| The dam foundation grouting is one of the important measures to improve the geological conditions of dam foundation.However,due to the concealment of the geological conditions of dam foundation,the uncertainty of grout diffusion in rock fracture and the complexity of the grouting construction technology,the accurate control of the grouting construction quality is extremely difficult.Existing grouting construction quality control studies cannot monitor and analyze the grouting parameters in real time and lack of the ablity of dynamic early warning and control of the situation that the uplift of the bedrock as well as the poor grouting performance.In addition,it is difficult to comprehensively evaluate the quality of grouting from both the aspects of permeability and tightness with the existing evaluation method of grouting quality.As a result,it is difficult to accurate control the grouting construction quality in real time,in turn,it's necessary to perform multiple reinforcing grouting for the quality defects caused by the failure of grouting quality control.Therefore,how to solve the problems of accurate control of grouting construction quality become a significant subject to be researched in the dam foundation grouting engineering field.In this article we make further research on the above problems.The main research results are as follows:(1)In order to solve the problem that existing researches of grouting construction quality control lack the real-time and post-action control abilities.This paper proposes the theory of construction quality control for dam foundation grouting projects,which makes it possible to finely control the construction quality from the perspectives of both real-time control and post-control.Existing researches of grouting construction quality control lack real-time control of grouting quality according to real-time monitoring and analysis of grouting parameters and groutability.Besides,because existing grouting quality evaluation methods lack comprehensiveness,it is difficult to control the grouting construction quality accurately.Therefore,in order to improve real-time capability and accuracy of grouting construction quality control,this paper proposes the construction quality control theory of dam foundation grouting projects.According to this theory,the grouting construction quality is controlled during and after grouting process based on real-time monitoring and analysis of grouting parameters,groutability analysis and comprehensive evaluation of grouting quality.First of all,the characteristics of the dam foundation grouting projects are summarized,and the process of grouting construction are analyzed.Secondly,the dam foundation grouting engineering system is decomposed from a complex large scale system to many simple and controllable subsystems.Furthermore,the grouting construction quality control methods and control objectives is proposed based on real-time monitoring and analysis of grouting parameters,groutability analysis and comprehensive evaluation of grouting quality,and the theoretical framework of construction quality control for dam foundation grouting projects is constructed.Consequently,the mathematical model of construction quality control for dam foundation grouting projects is established,which defines the state equation of the control system,the objective function,the control method sets and the constraint condition sets.(2)In order to solve the problems that existing researches of grouting construction quality control have not combined real-time monitoring and analysis of grouting parameters,this paper proposes the real-time monitoring and analysis method of grouting parameters to real time control the dam foundation grouting construction quality based on real-time monitoring and early warning of grouting parameters.Existing researches of grouting construction process control lack early warning and control for abnormal situations according to real-time monitoring and analysis of grouting parameters.Therefore,in order to finely control grouting construction quality during grouting construction process,the real-time monitoring and analysis method of grouting parameters is proposed.Firstly,the research framework and mathematical model of the real-time monitoring and analysis method of grouting parameters are established.Secondly,the methods of real-time collection and transmission of grouting parameters,including the collection methods of grouting pressure,flow rate,grout density and uplift value and the wireless transmission methods of grouting parameters,is introduced.In addition,the method of real-time monitoring and dynamic early warning of grouting parameters is proposed.According to real-time monitoring and analysis of the grouting parameters,abnormal conditions caused by the change of grouting parameters can be detected and dynamicly early warning in real time,and early warning information is timely sent to the grouting managers and construction workers in order to take appropriate measures to adjust and control grouting.Finally,by combining with three-dimensional(3D)grouting models,the method of 3D grouting visualization is proposed.Grouting parameters will be coupled with 3D grouting model,and then the grouting parameters,grouting construction process and results can be analyzed and displayed in 3D grouting models.