Study On The Construction Quality Control And Evaluation Of High Fill Subgrade In The High Speed Railway Section Under Shield

As a key part in the construction of high-speed railway,the quality of roadbed construction will directly affect the quality of the whole project.Because of the safety accidents caused by subgrade problems shocking our heart,people pay more and more attention to the quality of subgrade construction.Compared with the ordinary subgrade,the high filling subgrade is high in height,and it is difficult to control the compaction quality of the subgrade when the layered filling is carried out.The large amount of filling makes it have a large self-load,which is easy to cause the uneven settlement of subgrade.High fill embankment and shield tunnel intersect each other,more uncontrollable factors,when the shield tunnel construction on the surrounding soil disturbance,soil by stress by pile up to subgrade plate structure,causing uneven settlement of subgrade,affect the quality of high fill subgrade construction.When the construction quality of high fill subgrade is wrong,not only the railway construction project will be seriously affected,but also the subsequent traffic safety may be endangered.Therefore,it is an effective means to improve the construction quality of the high-fill subgrade under crossing section by identifying the key elements affecting the construction quality,giving key control during construction,using practical methods to evaluate the construction quality of the subgrade and putting forward construction quality control measures.In this paper,the construction quality of the high fill subgrade in the underpass section is studied as follows:(1)In the first place,on account of the construction background of the project and incorporation the project characteristics conduct analysis and research,read the related literatures to realize the actuality research situation of high fill subgrade construction quality control,recommend the domestic and foreign scholars in the research of high fill embankment quality control focuses on indicators,for the selection of high fill subgrade construction quality control indicators provide a theoretical basis.Incorporation with the features of the construction of high fill subgrade in the underpass section,the principal impacting elements of the process of construction quality of high fill subgrade are analyzed from multiple dimension,the affecting elements are summarized and reclassified,and the construction quality evaluation index system is constructed.(2)Secondly,the selected evaluation indexes are used as variables,and the objective entropy weight method is used to determine the relationship between the indexes,and the quantitative processing of each index is carried out.At the same time,based on the extension theory,a multi-level extension evaluation model is built which is not affected by the quantity,dimension and information repetition of the indicators.Combined with the construction project of high-speed railway high-fill subgrade under construction of shield tunnel in a certain area,the multi-level extension evaluation of the construction quality of high-fill subgrade is carried out,and the evaluation result of the construction quality of the overall objective is obtained.(3)In the final analysis of multi-level extension evaluation results,from point view of construction supervision and technology,come up with the concreteness methods of high fill subgrade construction quality control,and monitor the sediment of high fill roadbed,on the basis of monitoring data analysis of high fill embankment filling stage whether settlement within a rational range,to guarantee the process of construction quality of entirety high fill roadbed,as hereafter analogous intersect section underneath pass construction projects quality command to afford a certain amount of consults.