| Railway subgrade is track structure based and bear the load of trains and track, if the strength and stability of does not meet the requirements, will affect the line quality, train speed, track maintenance workload increased, serious will endanger the safe driving. In recent years, with China’s economic development needs, axle load, high density traffic exacerbated the damage of the railway subgrade, due to the sinking of the railway roadbed is extremely serious consequences, the management methods must be both the effectiveness and timeliness. This paper on the basis of previous studies, the use of oblique high pressure jet grouting technology on the existing railway subgrade reinforcement project.Combining with Xinjiang Railway Kui line K339+000~K344+000 subgrade settlement deformation research governance, follows the questions, analyze problems, to solve the problem of research, combined with laboratory test, field test and numerical simulation techniques, for oblique to the high pressure jet grouting technique in the relatively rigorous research.First of all, through the detailed investigation and analysis, the main performance of Kui Northern Railway K339+000~K344+000 subgrade diseases as: bridge transition section sinking serious, larger longitudinal cracks on the shoulder and roadbed subsidence caused by slope protection framework muster etc.. The main causes of the roadbed diseases are as follows: the roadbed filler is poor, the roadbed compaction degree is insufficient, etc.Then, the influence of grouting pressure, water cement ratio, the rate of drill bit, and the angle of drill pipe on the grouting effect is analyzed and summarized. The results showed that the grouting pressure, the incident angle of drill pipe and the lifting speed of the drill bit have great influence on the shape of the jet grouting pile, and the strength of the pile is small, and the water cement ratio has great influence on the shape and strength of the pile. Based on the field test of vertical settlement monitoring found that the vertical displacement of the greater the corresponding section of the grouting pressure is greater. The comprehensive influence of various grouting parameters of the grouting effect, this paper recommended the grouting pressure is 20 MPa, water cement ratio is 1:1,pipe lifting speed is 15cm/min,air pressure is 0.7MPa, drill the incident angle of 10°~15°.Then, in view of the influence of pile form and reinforcement effect relationship by FLAC3 D numerical simulation it is found that the "plum" shaped cloth around the pile of the pile body are of subgrade soil, and no can withstand the embankment top load "bearing layer", therefore, "plum" shaped pile has limitations, can only meet the railway subgrade reinforcement under certain conditions; and the "subgrade bite" pile reinforcement, the vertical stress distribution is more uniform and more broad, the subgrade of the vast majority of soil plays bear the upper load, the subgrade integrity is obviously improved and the use of "bite" pile of existing railway the subgrade settlement control is very effective, and the pile spacing is 2m can meet the requirements. Due to the subgrade cross section is a trapezoid, and cement soil consolidation for hard layer, so in the subgrade slope and "bite" pile intersection of soil squeezing effect will appear a small range of extrusion phenomenon. This can be through the adoption of appropriate reinforcement of roadbed and eliminate, so does not affect the "bite" pile of overall reinforcing effect.Finally, the technical characteristics of high pressure jet grouting reinforcement of existing railway subgrade, put forward by inclined jet grouting reinforcement technology of existing railway subgrade construction technology. |
