Study On Grouting Technology Of Completely Weathered Granite Stratum

At the same time of the rapid development of China's infrastructure construction,a large number of projects involve the anti-seepage reinforcement of fully weathered granite strata.Grouting is one of the effective means of foundation treatment.It is often used because of its simple construction and strong adaptability.The fully weathered granite stratum is dense and gravel-like,with fine fissures developed and easily softened and disintegrated in contact with water.For the grouting of this type of stratum,the prior art has poor groutability in the grouting material,and even more inability to infuse,or excessive pressure,splitting and running,etc.;in the grouting process,the borehole is easy to collapse,the grouting pressure It is difficult to control;the grouting theory is mostly concentrated on the study of single penetration,compaction and splitting,far behind engineering practice.In view of the above problems,this paper systematically carried out research on the grouting mechanism,materials and processes suitable for such strata in the fully weathered granite stratum.The main contents and achievements are as follows:(1)Combining the characteristics of fully weathered granite stratum and the theory of groutability of grouting material,the diffusion law of slurry in the stratum is analyzed,and the infiltration-cracking composite grouting mechanism of the fully weathered granite stratum is proposed,and the viscosity of the slurry is considered.The relationship between the denaturation and the pressure drop of the tension is obtained.The relationship between the diffusion radius of the slurry and the grouting amount,grouting time and grouting depth is obtained.(2)Using the stupid high-efficiency water reducing agent FDN-C and polycarboxylate superplasticizer,the whole weathered granite permeable grouting material,wet grinding clay cement slurry,which was studied in the previous research group,was improved.The sample laboratory test compares the basic properties of the improved slurry and the mechanical properties of the stone.It is concluded that the performance of the slurry is better by using the stupid high-efficiency water reducing agent FDN-C.(3)Indoor grouting test of different grouting materials(wet grinding clay cement slurry before and after improvement)on fully weathered granite soil under different pressure supply modes(stabilization and pulsation),parameters of grouting process and post-irrigation effect The analysis shows that the improved wet-grinding clay cement slurry is pulsating grouting mode,and the stone body becomes uniform and regular cylinder after filling.The diffusion law is consistent with the seepage-cleavage grouting mechanism.(4)On-site applicability test of conventional grouting materials and processes and new materials(improved wet-grinding clay grout)and grouting process(high pressure pulsation,drilling and irrigation integration)in Bangan Reservoir,Honghe Prefecture,Yunnan Province.:The conventional grouting material and process test can not form a good anti-seepage curtain.The water permeability after filling can not meet the design requirements.The new material and new technology have good anti-seepage effect and the water permeability after filling meets the design requirements.