超前小导管注浆等效模拟及参数设计研究

发布时间：2018-04-22 17:38

本文选题：超前小导管注浆 + FLAC3D　；参考：《华南理工大学》2015年硕士论文

【摘要】：浅埋暗挖法施工时,软弱围岩因其强度低、抗扰动能力差,通常需要在开挖前对掌子面上方岩层进行超前支护,而超前小导管注浆具有操作简便、造价较低、防水加固效果好等优势,是适用性较广的一种方法。但目前超前小导管注浆的参数设计主要以施工经验为主,对其作用机理、模拟参数的等效计算等方面研究尚不明确和深入。针对目前超前小导管注浆研究中存在的不足,本文从超前小导管注浆的加固作用机理、Flac3D模拟超前小导管和注浆加固圈、超前小导管注浆的施工参数设计四个方面进行研究,重点对Flac3D模拟超前小导管和注浆加固圈的作用机理、各参数对围岩沉降的影响两个方面进行了研究,得出的结论如下:(1)当外插角15o时,建议采用Beam单元模拟小导管,外插角15o时,建议采用Cable单元模拟。Beam导管群的Fx最大,且呈对称分布,是Fy、Fz的102左右,弯矩Mx很小,可忽略不计;Fy与Fz、My与Mz的值相差不大,且最大值均发生在隧道的拱腰部位;Cable单元的轴向应力和水泥浆应力均呈对称分布,且受力较均匀。(2)Beam单元模拟导管时,除了其长度,其余参数均与围岩沉降差值呈正比关系,其影响由大到小依次为:外插角度、导管间距、导管直径;Cable单元模拟时,各参数影响由大到小依次为:导管布置范围、外插角度、导管长度、布置间距、导管直径。(3)等效加固圈的E、c、φ、t值与围岩沉降差值呈正比关系,其中,E的增长在c、φ提高的前提下,对围岩沉降的控制明显;c、φ的提高都有其上限值,分别为0.2MPa和45o;泊松比的变化对围岩沉降的影响不大,可以忽略。(4)对沉降差值与小导管、加固圈各参数的关系公式进行隧道的跨度和埋深修正,将各关系公式通过C语言编入程序,该程序可根据用户输入需要控制的沉降差值?z,求出相关的超前支护设计参数,计算应用方便快捷。将本文的研究成果应用于实际工程,验证了应用程序的可靠性,可为超前小导管注浆的各参数的设计及施工方案的确定提供参考和设计依据。
[Abstract]:In shallow underground excavation construction, the weak surrounding rock usually needs to support the rock layer above the face before excavation because of its low strength and poor anti-disturbance ability, but the grouting of the leading small pipe is easy to operate, and the cost is relatively low. Waterproofing and reinforcement effect is good and so on, it is a method of wide applicability. However, at present, the design of grouting parameters of leading small ducts is mainly based on construction experience, so the research on its action mechanism and equivalent calculation of simulation parameters is not clear and thorough. In view of the shortcomings of the present research on the advance small pipe grouting, this paper studies the reinforcement mechanism of the leading small pipe grouting from four aspects: the Flac3D simulation of the leading small pipe and the grouting reinforcement ring, and the design of the construction parameters of the leading small pipe grouting. This paper focuses on the mechanism of Flac3D simulation leading small ducts and grouting reinforcement rings, and the influence of each parameter on the settlement of surrounding rock. The conclusions are as follows: 1) when the extrapolation angle is 15o, it is suggested that the Beam element be used to simulate the small ducts. When the extrapolation angle is 15o, it is suggested that the Cable element be used to simulate the maximum FX of the .beam catheter group, which is about 102 of the FY Fz, and the bending moment Mx is very small, so the difference between Fy and FZM y and Mz is negligible. The maximum values occur in both axial stress and cement slurry stress of cable element at the arch waist of tunnel, and when the stress is more uniform, except its length, the other parameters are proportional to the difference value of surrounding rock settlement. The order of influence from large to small is as follows: extrapolation angle, catheter spacing, conduit diameter cable element simulation, the influence of each parameter from big to small is as follows: conduit layout range, extrapolation angle, duct length, arrangement spacing, The diameter of ducts. 3) the value of E, 蠁 t is proportional to the difference value of surrounding rock settlement, and the increase of E is in the premise of the increase of c and 蠁, the control of the settlement of surrounding rock is obvious c, and the increase of 蠁 has its upper limit value. The variation of Poisson's ratio has little effect on the settlement of surrounding rock, and can be ignored. Each relation formula is programmed by C language. The program can calculate the relative design parameters of advance support according to the difference value of settlement which needs to be controlled by the user, and it is convenient and quick to calculate and apply. The research results of this paper are applied to practical engineering, and the reliability of the application program is verified, which can provide a reference and design basis for the design of the parameters and the determination of the construction scheme of the leading small pipe grouting.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.4

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