Abstract
Due to the perennial influence by west wind climate, the loess in Ili, China, is obviously different from that in the loess plateau of the monsoon area, showing the characteristics of large collapsible deformation and high soluble salt content. During the operation of hydraulic structures such as canals, the distribution of soluble salt content in the surrounding unsaturated soil is uneven due to the movement of water, which affects the deformation and safety of construction projects. In order to reveal the mechanical characteristics of the undisturbed unsaturated Ili loess with different soluble salt contents, the net mean stress increase and decrease tests of controlling suction, the suction increase and decrease tests of controlling net mean stress, and the consolidation shear tests of controlling net confining pressure and suction were carried out under different soluble salt contents, to explore the influence of soluble salt content on the characteristics of deformation, yield, strength, and water content. The results show that the soluble salt content has a critical value to improve the cementation between particles, and there exist maximum yield values of net mean stress, yield shear stresses, and shear strength with the soluble salt content of 14–20 g/kg, corresponding to the maximum structural strength and elastic region. The rebound coefficient increases with the increase of the initial rebound pressure. With the increase of soluble salt content, the water discharge of the consolidation stage and the compressibility index are decreasing. The degree of saturation is more affected by the soluble salt content in the transition zone. For a certain soluble salt content, the initial and subsequent yield curves are approximately assumed to be ellipses that are symmetrical to the initial stress state line, and the hardening effect produced by stress and suction is isotropic. The above results verify the LC and SI yield curves of unsaturated Ili loess and reveal the shape and hardening law of yield curves in the p-q plane, which offer model parameters for the establishment of the humidification deformation constitutive model and provide reference for the prediction of unsaturated mechanical and hydraulic properties in the Ili area.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- a :
-
Corrected intercept of the critical state line (unit: kPa)
- c :
-
Corrected cohesion (unit: kPa)
- CSL:
-
Critical state line
- e and e 0 :
-
Any void ratio and initial void ratio, respectively
- G s :
-
Specific gravity
- I p :
-
Plasticity index
- k 0 :
-
Coefficient of earth pressure at rest
- M :
-
The slope of the critical state line of saturated soil
- p, p a, p y, p f, and p 0 :
-
Net mean stress, atmospheric pressure, shear yield net mean stress, shear failure net mean stress, and yield net mean stress, respectively (unit: kPa)
- q, q y , q f, and q/p :
-
Deviator stress, shear yield deviator stress, shear failure deviator stress, and stress ratio, respectively (unit: kPa)
- s and s y :
-
Any matric suction and yield suction, respectively (unit: kPa)
- S r :
-
Degree of saturation (unit: %)
- u a and u w :
-
Pore air pressure and pore water pressure, respectively (unit: kPa)
- V 0 and ΔV w :
-
Initial volume and volume change of water, respectively (unit: cm3)
- w, w 0, w l, and w p :
-
Any water content, initial water content, liquid limit, and plastic limit, respectively (unit: %)
- β(s):
-
The slope of the w-p curve
- ε v, ε vp, ε w, and ε 1 :
-
Volume strain, plastic volume strain, volume strain of water, and axial strain, respectively (unit: %)
- θ :
-
Soluble salt content (unit: g/kg)
- κ 100, κ 300, and κ s :
-
Rebound coefficient when the starting rebound pressure is 100 kPa and 300 kPa and rebound coefficient changed by suction in the elastic domain, respectively
- λ s, λ ( s ), and λ w(s):
-
Compression coefficient increased by suction, compressibility index, and the slope of the εw-p curve, respectively
- ρ d :
-
Dry density (unit: g/cm3)
- σ 1, σ 2, σ 3, and σ 3 − u a :
-
Large, medium, and small principal stresses and net confining pressures, respectively (unit: kPa)
- φ, φ′, φ u, and φ b :
-
Any internal friction angle, effective internal friction angle, internal friction angle of unsaturated soil, and internal friction angle of suction, respectively (unit: °
