Cleavage Characteristics Of Sleeve Valve Pipe Grouting Soil And Nondestructive Evaluation Based On Acceleration Response

Under the influence of external adverse factors such as heavy rainfall,train dynamic load and engineering disturbance during the years of operation of the existing railway subgrade,the settlement problems of the loess-filled subgrade are prone to occur,which is reflected in the track geometry and reduces the railway Transport capacity affects the safe and smooth operation of railways.Sleeve valve tube grouting reinforcement technology is a good choice for the treatment measures of roadbed settlement without affecting the operation of the railway.Based on the Tianshui-Lanzhou section of the Longhai Line,the sleeve valve tube is used to treat the subgrade settlement disease.The field investigation and data collection are used to summarize the causes of the settlement.The model test and numerical analysis of the sleeve valve tube reinforced subgrade are carried out,and the sleeve valve tube is summarized.Splitting characteristics of grouting on soil,and destructive testing and non-destructive testing of grouting effect based on acceleration response at the construction site to detect subgrade reinforcement effect.The research results have certain reference significance for similar projects.1.The soft soil under the subsidence road may extend to the soil below the bottom of the bed(6m~9m);after grouting in this section of the roadbed,there will be a temporary decrease in strength,but after the slurry solidifies,the strength will increase significantly It is obvious that this part of weak soil has a strong reinforcement effect.2.The increase in the earth pressure and the periodicity of the soil on the upper part of the sleeve valve tube are more obvious.In general,the sleeve valve tube needs to pass through the weak layer of the soil body for grouting,so that the soil may be split and compacted.will be better.3.The reinforcement effect of the sleeve valve tube is mainly manifested in three aspects: the expansion of the casing material itself under pressure squeezes the surrounding soil,the formation of a large shell-like splitting vein in the dense soil layer,and the formation of nodules The stone-like stones are embedded in the soil;the earth pressure data shows a strong stage.This article divides it into infiltration stage,compaction,splitting stage and strengthening stage: the increase of earth pressure presents randomness,different monitoring There is no obvious rule on the cross section;the peak value of earth pressure and its arrival time are related to the normal distance from the sleeve valve tube and the state of the soil layer;both in the grouting state and during the intermittent period,there are slurry penetration and splitting,intermittent grouting may be more beneficial to the soil Body fluid filling.4.Using FLAC3 D to analyze the state of the subgrade before and after grouting,it is believed that after grouting reinforcement,the settlement and plastic zone distribution of the subgrade under static and dynamic conditions are greatly reduced,and the PGA amplification factor increases uniformly along the elevation.The mutation point disappears,and the roadbed is intact.5.The grouting effect was comprehensively tested by means of grouting anatomy,destructive borehole observation and non-destructive evaluation based on acceleration response of the waste roadbed.Focus on the evaluation of the grouting effect based on the acceleration response.After the treatment,the acceleration response of the subgrade whether under the dynamic load of the passenger car or the truck is significantly enhanced.In the numerical analysis,the shoulder shoulder measurement point also has this phenomenon.Indirect It proves that the stiffness and compactness of the roadbed are improved after grouting,and the sleeve valve tube is considered to be more successful in this segment.6.However,the results of the rail inspection trolley show that there are some road sections with ineffective treatment effects,and even a small amount of aggravation.There may be problems such as slurry leakage at the bottom of the subgrade.More extensively,it is necessary to specifically discuss the grouting construction in the filled subgrade combined with local engineering conditions to improve the treatment plan.