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本文采用地质定性分析和FLAC3D三维数值模拟定量分析的方法,以保定市王快水库和西大洋水库综合管理工程中的湾子隧洞为例,分析研究了第三系泥岩中浅埋水工隧洞的变形特征及存在的主要工程地质问题。研究结果表明,极软岩隧洞变形的主要形式为底鼓、边墙内移和拱顶下沉。初期支护底板不封闭时,泥岩隧洞变形最初体现为底鼓,然后为底脚内移及拱顶下沉。软弱夹层、张性裂隙、地下水等不良地质因素,以及底板初期支护滞后等施工因素,对泥岩隧洞稳定性存在明显的不利影响,极易引起拱顶塌方、片帮甚至整体失稳等不良地质问题。故极软岩隧洞初期支护应紧跟掌子面,并及时进行永久衬砌。
In this paper, the geological qualitative analysis and FLAC3D three-dimensional numerical simulation quantitative analysis methods to Baotou Wang Kuai Reservoir and West Ocean Reservoir Integrated Management Project of the Bayi tunnel as an example, analysis of the Tertiary mudstone shallow buried tunnel Deformation characteristics and the existence of the main engineering geological problems. The results show that the main deformation of the extremely soft rock tunnel is the bottom drum, the displacement of the side wall and the vault sinking. When the initial supporting floor is not closed, the deformation of the mudstone tunnel initially manifests as the bottom drum, then the bottom foot moves inwards and the vault sinks. Weak interbeds, zonal fractures, groundwater and other unfavorable geologic factors, as well as the initial support of the floor lagging and other construction factors have obvious adverse effects on the stability of mudstone tunnels, can easily lead to vault collapse, sheeting or even the overall instability and other adverse geological problem. Therefore, very soft rock tunnel initial support should be followed by the palm face, and timely for a permanent lining.