References
Alonso EE, Gens A, Josa A (1990) A constitutive model for partially saturated soils. Geotechnique 40(3):405–430. https://doi.org/10.1680/geot.1990.40.3.405
Atashgahi1 S, Tabarsa A, Shahryari A, Hosseini SS (2020) Effect of carbonate precipitating bacteria on strength and hydraulic characteristics of loess soil. B Eng Geol Environ. https://doi.org/10.1007/s10064-020-01857-0
Chen R, Huang JW, Zhou C, Ping Y, Chen ZK (2021) A new simple and low-cost air permeameter for unsaturated soils. Soil & Tillage Research 213:105083. https://doi.org/10.1016/j.still.2021.105083
Chen CL, Zhang DF, Dong YZ, Chen H, Yu DB, Xue JX (2014) Suction and mechanical behaviours of unsaturated intact loess from constant water content triaxial tests. Chinese J Geotech Eng 36(7):1195–1202. https://doi.org/10.11779/CJGE201407002
Chen ZH (1999) Deformation, strength, yield and moisture change of a remolded unsaturated loess. Chinese J Geotech Eng 21(1):82–90
Chen ZH, Sun SG, Fang XW, Zhu YQ, Xie Y (2007) Development and application of multi-function triaxial apparatus for soil. J Logist Eng Univ 23(4):1–5
Choudhury C, Bharat TV (2018) Wetting-induced collapse behavior of kaolinite: influence of fabric and inundation pressure. Can Geotech J 55:956–967. https://doi.org/10.1139/cgj-2017-0297
Cui YJ, Delage P (1996) Yielding and plastic behaviour of an unsaturated compacted. Geotechnique 46(2):291–311. https://doi.org/10.1680/geot.1996.46.2.291
Das AP, Thyagaraj T (2017) Effect of pore fluid on compressibility and collapse of clayey sand. Environ Geotech 4:432–443. https://doi.org/10.1680/jenge.15.00073
Di Maio C, Santoli L, Schiavone P (2004) Volume change behaviour of clays: the influence of mineral composition, pore fluid composition and stress state. Mech Mater 36:435–451
Dutta J, Mishra AK (2016) Consolidation behaviour of bentonites in the presence of salt solutions. Appl Clay Sci 120:61–69. https://doi.org/10.1016/S0167-6636(03)00070-X
Gao Y, Sun DA, Zhu ZC, Xu YF (2019) Hydromechanical behavior of unsaturated soil with different initial densities over a wide suction range. Acta Geotech 14:417–428. https://doi.org/10.1007/s11440-018-0662-5
Gajo A, Loret B (2007) The mechanics of active clays circulated by salts, acids and bases. Journal of the Mechanics & Physics of Solids. 55(8):1762-1801
Garakani AA, Haeri SM, Cherati DY, Givi FA, Tadi MK, Hashemi AH, Chiti N, Qahremani F (2018) Effect of road salts on the hydro-mechanical behavior of unsaturated collapsible soils. Transp Geotech 17:77–90. https://doi.org/10.1016/j.trgeo.2018.09.005
Graham J, Noonan ML, Lew KV (1983) Yield states and stress-strain relationships in a natural plastic clay. Can Geotech J 20(3):502–516. https://doi.org/10.1139/t84-063
Han Y, Wang Q, Kong YY, Cheng SK, Wang JQ, Zhang XD, Wang N (2018) Experiments on the initial freezing point of dispersive saline soil. Catena 171:681–690. https://doi.org/10.1016/j.catena.2018.07.046
Ismael NF (1993) Laboratory and field leaching tests on coastal salt-bearing soils. Journal of Geotech Eng 119(3):453–470. https://doi.org/10.1061/(ASCE)0733-9410(1993)119:3(453)
Mu QY, Zhou C, Ng CWW (2020) Compression and wetting induced volumetric behavior of loess: Macro-and micro-investigations. Transportation Geotechnics, 23, 100345
Ravi K, Rao SM (2013) Influence of infiltration of sodium chloride solutions on SWCC of compacted bentonite-sand specimens. Geotech Geol Eng 31:1291–1303. https://doi.org/10.1007/s10706-013-9650-6
Shariatmadari N, Salami M, Fard MK (2011) Effect of inorganic salt solutions on some geotechnical properties of soil-bentonite mixtures as barriers. Int J Civ Eng 9(2):103–110
Song MM, Zeng LL, Hong ZS (2017) Pore fluid salinity effects on physicochemical-compressive behaviour of reconstituted marine clays. Appl Clay Sci 146:270–277. https://doi.org/10.1016/j.clay.2017.06.015
Sun DA, Zhang J, Gao Y, Sheng D (2016) Influence of suction history on hydraulic and stress-strain behavior of unsaturated soils. Int J Geomech 16(6):270–277. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000602
Tabiatnejad B, Siddiqua S, Siemens G (2016) Impact of pore fluid salinity on the mechanical behavior of unsaturated bentonite-sand mixture. Environ Earth Sci 75:1434. https://doi.org/10.1007/s12665-016-6246-5
