Deformation Timeliness Analysis Of The Middle-Lower Compressive Soil Of High-Speed Railway Based On Geotechnical Centrifuge Model Tests

In order to meet the train safety, high speed, stable, comfortable operation, track structure should have a high degree of comfort and stability. The subgrade settlement is one of the important factors affecting the long-term service performance of high speed railway, the cumulative plastic deformation of subgrade and below the bedding the embankment and foundation settlement deformation. Because the accumulation of subgrade filling part of plastic deformation and consolidation settlement by selecting high quality filling and compaction standard of effective control, so the long-term deformation of foundation under embankment load is the major source of high-speed railway subgrade settlement after construction, analysis of the deformation law of development, it can provide reference for the evaluation and control of post construction settlement.Due to the low compressibility of hard clay, sand soil, gravel soil, weathered rock foundation is the lack of profound understanding of the long-term deformation characteristics, in the high speed railway existing ballastless track subgrade construction, this kind of foundation are made of high strength pile composite foundation of reinforcement. But the field test and monitoring data often show, roadbed settlement are relatively small settlement and post construction, so it’s important to carry out the high-speed railway ballastless track low compression soil settlement based control technology research. In this paper, the main work and achievements are as follows:(1) The foundation of Ji Hun of Railway Passenger Dedicated Line silty clay of disturbed soil samples for the indoor geotechnical centrifuge model test, designed a set of time effect of deformation of the foundation settlement simulation scheme, to study the influence of the height of embankment and foundation soil compression state of the deformation of the foundation settlement. Among them,3m,6m,9m embankment three height, based on the principle of equal weight geometric similarity using plate was simulated; The model of foundation soil preparation and model construction and testing, model foundation in weight and 3m,6m,9m high embankment settlement under centrifugal load deformation test.(2) Combining the indoor geotechnical centrifuge model test, according to the loading and unloading process test of concrete, using the equivalent - shift method to process the test data, deformation curve from a loading and unloading process time displacement curve obtained directly loading time; Based on the theory of superposition of genetic, the measured deformation genetic method and real deformation genetic law two methods of P value was fitting, In the 3m,6m,9m under embankment load, according to the measured deformation genetic method to fit the P values were 1.413,1.061 and 1.062, according to the real deformation genetic method to fit the P values were 1.413,1.165,1.183, two methods have good consistency. Clear how by test data of graded loading, get the sample loading data, the deformation of geotechnical centrifuge model test technology and data processing method of a time effect of foundation under embankment load.(3) The long-term plastic deformation rate can be based on power function v(t)= at-p expression, the long-term plastic deformation and time: . Using the fitting formula for different loads the P values were fitting, and the model of foundation soil state settlement under embankment load at different height are divided, to verify the effectiveness of foundation compressed layer thickness " fractal dimension criterion".