Field study on swelling-shrinkage response of an expansive soil foundation under high-speed railway embankment loads |
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Authors: | Guanlu Jiang Weizhi Chen Xianfeng Liu Shengyang Yuan Lijun Wu Chonglei Zhang |
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Affiliation: | 1. Key Laboratory of High-speed Railway Engineering of Ministry of Education, School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China;2. China Railway Eryuan Engineering Group Co., Ltd., Chengdu, China;3. Priority Research Centre for Geotechnical and Materials Modelling, Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan, NSW, Australia;4. College of Environment and Civil Engineering, Chengdu University of Technology, Chengdu 610031, China;5. Key Laboratory of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China |
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Abstract: | This paper presents a comprehensive field investigation of the swelling-shrinkage behavior of an expansive soil ground under high-speed railway embankment loads. In this study, a test site close to the Kunming-Nanning high-speed railway (KNHR) was chosen for the construction of four full-scale field test facilities for artificially soaking the expansive soil ground. Three of the facilities consist of embankments of three different heights, while the fourth facility is for a series of plate load swelling tests. All the test embankments were fully instrumented to monitor the ground deformation and the changes in volumetric water content profiles of the foundations. The full-scale field tests were complemented by a detailed site investigation comprised of cone penetration tests (CPTs), standard penetration tests (SPTs) and a comprehensive laboratory characterization of intact expansive soil samples retrieved from the test site. The results obtained from the laboratory and field tests show that the swelling behavior of the expansive soil ground mainly depends on the embankment load. By properly designing the embankment height and considering the maximum swelling pressure the expansive ground could induce, the heave of the embankment could be controlled efficiently. The measured displacements at the ground surface are well correlated with the evolution of measured volumetric water contents within a ground depth of around 4.5?m. The majority of these displacements occurred when the ground was approaching saturation along both wetting and drying paths. Finally, a simple method based on one-dimensional test results was proposed, and a good performance was shown in predicting the heave or settlement of embankments over an expansive soil ground upon wetting and drying. |
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Keywords: | High-speed railway Low subgrade Expansive soil foundation Swell-shrinking behavior Field test Unsaturated soil |
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