Tang H, Duan Z, Wang DP, Dang Q (2020) Experimental investigation of creep behavior of loess under different moisture contents. B Eng Geol Environ 79:411–422. https://doi.org/10.1007/s10064-019-01545-8
Wang SH, Wang QZ, Qi JL, Liu FY (2018) Experimental study on freezing point of saline soft clay after freeze-thaw cycling. Geomech Eng 15(4):997–1004. https://doi.org/10.12989/gae.2018.15.4.997
Wang SH, Wang QZ, Xu J, Ding JL, Qi JL, Yang YG, Liu FY (2019a) Thaw consolidation behavior of frozen soft clay with calcium chloride. Geomech Eng 18(2):189–203. https://doi.org/10.12989/gae.2019.18.2.189
Wang SH, Ding JL, Xu J, Ren, JW, Yang,YG (2019b) Shear strength behavior of coarse-grained saline soils after freeze-thaw. KSCE J Civ Eng 23(6):2437–2452. https://doi.org/101007/s10064-020-01855-2
Wang YG, Zhang AJ, Ren WY, Niu LS (2019) Study on the soil water characteristic curve and its fitting model of Ili loess with high level of soluble salts. J Hydrol 578:124067. https://doi.org/10.1016/j.jhydrol.2019.124067
Wang QZ, Qi JL, Wang SH, Xu J, Yang YG (2020) Effect of freeze-thaw on freezing point of a saline loess. Cold Reg Sci Technol 170:102922. https://doi.org/10.1016/j.coldregions.2019.102922
Witteveen P, Ferrari A, Laloui L (2013) An experimental and constitutive investigation on the chemo-mechanical behaviour of a clay. Geotechnique 63(3):244–255. https://doi.org/10.1680/geot.SIP13.P.027
Xu J, Liu H, Zhao XK (2017) Study on the strength and deformation property of frozen silty sand with NaCl under tri-axial compression condition. Cold Reg Sci Technol 137:7–16. https://doi.org/10.1016/j.coldregions.2017.01.008
Xu J, Li YF, Lan W, Wang SH (2019a) Shear strength and damage mechanism of saline intact loess after freeze-thaw cycling. Cold Reg Sci Technol 164:102779. https://doi.org/10.1016/j.coldregions.2019.05.005
Xu J, Li YF, Wang SH, Wang QZ, Ding JL (2019b) Shear strength and mesoscopic character of undisturbed loess with sodium sulfate after dry-wet cycling. B Eng Geol Environ 79:1523–1541. https://doi.org/10.1007/s10064-019-01646-4
Xu YF, Xiang GS, Jiang H, Chen T, Chu FF (2014) Role of osmotic suction in volume change of clays in salt solution. Appl Clay Sci 101:354–361. https://doi.org/10.1016/j.clay.2014.09.006
Ye WM, Zhang F, Chen B, Chen YG, Wang Q, Cui YJ (2014) Effects of salt solutions on the hydro-mechanical behavior of compacted GMZ01 Bentonite. Environ Earth Sci 72:2621–2630. https://doi.org/10.1007/s12665-014-3169-x
Yin J, Hu MM, Xu GZ, Han WX, Miao YH (2019) Effect of salinity on rheological and strength properties of cement-stabilized clay minerals. Mar Georesour Geotec 38:611–620.
Zhang FY, Wang GH, Kamai T, Chen WW, Zhang DX, Yang J (2013) Undrained shear behavior of loess saturated with different concentrations of sodium chloride solution. Eng Geol 155:69–79. https://doi.org/10.1016/j.enggeo.2012.12.018
Zhang M, Zhang HY, Jia LY, Cui Sl (2012) Salt content impact on the unsaturated property of bentonite–sand buffer backfilling materials. Nucl Eng Des 250:35–41. https://doi.org/10.1016/j.nucengdes.2012.05.012
Zhang AJ, Xing YC, Hu XL, Wang HT, Guo MX, Zhang B, Gao YP (2016b) Influence factors of strong self-weight collapsibility of Ili loess. Chinese Journal of Geotechnical Engineering 38 (Suppl2):117–122. https://doi.org/10.11779/CJGE2016S2019
Zhang F, Ye WM, Chen YG, Chen B, Cui YJ (2016a) Influences of salt solution concentration and vertical stress during saturation on the volume change behavior of compacted GMZ01 bentonite. Eng Geol 207:48–55. https://doi.org/10.1016/j.enggeo.2016.04.010
Acknowledgements
The authors are grateful to Minxia Guo, Haijun Hu, WuqingYan, and Shunxiang Kang of Northwest A&F University for sample preparation and laboratory operations.
Funding
This study received financial support from the State Key Research and Development Plan of China (Grant No. 2017YFC0405103), National Natural Science Foundation of China (Grant No. 51978572), and Key Research and Development Projects in Shaanxi Province of China (Grant No. 2017ZDXM-SF-074).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Niu, L., Ren, W., Zhang, A. et al. Experimental study on the influence of soluble salt content on unsaturated mechanical characteristics of undisturbed Ili loess. Bull Eng Geol Environ 80, 6689–6704 (2021). https://doi.org/10.1007/s10064-021-02340-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10064-021-02340-0