Theory And Application Of High Core Rockfill Dam Settlement Analysis Based On Real-time Monitoring Of Rolling-compaction Quality

During the construction process,the high core rock-fill dam will produce a deformation under the coupling effect of the dead load and the water pressure.And these loads are constantly changing with the construction process.Therefore,the dam deformation is of strong dynamics and non-linearity.The controlling of the deformation is the key to success of the high core rock-fill dam construction,and it is a hot issue in the research field of dam construction safety control.The existing research of high core rock-fill dam deformation analysis is limited by the data acquisition technologies and methods,so that it is difficult to realize the real-time updating of the modeling data for deformation analysis.These issues also make it difficult to accurately describe the dynamic change of the influence factors,and difficult to expose the law of space-time distribution of dam deformation.In this paper,the real-time monitoring technology of compaction quality was used to obtain the construction process information of the high core rock-fill dam.Combined with the characteristics of dynamic non-linearity and uncertainty of the deformation analysis,the high core rock-fill dam deformation analysis considering the construction quality has been studied deeply,and the following results are obtained:(1)the theory framework of settlement deformation analusys based on real-time monitoring of construction quality is presented,and the theory of settlement deformation analysis of high core rockfill dam based on real-time monitoring of construction quality is put forward,and the mathematical model of settlement deformation analysis of high core rockfill dam with considering the quality of construction is established,which provides the theoretical support for analyzing the settlement and deformation of high core rockfill dam.The compacted construction quality factor of dam is one of the important factors in the analysis of settlement deformation of high core rockfill dam.In the existing study,the scholars always regard the same filling area as a homogeneous body,without taking the heterogeneity of the compaction density of the dam due to the difference in construction quality into account.First,through the analysis of the influence mechanism of construction quality and settlement deformation,the settlement and deformation analysis mathematical model of the high core rockfill dam considering the construction quality factor is established to achieve the parametric description of method of the dam settlement deformation analysis.Secondly,in order to analyze the influence of construction quality factors in dam filling and compaction,the mathematical sub-model of construction quality evaluation of high core rockfill dam is established.The target control function and the research method are analyzed in detail,and the various influence factors indicators such as construction scheme,construction machinery parameters and dam material performance are decomposed,which provide a theoretical basis for the selection of construction quality factors in dam settlement and deformation.Finally,the mathematical sub-model of settlement deformation analysis of high core rockfill dam is established.The target control function and the research method are introduced in detail,and the various influence factors,boundary conditions and optimal control conditions are decomposed,which provides the theoretical basis for the settlement deformation analysis.(2)Combined with the dynamic nonlinear characteristics of settlement process,a method of settlement deformation analysis of high core rockfill dam based on improved M5'-PCR model tree is proposed.This method overcomes the dynamic updating problem of settlement deformation analysis model and realizes the dynamic analysis of settlement deformation of high core rockfill dam during construction period.There are many influencing factors of settlement deformation and the expressions of the factors are various.The real-time monitoring data of rolling quality can more accurately analyze the dynamic nonlinear relationship between the settlement deformation and the influencing factors of the high core rockfill dam.Then the factors of settlement deformation can be selected through correlation analysis.The principal component analysis is used in this paper to reduce the dimension of the influence factor to the low dimensional space,while retaining the main information.Aiming at the dynamic nonlinear problem of the settlement and deformation of high rockfill dam,this paper introduced the M5' model tree into the field of dam deformation analysis.It can make up for the deficiency of traditional regression analysis model as a piecewise linear global model.Firstly,the input parameters are determined by correlation analysis of the input parameters and their expressions.The M5'-PCR model tree is modeled by three stages: splitting,pruning,and smoothing.But the M5'-PCR model tree can easily identify the significant influencing factors as noise,so the multivariate linear regression analysis is replaced by the principal component regression analysis model at the node to realize the noise recognition of influencing factors.The improved M5'-PCR model tree divides the relationship between dam deformation and influencing factors into several independent linear models,in which the regression parameters of each model variable can be determined.Compared with the measured settlement,it is verified that the fitting accuracy of the improved M5'-PCR model tree meets the requirements.By comparing the absolute difference and root mean square error,the predicting results of the improved M5'-PCR model tree and M5 'model tree,multiple linear regression model and principal component regression analysis model were compared.The results show that the improved M5'-PCR model tree has a higher accuracy for predicting dam settlement,and the correlation illustrates that the propsed daynamic nonlinear analysis method of settlement deformation is in high ralibility,which provides a new way to analyze dam deformation.