(3)In order to solve the problem that existing researches of groutability analysis lack quantitative analysis methods and construction quality control according to groutability analysis,this paper proposes the method of groutablity analysis.This method realized real time control of construction quality for dam foundation grouting projects with quantitative groutability analysis.Existing researches of groutability analysis have not taken the quantitative relationship between the permeability of the rock mass and the grout take into consideration,and lack the feedback control for the grouting construction quality.Therefore,in order to improve the scientificity of the groutability analysis,the method of groutability analysis based on the relationship of cement take and transmissivity is proposed.Based on this method,feedback control of grouting construction quality is carried out.Firstly,good groutability is defined.Secondly,based on the fractal theory of the fracture network and the relationship of the fracture length and fracture aperture,the relationship between the transmissivity and the fractal dimension is derived.Thirdly,based on the relationship of the cement take and the fractal dimension,the relationship between the cement take and the transmissivity is derived.According to the curve of the relationship between the cement take and the transmissivity,three grouting areas are delimited and defined: "normal area","tiny fracture area" and "dilation area".Finally,based on the seepage control standard of dam foundation and the grouting areas,the groutability areas are delimited,based on which quantitative groutability analysis is realized.According to groutability analysis,measures have been taken to deal with the poor groutability areas which need to be grouted,thus to improve the groutability of grouting and make sure that the fractures under dam foundation can be better grouted,thereby improving the grouting quality.(4)In order to solve the problem that existing researches of grouting quality evaluation methods lack integraty and comprehensiveness,this paper proposes a hybrid fuzzy comprehensive evaluation method for grouting quality assessment.According to the evaluation results and appropriate treatment,the post-control of construction quality for dam foundation grouting is achieved.Due to the concealment and complexity of dam foundation grouting,the accurate control of the grouting construction quality is extremely difficult,therefore,it is necessary to check and evaluate grouting quality after grouting construction.However,nowadays,single factor evaluation method is most frequently used in grouting quality evaluation.it is difficult to assess the permeability and tightness for rock mass after grouting,and neither integrative nor comprehensive.In order to improve the integraty and comprehensiveness of grouting quality evaluation,this paper proposes a hybrid fuzzy comprehensive evaluation method for grouting quality assessment.Based on the three indices which are permeability rate,rock quality designation(RQD)and fracture filled rate(FFR),The method estimate the grouting quality from the perspectives of both permeability and tightness.Firstly,the evaluation framework and mathematical model are established.Secondly,a model of grouting quality evaluation system is constructed,and the the methods of evaluation indices acquisition and calculation are introduced.Furthermore,the approach to solve this evaluation model is proposed.Considering that the determination of the weights of evaluation indices is a fuzzy decision making problem,the D-AHP is introduced to calculate the weight of each index.Since grouting quality evaluation is a multiple factors system,in which the effect of each index on the objective and relationship between each index are fuzzy,it is necessary to take advantage of fuzzy comprehensive evaluation method to give an overall consideration of the grouting quality.Finally,by combining fuzzy comprehensive evaluation method with D-AHP method,the solution steps are given to calculate the grouting quality evaluation model.According to the grouting quality evaluation,the faults of grouting will be better revealed and the feedback control will be proposed to overcome the weakness.(5)Based on the methods of real-time monitoring and analysis of grouting parameters,groutability analysis and grouting quality comprehensive evaluation,this paper proposes the specific process and the methods of the construction quality control for dam foundation grouting projects.According to the theory of the construction quality control for dam foundation grouting projects,the grouting construction quality control method is proposed based on the methods of real-time monitoring and analysis of grouting parameters,groutability analysis and comprehensive evaluation of grouting quality.Firstly,according to the grouting construction technology and procedure,the overall control process of the construction quality of dam foundation grouting projects is established.Secondly,grouting quality real-time control method which based on the real-time monitoring and analysis of grouting parameters is illustrated in detail.According to real-time monitoring and analysis of the grouting parameters during grouting construction,abnormal situations such as bedrock uplift are detected by real-time dynamic early warning,and then the warning informations are sent to managers and constructors of grouting construction in real time.At the same time the appropriate corresponding treatment measure are taken to control grouting.Furthermore,grouting quality control method based on the groutability analysis is illustrated in detail.According to the relationship between cement take and transmissivity,the grouting areas and groutability areas are identified and classified,then the corresponding measures according to the groutability analysis result are taken to get better grouting quality,to ensure that better groutability can be obtained without the damage of bedrock structure,consequently the quality of grouting construction can be improved.Finally,grouting quality post-control method based on the comprehensive evaluation method of grouting quality is illustrated in detail.Through the comprehensive evaluation of grouting quality,the weak parts of the grouting quality which traditional method cannot reveal can be exposed,the decision-making and technical support for the targeted treatment of reinforcement grouting can be provided. |
PDF Full Text Request