Effect of cushion and cover on moisture distribution in clay embankments in southern China

Abstract

To achieve durability of the embankment in southern China, a method to control the change of moisture content with the cushion and cover was proposed. A finite element model of cushion and cover considering different materials and thicknesses for a typical embankment was built, and 20 numerical analyses of transient seepage in the embankment were simulated. The results show that the sand cushion effectively blocks the effect of groundwater capillary rise and the minimum thickness of the sand cushion is 75 cm without considering the atmospheric environment. With the combination of sand cushion and clay cover, as the thickness of the clay cover increases, the duration time of the moisture content from the initial to relative equilibrium state increases, but the equilibrium moisture content is the same as that of the original embankment. Besides, with the combination of the sand cushion and sand cover, the moisture content inside the embankment remains the same, which is consistent with the optimum moisture content during construction. The combination of 75 cm sand cushion and 30 cm sand cover is a very effective method to block groundwater and atmospheric environment, and achieve the control of the humidity stability of the embankment in southern China.

References

[1] ZhangJ H, DingL, LiF, PengJ H. Recycled aggregates from construction and demolition wastes as alternative filling materials for highway subgrades in China [J]. Journal of Cleaner Production, 2020, 255: 120223

[2] PengJ H, ZhangJ H, LiJ, YaoY S, ZhangA S. Modeling humidity and stress-dependent subgrade soils in flexible pavements [J]. Computers and Geotechnics, 2020, 120103413

[3] YangK H, ThuoJ N A A, HuynhV D A, NguyenT S, PortelinhaF H M. Numerical evaluation of reinforced slopes with various backfill-reinforcement-drainage systems subject to rainfall infiltration [J]. Computers and Geotechnics, 2018, 9625-39

[4] VahedifardF, MortezaeiK, LeshchinskyB A, LeshchinskyD, LuN. Role of suction stress on service state behavior of geosynthetic-reinforced soil structures [J]. Transportation Geotechnics, 2016, 8: 45-56

[5] ZengL, XiaoL Y, ZhangJ H, FuH Y. The role of nanotechnology in subgrade and pavement engineering: A review [J]. Journal of Nanoscience and Nanotechnology, 2020, 20: 4607-4618

[6] LiJ H, DuL, ChenR, ZhangL M. Numerical investigation of the performance of covers with capillary barrier effects in South China [J]. Computers and Geotechnics, 2013, 48: 304-315

[7] YaoY S, ZhengJ L, ChenZ S, ZhangJ H, LiY. Field measurements and numerical simulations of temperature and moisture in highway engineering using a frequency domain reflectometry sensor [J]. Sensors, 2016, 16(6): 857

[8] HatamiK, EsmailiD, ChanE C, MillerG A. Moisture reduction factors for shear strength of unsaturated reinforced embankments [J]. International Journal of Geomechanics, 2016, 166D4016001

[9] ZHANG J H, PENG J H, ZHANG A S, LI J. Prediction of permanent deformation for subgrade soils under traffic loading in southern China [J]. International Journal of Pavement Engineering, 2020. DOI: https://doi.org/10.1080/10298436.2020.1765244.

[10] ZHANG J H, PENG J H, ZENG L, LI J, LI F. Rapid estimation of resilient modulus of subgrade soils using performance-related soil properties [J]. International Journal of Pavement Engineering, 2019. DOI: https://doi.org/10.1080/10298436.2019.1643022.

[11] AbuhajarO, ElN H, NewsonT. Numerical modeling of soil and surface foundation pressure effects on buried box culvert behavior [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2016, 1421204016072

[12] WeiH W, WuY Z, YuZ H. Design parameter optimization of beam foundation on soft soil layer with nonlinear finite element [J]. Journal of Central South University, 2012, 1961753-1763

[13] GasmoJ M, RahardjoH, LeongE C. Infiltration effects on stability of a residual soil slope [J]. Computers and Geotechnics, 2000, 26(2): 145-165

[14] LiuZ, YuX, WanL. Capillary rise method for the measurement of the contact angle of soils [J]. Acta Geotechnica, 2016, 11(1): 21-35

