【作者】 王超；

【导师】 徐力生；

【作者基本信息】 中南大学 ， 地质资源与地质工程， 2014， 博士

【摘要】 摘要：当前我国进入了水利水电工程大规模开发建设的关键时期,作为大坝基础施工主要加固手段的灌浆技术得到了大范围的推广运用。由于建坝高度的不断升级,灌浆加固坝基岩体以形成抗渗透能力强、耐久性好的基础防渗帷幕变得尤为关键。灌浆工程因是隐蔽工程,其施工质量和灌浆效果难以进行直观检测,必须要借助于对灌浆施工参数的分析来评定。由于受到压力波动、浆液流变特性和岩体裂隙几何结构特征等诸多因素的影响,灌浆质量检测和控制的自动化程度不高。尤其灌浆压力的反馈控制仍然采取人工调节以致其控制精度和控制响应时间无法满足工程实际的需要,且容易因操作失误致使灌浆压力超限而造成岩体张拉破坏、地层抬动变形,引起工程安全事故。基于以上情况,本文采取理论与实践相结合的方法,通过总结和归纳浆液在大坝基岩裂隙中的渗流特性来了解灌浆控制机理；通过分析和总结岩体变形效应及灌浆压力的计算方法来提出灌浆压力的综合设计原则；基于对灌浆压力波动机理的探讨、灌浆管路流体力学数学建模和自动控制分析,设计研发了灌浆压力自动控制系统(GPAC系统)；通过室内模拟灌浆试验和糯扎渡水电站坝基帷幕灌浆现场试验对该系统进行控制性能的验证和灌浆效果评价,以改进和完善系统。论文的研究工作主要包括以下内容：(1)讨论和总结灌浆压力的组成及其经验取值法、坝基帷幕灌浆压力的逆推计算法和灌浆试验确定最大灌浆压力法(包括常规压水试验和水力阶撑试验)；根据灌浆压力过大引起的水力劈裂效应、扩缝效应和压力挤密效应,详细分析这些岩体变形效应的发生机理及有利、可控的岩体变形发生时相应灌浆压力的计算方法。综合上述,提出了灌浆压力的综合设计原则与确定方法。(2)从灌浆管路系统的流量压降关系和浆液的流变特性出发,探讨了管路系统中灌浆压力的波动机理,认为：灌浆孔内地层的阻尼特性、调节阀的流量特性和运行开度以及灌浆泵的脉动特性是造成循环式灌浆管路系统内灌浆压力波动变化的主要影响因素。根据灌浆管路浆液一维流动模型的流量压降关系建立了管路系统的静态平衡控制方程组；根据可压缩流体的非定常流动,对灌浆管道中的瞬变流动进行动态瞬变分析,建立其基本微分方程,运用特征线法进行网格划分和有限差分,根据边界条件,用Newton-Raphson算法求其数值解,用一系列代表灌浆管道、管路设备、灌浆孔和调节阀的非线性代数方程组来简化和描述整个灌浆管路,并研究管路中基本组成部件的阻尼系数的计算方法,从而得出灌浆压力稳定性控制的量化计算控制量,进而提出灌浆管路中灌浆压力稳定性的流体力学模型,为编制灌浆压力稳定性计算软件提供了数学模型和控制参数。(3)根据常规PID控制和模糊控制的算法原理与控制器设计,分析和论述各自的优点和局限性。根据灌浆压力波动的特点、自动控制的精度要求和反应时间要求,将常规PID控制和模糊控制结合起来使用,提出具有参数自整定和控制规则自适应特点的复合式控制算法即基于T-S模型的模糊PID控制算法(TS-FPID算法)。(4)从软件界面、基本功能和硬件组成等方面详细介绍基于TS-FPID控制算法和灌浆管路系统流体力学模型的灌浆压力自动控制系统(GPAC系统)。GPAC系统上层软件采用SIEMENS WINCC V7和STEP7软件开发,控制系统底层采用SIEMENS S7-400系列可编程序控制器,系统网络采用PROFIBUS DP协议。(5)根据实际灌浆工况布设灌浆管路进行室内模拟灌浆试验,包括：灌浆泵脉动特性试验、电动调节阀阻尼系数试验、灌浆压力自动控制试验等。试验结果表明：当灌浆压力在0-5MPa内变化时,GPAC系统可在5-6s响应时间内实现压力自动控制,并将控制精度保持在压力设定值的5%以内,稳定性良好,达到了压力波动幅度的设计控制目标。在糯扎渡水电站坝基帷幕灌浆现场试验中,运用GPAC系统对灌浆压力进行实时检测和反馈控制。现场试验结果表明,试验区的灌浆效果显著,岩体裂隙和渗水通道被浆液充分填塞,岩体力学性能得到很大改善,岩层整体性更好,试验区防渗性能达到了设计要求的防渗标准。GPAC系统控制精度高、响应时间短、稳定性好,远远优越于人工控制,具有良好的工程经济性和安全性,可以在其他工程实践中推广应用。更多还原

