深覆盖岩溶地基防渗墙渗透特性及承载性状分析

发布时间：2018-03-11 04:14

本文选题：混凝土防渗墙　切入点：水力耦合　出处：《南昌大学》2017年硕士论文　论文类型：学位论文

【摘要】：堤基防渗技术是在透水地基上修建挡水建筑物中的关键技术,它的成败关系到工程的安危。目前,深覆盖层岩溶地基采用混凝土防渗墙结合基岩帷幕灌浆的防渗方式,其综合防渗墙与帷幕灌浆的优点,能有效解决这类不良地质工程问题。然而,防渗墙深夹于坝体或覆盖层中,受力条件极其复杂,且属于隐蔽工程,合理评价防渗墙工作性能,对堤坝稳定运行尤为重要。鉴于防渗墙在水利工程中的广泛运用及堤坝防渗体系中的重要性,有必要对深覆盖层岩溶地基防渗墙的渗透特性及承载性状进行系统分析。在合理选择能考虑真实状态下土体本构及墙-土接触单元的基础上,本文基于流固耦合理论,依托峡江水利枢纽同赣堤防工程,运用ABAQUS及二次开发功能建立多孔介质材料的渗流场与应力场耦合分析的非线性数学模型,研究深覆盖层岩溶地基防渗墙应力变形及渗流性态。本文的具体研究工作如下:(1)简要概述控制堤基渗透变形的机理,提出防渗墙与帷幕灌浆联合防渗是解决深覆盖层岩溶复杂地基渗漏问题的主要措施。(2)介绍渗流、应力分析数学模型及基本微分方程的求解,在此基础上推导水力耦合相互作用机理及耦合方程的实现,同时运用ABAQUS二次开发功能,实现邓肯张本构模型及Goodman接触单元子程序的运用。(3)依托峡江水利枢纽工程同赣堤防建立考虑水力耦合作用的三维有限元模型,模拟溶洞灌浆、墙体施工、堤防填筑及蓄水过程墙体与覆盖层相互作用。研究表明,墙体承受典型的弯矩作用,溶洞的存在易出现应力集中,灌浆后有效降低墙后水头的同时墙体承担较大的应力。(4)研究防渗墙应力变形影响因素,主要考虑墙体弹性模量、渗透系数、覆盖层力学参数对防渗墙应力变形的影响。表明水荷载是墙体变形的主要原因,水平位移主要取决于墙后覆盖层承载条件,塑性墙能保持较好的应力状态。研究成果为掌握同赣堤防防渗墙工作性状提供了理论和技术支持,并可为其他类似工程提供参考。
[Abstract]:Seepage prevention technology of embankment foundation is a key technology in building water retaining structure on permeable foundation, and its success or failure is related to the safety of engineering. At present, the seepage prevention method of deep overburden karst foundation is concrete impervious wall combined with bedrock curtain grouting. This kind of bad geological engineering problem can be solved effectively by combining the advantages of impervious wall and curtain grouting. However, the impermeable wall is deep in the dam body or overburden, the stress condition is extremely complex, and it belongs to the hidden project, so the working performance of the impervious wall can be reasonably evaluated. In view of the extensive application of impervious wall in water conservancy engineering and the importance of seepage control system of dike dam, It is necessary to systematically analyze the seepage characteristics and bearing capacity of the impervious wall in deep overburden karst foundation. Based on the reasonable selection of the soil constitutive structure and the wall-soil contact element under the real condition, the fluid-solid coupling theory is used in this paper. A nonlinear mathematical model for the coupling analysis of seepage field and stress field of porous media material is established by using ABAQUS and secondary development function. The stress deformation and seepage behavior of impervious wall in deep overburden karst foundation are studied. The concrete research work in this paper is as follows: (1) the mechanism of controlling seepage deformation of embankment foundation is briefly summarized. It is put forward that the combination of impervious wall and curtain grouting is the main measure to solve the seepage problem of karst complex foundation in deep overburden. The seepage flow, the mathematical model of stress analysis and the solution of basic differential equation are introduced. On this basis, the mechanism of hydraulic coupling interaction and the realization of coupling equation are deduced. At the same time, the secondary development function of ABAQUS is used. The construction model of Duncan Zhang Ben and the application of Goodman contact unit subroutine are realized. Based on the three dimensional finite element model of Xiajiang water conservancy project and Jiangxi dike, the 3D finite element model considering hydraulic coupling is established, and the grouting of karst cave and the construction of wall are simulated. In the process of embankment filling and water storage, the interaction between the wall and the overburden layer is studied. It is shown that the wall is subjected to typical bending moment, and the stress concentration is easy to occur in the cave. At the same time, the wall bears the larger stress after grouting.) the factors affecting the stress and deformation of the cutoff wall are studied, and the elastic modulus and permeability coefficient of the wall are considered. The influence of mechanical parameters of overburden on stress and deformation of impervious wall shows that water load is the main reason of wall deformation and horizontal displacement mainly depends on the bearing condition of overburden behind the wall. The plastic wall can maintain a good stress state. The research results provide theoretical and technical support for mastering the working characteristics of the anti-seepage wall in the same Jiangxi dike, and can be used as a reference for other similar projects.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV223.4

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