchorage-surrounding rock system was carried out. The long-term stability of Anchorage and the effect of small uplift of reservoir water are studied. The results show that the mudstone is weakened by water after small uplift, and the creep displacement of Anchorage surrounding rock system is larger than that before water uplift, but the range is not large. The surrounding rock around the Anchorage is basically in an elastic state, and a small area of plastic zone appears near the front of the Anchorage and the rear end face.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.24;U448.25

【参考文献】