(3)To overcome the uncertainties of influencing factors in construction quality of high core rock-fill dam,a cloud-fuzzy model method for construction quality assessment based on real-time monitoring of rolling compaction quality is put forward and the monitoring of rolling compaction quality assessment for high core rock-fill dam is realized,which provide a new way to analysis the factors affecting the settlement deformation of dam when filling and rolling.The influencing factors on the quality of the dam compaction are numerous,and have strong randomness and fuzziness.Current construction quality assessment of high core rock-fill dam uses multivariate linear regression and artificial neural network.These methods do not consider the uncertainty of construction quality.The uncertainty of factors affecting construction quality is analyzed by cloud model,and classified by fuzzy linguistic.The fuzzy neural networks are improved by the basic theory based on cloud model,and the cloud-fuzzy model combining the ability of fuzzy inference and uncertainty analysis is established.A cloud-fuzzy method based on real-time monitoring of rolling compaction quality for construction quality assessment of high core rock-fill dam is proposed,the construction parameters and material parameters are matched according to the same space,and by cloud analytics for construction parameters and material parameters,the parameters of cloud-fuzzy model are determined and used for fitting and prediction of dry density.The results show that cloud-fuzzy model can predict more accurate and more realistic compared with Improved BP neural networks model,RBF neural networks model and multivariate linear regression model.Assessment method for construction quality of working unit is proposed based on the assessment of dry density using cloud-fuzzy model to predict.Combining with the high core rock-fill dam construction,the assessment of construction quality is researched based on the cloud-fuzzy model and assessment method for construction quality of working unit.The results show that the construction quality of unit which is selected is good.(4)Based on the real-time monitoring of rolling quality and the results of cloud-fuzzy evaluation,the settlement deformation model of high core rockfill dam considering the construction quality factor is established.Based on the improved M5' model tree,a settlement analysis method considering the construction quality factor is provided and the settlement deformation process is analyzed,which provides scientific support for exploring the spatial distribution of the settlement deformation of the high core rockfill dam.At present,the settlement deformation analysis of high core rockfill dam is focused on the study of the relationship between settlement and influencing factors.There is short of the study of the influence considering construction quality factor on settlement deformation.In this paper,the characteristics of the dam material are analyzed and the expression formula of the aging factor impacted by filling factor is deduced through empirical analogy.The settlement deformation model of high core rockfill dam with consideration of construction quality factor is established.Based on the improved M5' model tree,the settlement and deformation analysis method of high core rockfill dam based on real-time monitoring of roller construction quality is put forward.The predictive analysis of settlement process is achieved with the settlement deformation model of high core rockfill dam considering the construction quality factor.According to the engineering application example,it is shown that the settlement analysis method of dam considering the effect of construction quality is superior to those which does not take into account the influence of construction quality.And based on the real-time monitoring of rolling quality,the settlement deformation analysis method in which construction quality is considered can reveal the spatial distribution of the settlement deformation of the monitoring area more accurately than those traditional analysis methods,which makes up the shortcomings that the traditional analysis methods can't provide the deformation control of the high-wall rockfill dam outside the monitoring point and provides more reasonable theoretical basis and technical guidance for the safety control of site construction of high core rockfill dam.At the same time,the correlation illustrates thehe settlement deformation model of high core rockfill dam considering the construction quality factor is raliable.The settlement settment analyzed through the settlement deformation model of high core rockfill dam considering the construction quality factor is in control,which supports that the compaction quality real-time monitoring system gyarantees the construction quality of high rockfill dam effectively.