【Abstract】 Abstract:With water conservancy and hydropower projects greatly enlarged in China at present, grouting technology has been widely used as a major reinforcement method of dam foundation constructions. As continuous upgrading for the height of concrete dam, the anti-seepage ability and durability of the foundation impervious curtain for high concrete dam become much more significant. Due to subtle characteristics of grouting engineering, both its construction quality and grouting effect are difficult to visually detect, which must be assessed by analysis on the grouting parameters. Because of the influence of many factors including pressure fluctuations, slurry rheological properties and geometry characteristics of rock fracture, automation degree of grouting quality monitoring and control are not high in practice now. In particular, the grouting pressure feedback control still take manual adjustment in which control accuracy and response time could not meet the actual needs, meanwhile engineering accidents are vulnerable to happen because of overrun grouting pressure caused by operational errors.In view of above, according to the methods of theory and practice, mechanism of grouting control are researched by analyzing the seepage characteristics of grout in fracture of rocky dam foundation, the integrated design principles of grouting pressure are proposed by analyzing rock deformation and calculate methods of grouting pressure, the grouting pressure automatic control system (GPAC) is developed based on the grouting pressure fluctuation mechanism studying, hydrodynamics mathematical modeling of grouting pipe network and automatic control theory analysis, GPAC system is improved by indoor grouting experiments and in-situ curtain grouting tests of Nuozhadu hydropower station. The major study contents are listed as follows:(1) The composition of grouting pressure and related calculation methods such as empirical method, reverse method of dam foundation curtain grouting, grouting experiment method including water pressure test and hydraulic jacking test are studied in detail. According to analyzing the occurrence mechanism of hydraulic fracturing effect, crack expansion effect and pressure compaction effect, the integrated design principles of grouting pressure is proposed.(2) On the basis of flow-pressure drop relationship of grouting piping systems and rheological properties of grouting slurry, fluctuation mechanism of grouting pressure is studied. Damping characteristics of grouting formation, flow characteristics and opening degree of regulating valve, and fluctuation characteristics of grouting pump are thought to be the main influencing factors causing the grouting pressure change in the circulating grouting pipe system. The static equilibrium equations of pipeline system are established based on flow-pressure drop relationship in one-dimensional model of grouting slurry flow in pipelines. In order to establish the basic differential equations of pipeline system, transient analysis on grouting slurry flow in pipelines is made based on hypothesis that flow is compressible and unsteady. Then characteristic method is used to mesh generation and finite difference, afterward, the equations are solved by Newton-Raphson method according boundary conditions. The whole grouting pipelines are simplified and represented as series of nonlinear algebra equations, which describe the grouting pipes, equipments, grouting hole and regulating valves. Meanwhile calculation methods on damping coefficients of fundamental composition in grouting system are studied in order to provide accurate calculation control values for pressure stabilization. Finally, the hydrodynamic model of grouting pressure stabilization and related control parameters is proposed for programming pressure fluctuation control software.(3) The algorithm principle and controller design of PID control and fuzzy control are studied in order to summarize their respective advantages and limitations. According to the fluctuation characteristics of grouting pressure, control accuracy and response time requirements during automatic control process, a set of composite control algorithm with particularities of parameter self-tuning and adaptive control rules which named as TS-FPID is proposed by combining the PID control algorithm and fuzzy control algorithm.(4) Grouting pressure automatic control system (GPAC) which based on hydrodynamics mathematical modeling of grouting pipeline system and the TS-FPID control algorithm is illustrated in detail through the software interface, basic functions and hardware composition. The upper software of GPAC system is developed on SIEMENS WINCC V7and STEP7, the hardware of GPAC system is composed by SIEMENS S7-400programmable logic controller (PLC), PROFIBUS DP is used as system network.(5) Indoor simulation grouting test such as grout pump pulsation characteristics tests, regulating valve damping coefficient tests, grouting pressure automatic control tests and etc are performed according to the actual grouting conditions. The simulation results show that grouting pressure can be automatic controlled in5-6s and control precision can be kept on less than5%of designed pressure value by GPAC system when the grouting pressure changes in the range of0-5MPa, the design target of pressure fluctuations control is met. GPAC system is used for real-time monitoring and feedback control on grouting pressure in dam foundation curtain in-situ grouting test of Nuozhadu hydropower, the test results show that grouting effect of test zone is well, rock fracture and water seepage channel are fully packed by slurry whilst mechanical properties of rock mass and strata integrity are greatly improved, the design standard of anti-penetration capability is met. Compared to manual regulation, control accuracy and response time of GPAC system are more superior which have better benefit on engineering economic and security in addition. GPAC system should be promoted to widely use in other engineering practice.更多还原