Study of Infiltration into Partially Saturated Clay Soil Railway Embankment
This paper will involve using commercial software Vadose/W to model this process and using a variable flow boundary at the ground surface to represent infiltration by rainfall into partially saturated clay soil railway embankment. To investigate the influ
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Introduction The infiltration of rainfall into partially saturated clay soil could change the distribution of pore-water pressure significantly, which could influence the soil shear strength and the stability of clay railway embankment. The process of rainfall infiltration have been previously studied by many researchers (Lumb [7]; Leach and Herbert [6]; Anderson and Pope [1]; Lam et al [5]). However, it is difficult to predict the distribution of pore-water pressure in the partially saturated clay soil accurately, since the complex ground conditions. Vadose/W, a commercial FEA software can simulate the whole process of rainfall infiltration into partially saturated clay soil and estimate the distribution of pore-water pressure in the vadose zone [4]. The aim of this paper is to model and analyze the process of rainfall infiltration with different flow boundary condition. The influences on the infiltration caused by variable rainfall and soil water properties will be investigated, in order to find the relationship between them.
T. Li (&) China Academy of Railway Sciences, Beijing 100081, China e-mail: [email protected] Q. Zhang D. Cai J. Yao F. Chen China Academy of Railway Sciences Railway Engineering Research Institute, Beijing 100081, China e-mail: [email protected] D. Cai e-mail: [email protected] J. Yao e-mail: [email protected] F. Chen e-mail: [email protected] © Springer Nature Singapore Pte. Ltd. and Zhejiang University Press 2018 X. Bian et al. (eds.), Environmental Vibrations and Transportation Geodynamics, DOI 10.1007/978-981-10-4508-0_44
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Numerical Modelling and Parameter Selection Based on the research from Briggs et al. [2, 3] and some currently existing field data, the transient rainfall infiltration model will be made in this paper, the research will focus on the analysis of rainfall infiltration into partially saturated clay soil in the winter period.
Time Duration and Time Segment Both short-term and long-term analysis will be considered in this paper with comparison and discussion between them. For long-term analysis each time segment has been set as 6 days with overall 30 time steps for the winter period. For short term analysis, the time duration has been set as 30 days, each time segment is 1 day with 30 time steps.
Material Properties There are four types of clay soil material with different saturated hydraulic conductivity will be used in the FEA model. Table 1 shows the properties of all clay soil materials which will be used in this paper, based on investigation of currently existing field records. Also, each clay soil material was assumed isotropic.
One-Dimensional Soil Column Model in Vadose/W The one-dimensional FEA model will be used in this paper, since both efficiency and workability consideration [2]. Each column is 9 m deep and 1 m width, and divided into three layers, each layer will have its own value of saturated permeability. The water table was assumed to be located at 7 m deep from the ground surface, and the pore-water pressure was set as initially hydrostatic.
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