[15] YanC G, WanQ, XuY, XieY L, YinP J. Experimental study of barrier effect on moisture movement and mechanical behaviors of loess soil [J]. Engineering Geology, 2018, 240: 1-9

[16] HellwigD H R. Evaporation of water from sand: 4. The influence of thedepth of the water-table and the particle size distribution of the sand [J]. Journal of Hydrology, 1973, 18(34): 317-327

[17] ShahN, NachabeM, RossM. Extinction depth and evapotranspiration from ground water under selected land covers [J]. Ground Water, 2007, 45(3): 329-338

[18] LIU J, YAO H L, CHEN P, LU Z, LUO X W. Theoretical analysis and experimental study of subgrade moisture variation and underground antidrainage technique under groundwater fluctuations [J]. Journal of Applied Mathematics, 2013(5): 703251. DOI: https://doi.org/10.1155/2013/703251.

[19] ZhangL M, KeY Q. Combinations of soil materials for granular capillary barriers for minimizing rainfall infiltration and gas emission [J]. Canadian Geotechnical Journal, 2017, 54(11): 1580-1591

[20] LewisT W, PivonkaP, FityusS G, SmithD W. Parametric sensitivity analysis of coupled mechanical consolidation and contaminant transport through clay barriers [J]. Computers and Geotechnics, 2009, 36(1): 31-40

[21] LiuX, ShengK, HuaJ H, HongB N, ZhuJ J. Utilization of high liquid limit soil as subgrade materials with pack-and-cover method in road embankment construction [J]. International Journal of Civil Engineering, 2015, 13(3b): 167-174

[22] GeeG W, WardA L, MeyerP D. Method to estimate water storage capacity of capillary barriers [J]. Journal of Geotechnical and Geoenvironmental Engineering, 1998, 125(10): 297-302

[23] NicholsonR V, GillhamR W, CherryJ A, ReardonE J. Reduction of acid generation in mine tailings through the use of moisture-retaining cover layers as oxygen barriers [J]. Canadian Geotechnical Journal, 1989, 27(3): 402-403

[24] LAI J X, LIU H Q, QIU J L, CHEN J X. Settlement analysis of saturated tailings dam treated by CFG pile composite foundation [J]. Advances in Materials Science and Engineering, 2016: 7383762. DOI: https://doi.org/10.1155/2016/7383762.

[25] ZhangW J, SunC, QiuQ W. Characterizing of a capillary barrier evapotranspirative cover under high precipitation conditions [J]. Environmental Earth Sciences, 2016, 75(6): 513

[26] YangH, RahardjoH, LeongE C, FredlundD G. A study of infiltration on three sand capillary barriers [J]. Canadian Geotechnical Journal, 2004, 414629-643

[27] HarnasF R, RahardjoH, LeongE C, WangJ Y. Experimental study on dual capillary barrier using recycled asphalt pavement materials [J]. Canadian Geotechnical Journal, 2014, 51(10): 1165-1177

[28] ColemanJ D, RussamK. The effect of climatic factors on subgrade moisture conditions [J]. Géotechnique, 1961, 11(1): 22-28

[29] ChandlerN, PalsonJ, BurnsT. Capillary rise experiment to assess effectiveness of an enzyme soil stabilizer [J]. Canadian Geotechnical Journal, 2017, 54(10): 1509-1517

[30] PredelusD, CoutinhoA P, LassabatereL, BienL B, WiniarskiT, Angulo-JaramilloR. Combined effect of capillary barrier and layered slope on water, solute and nanoparticle transfer in an unsaturated soil at lysimeter scale [J]. Journal of Contaminant Hydrology, 2015, 181: 69-81

[31] BradshawS L, BensonC H, ScaliaJ. Hydration and cation exchange during subgrade hydration and effect on hydraulic conductivity of geosynthetic clay liners [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2013, 139(4): 526-538

[32] ZHANG J H, PENG J H, LIU W Z, LU W H. Predicting resilient modulus of fine-grained subgrade soils considering relative compaction and matric suction [J]. Road Materials and Pavement Design, 2019: 1–13. DOI: https://doi.org/10.1080/14680629.2019.1651756.