With the development of high-speed railway in China, composite foundation with rigid piles has become a stamdard solution of meeting the high requirements of stability and post-construction settlement of embankment on...With the development of high-speed railway in China, composite foundation with rigid piles has become a stamdard solution of meeting the high requirements of stability and post-construction settlement of embankment on soft subgrade. Among several im- provement pattems, plain concrete piles have been extensively used to treat soft ground supported embankment. To investigate the deformation and failure modes of unimproved soft ground and soft ground reinforced by sub-embankment plain concrete piles, and to learn the influences of track and vehicle load, the effect of pile spacing, as well as the compression moduli of soil layers and upper load condition on the failure modes, a series of centrifuge model tests were performed. Test results indicate that the dis- placement of unimproved soft ground under the embankment increases continuously as embankment, track and train loading, and slip circle failure takes place. The deformation law of soft ground reinforced by sub-embankment plain concrete piles depends on pile spacing, compression modulus of the soft ground, and loading conditions. It was also found that plain concrete piles show displacement and failure patterns depending on its location, compression modulus of soft soil around the pile, and loading condi- tions. Furthermore, the evaluation of improved ground stability as well as the model test procedure is also presented.展开更多
A physical model facility was designed,built,and setup for conducting model tests on a composite foundation in a soil ground.The model tests were carried out on a composite foundation with different combinations of ve...A physical model facility was designed,built,and setup for conducting model tests on a composite foundation in a soil ground.The model tests were carried out on a composite foundation with different combinations of vertical reinforcement elements in the same soil ground.Via the analysis of the collected data the characteristics of the composite foundation with different reinforcing elements were obtained,including the characteristics of load-settlement curves,column stresses,stresses of the inter-column soil,pile-soil stress ratio,and load-sharing ratios of columns and soil.Results from the model tests reveal the mechanism of a composite foundation with different reinforcing elements quantitatively.It is concluded that both a composite foundation with a combination of steel pipe pile and sand column and that with a combination of concrete pile and lime column have a higher bearing capacity than the composite foundation with only sand columns with the same conditions of soil ground and loading.A composite foundation with lime column and sand column embodies no much better performance than that with sand columns only.展开更多
基金supported by Program for New Century Excellent Talents in University of China (Grant No.NCET-12-0941)the Fundamental Research Funds for the Central Universities of China (Grant No.A0920502051206-3)
文摘With the development of high-speed railway in China, composite foundation with rigid piles has become a stamdard solution of meeting the high requirements of stability and post-construction settlement of embankment on soft subgrade. Among several im- provement pattems, plain concrete piles have been extensively used to treat soft ground supported embankment. To investigate the deformation and failure modes of unimproved soft ground and soft ground reinforced by sub-embankment plain concrete piles, and to learn the influences of track and vehicle load, the effect of pile spacing, as well as the compression moduli of soil layers and upper load condition on the failure modes, a series of centrifuge model tests were performed. Test results indicate that the dis- placement of unimproved soft ground under the embankment increases continuously as embankment, track and train loading, and slip circle failure takes place. The deformation law of soft ground reinforced by sub-embankment plain concrete piles depends on pile spacing, compression modulus of the soft ground, and loading conditions. It was also found that plain concrete piles show displacement and failure patterns depending on its location, compression modulus of soft soil around the pile, and loading condi- tions. Furthermore, the evaluation of improved ground stability as well as the model test procedure is also presented.
基金Project (No.50478090) supported by the National Natural Science Foundation of China
文摘A physical model facility was designed,built,and setup for conducting model tests on a composite foundation in a soil ground.The model tests were carried out on a composite foundation with different combinations of vertical reinforcement elements in the same soil ground.Via the analysis of the collected data the characteristics of the composite foundation with different reinforcing elements were obtained,including the characteristics of load-settlement curves,column stresses,stresses of the inter-column soil,pile-soil stress ratio,and load-sharing ratios of columns and soil.Results from the model tests reveal the mechanism of a composite foundation with different reinforcing elements quantitatively.It is concluded that both a composite foundation with a combination of steel pipe pile and sand column and that with a combination of concrete pile and lime column have a higher bearing capacity than the composite foundation with only sand columns with the same conditions of soil ground and loading.A composite foundation with lime column and sand column embodies no much better performance than that with sand columns only.
