Study On The Centrifugal Model Test Of Embankment Filled With Xigeda Strata

In recent years, with the high-speed economic development, infrastructure construction have ushered in unprecedented opportunities. Provinces such as Yunnan, Guizhou, Sichuan, Chongqing, are mountainous, mountain area accounts for more than 85%. of Western China. This special topographical condition will result in a large number of high-filled embankment engineering in the process of infrastructure construction in the west of China. The stability of the subgrade is essential to railway operation safety. Compared with the common embankment, the high-filled embankment has more requirements to embankment filler and construction technics.This paper was supported by the construction of Panzhihua South Railway Station along Chengdu-Kunming Railway, based on the DK592+120 embankment section. The deformation characteristics and stability of high-filled embankment in Xigeda strata were studied by the centrifugal model tests. Different compactness, slope rates and reinforcement measures were considered to divide the tests into three groups. The tests collected data of displacement and soil pressure by the static data collection system. By analyzing the test data, the law of settlement in construction was summarized, the post construction settlement was forecasted, the relation between soil pressure and slope location were analyzed. Furthermore, the simulation models of the three tests were established and analyzed. The settlement under 0～200 times gravitational acceleration were calculated by numerical simulation. And the comparison between the centrifugal model tests and the numerical simulation was made. The slope stability was studied according to the actual working conditions. The main work and conclusions of the study are as follows:(1) Through the centrifugal model tests, the construction settlement of models and the post construction settlement in 4 years and 7 months were obtained. The maximum settlement during the construction occurred on the subgrade surface,1023 mm of M1,217 of M2,179 of M3. With the improvement of compaction, the strength of embankment increased, the settlement decreased.(2) With the initial settlement parameters of the centrifugal model tests, the post construction settlement curves in 100 years were forecasted based on the hyperbola method according to engineering experience. All of the results of the three tests met the standard requirements which limit the post construction settlement in 200mm.The settlement rate of M2 was the largest, then M1, M3 had the lowest settlement rate. All of the three tests fit the standard requirements about the rate of the post-construction settlement.(3) By analyzing the results of centrifuge model tests, it showed that the settlement of the subgrade during construction period can be reduced by using the geotechnical grid. The three-step high subgrade with the geotechnical grid could reduce the lateral stress difference between the points at different horizontal positions in soil. The geotechnical grid Limited the lateral deformation of the embankment and improved the stability of the embankment, leading to a good engineering effect.(4) The models were analyzed by the numerical simulation, the numerical simulation results and the centrifugal model test results were compared. The numerical simulation could reflect the settlement trend of model tests, but it failed to reflect the phenomenon of uplift in the experiments.(5) The safety factor of each group was obtained by numerical calculation. It was proved that the compaction effect on the stability of the slope was more significant than the slope rate. And the high-filled embankment using Xigeda soil with a compaction more than 93% could meet the stability requirements.