Mechanical Properties of Cement-Improved Loess Fillerfor Intercity Railway

Abstract

Abstract: In order to reveal the change law of the mechanical properties of the cement-improved loess subgrade fillers on the intercity railway, the influence of cement dosage, compaction coefficient, and curing age on the mechanical properties of the cement-improved loess subgrade fillers were studied through laboratory tests, and the dosage of the improved loess filler cement was optimized. The research shows that the compression strength of 2% (mass fraction, the same below) cement dosage improved loess test piece at 7 d under the compaction coefficient of 0.92 meets the standard value, but the test piece is damaged after soaking; the improved loess sample with cement dosage ≥3% is complete after soaking, and the cement dosage increases by 1%. 28 d compressive strength and splitting strength increase at least 12.3% and 17.0% on average, respectively. The compaction coefficient increases by 0.01, the compressive strength and splitting strength of the improved loess increase by at least 5.4% and 8.0%. The strength growth rate is significantly higher than that of the later stage. The compressive strength and splitting strength of the improved loess specimen with cement dosage ≥3% were about 61% and 45% of their corresponding ultimate strengths, respectively. In order to ensure the strength and bearing capacity of the subgrade, the cement dosage of the embankment below the foundation bed is recommended to be 3% and the compaction coefficient is 0.95. The cement dosage of the embankment to the bottom of the foundation bed is recommended to be 4% and the compaction coefficient is 0.98.

Key words: railway engineering, cement-improved loess, subgrade filler, mechanical property, engineering application

CLC Number:

TU411

JIANG Yingjun, ZHANG Wei, LI Qilong, QIAO Huaiyu. Mechanical Properties of Cement-Improved Loess Fillerfor Intercity Railway[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(7): 2409-2417.

References

[1] 倪涛,裴向军,范明明,等.SJP水泥改良土浆的基本物理性能试验研究[J].硅酸盐通报,2019,38(8):2637-2641.
NI T, PEI X J, FAN M M, et al. Experimental study on basic physical properties of SJP cement improved soil slurry[J]. Bulletin of the Chinese Ceramic Society, 2019, 38(8): 2637-2641 (in Chinese).
[2] 江涛.银西高铁甘宁段水泥改良黄土路基冻胀规律及冻胀防治效果评价[J/OL].铁道标准设计:1-8[2021-03-07].https://doi.org/10.13238/j.issn.1004-2954.202009210002.
JIANG T. The frost heave law of cement-improved loess as filling material for subgrade and evaluation of anti-frost engineering measurements in gansu-ningxia section of Yinchuan-Xi’an high-speed railway[J/OL].Railway Standard Design: 1-8 [2021-03-07]. https://doi.org/10.13238/j.issn.1004-2954.202009210002 (in Chinese).
[3] 吴文飞,张纪阳,何锐,等.固化剂改良水泥稳定黄土强度及水稳性研究[J].硅酸盐通报,2016,35(7):2159-2165.
WU W F, ZHANG J Y, HE R, et al. Firming agent to improve strength and water stability of stabilized loess with cement[J]. Bulletin of the Chinese Ceramic Society, 2016, 35(7): 2159-2165 (in Chinese).
[4] 张沛云,马学宁,李善珍,等.高速铁路水泥改良黄土路基长期动力稳定性评价[J].振动与冲击,2019,38(11):80-87.
ZHANG P Y, MA X N, LI S Z, et al. Long-term dynamic stability evaluation for cement-improved loess subgrade of high speed railway[J]. Journal of Vibration and Shock, 2019, 38(11): 80-87 (in Chinese).
[5] 苏毅.高速铁路路基黄土填料改良后的工程特性研究[J].铁道建筑,2017,57(7):100-103.
SU Y. Engineering characteristics of the improved loess filling material for high speed railway[J]. Railway Engineering, 2017, 57(7): 100-103 (in Chinese).
[6] 吴凤明.宝兰湿陷性黄土工程特性试验研究[D].石家庄:石家庄铁道大学,2015.
WU F M. Engineering properties experimental study Bao Lan of collapsible loess[D]. Shijiazhuang: Shijiazhuang Tiedao University, 2015 (in Chinese).
[7] 万志辉,戴国亮,龚维明,等.海水侵蚀环境对钙质砂水泥土强度影响及微观结构研究[J].岩土工程学报,2020,42(s1):65-69.
WAN Z H, DAI G L, GONG W M, et al. Strength and microstructure of calcareous sand-cemented soil under seawater erosion environment[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(s1): 65-69 (in Chinese).
[8] 鹿群,郭少龙,王闵闵,等.纤维水泥土力学性能的试验研究[J].岩土力学,2016,37(s2):421-426.
LU Q, GUO S L, WANG M M, et al. Experimental study of mechanical properties of fiber cement soil[J]. Rock and Soil Mechanics, 2016, 37(s2): 421-426 (in Chinese).
[9] 陈中学,李文广,任涛,等.水泥土无侧限抗压强度试验分析[J].公路交通技术,2016,32(5):4-8.
CHEN Z X, LI W G, REN T, et al. Unconfined compressive strength test analysis for cement soil[J]. Technology of Highway and Transport, 2016, 32(5): 4-8 (in Chinese).
[10] 阮锦楼,阮波,阳军生,等.粉质粘土水泥土无侧限抗压强度试验研究[J].铁道科学与工程学报,2009,6(3):56-60.
RUAN J L, RUAN B, YANG J S, et al. Experimental study on cement-soil unconfined compressive strength of silty clay[J]. Journal of Railway Science and Engineering, 2009, 6(3): 56-60 (in Chinese).
[11] 崔永成,崔自治,周健,等.银川地区粉煤灰水泥土的力学特性试验研究[J].工业建筑,2012,42(7):105-109+151.
CUI Y C, CUI Z Z, ZHOU J, et al. Research on mechanical properties of fly ash cement soil in Yinchan[J]. Industrial Construction, 2012, 42(7): 105-109+151 (in Chinese).
[12] 马晓宇,李平.复合矿粉水泥土的无侧限抗压强度试验[J].中国科技论文,2014,9(5):590-593.
MA X Y, LI P. Unconfined compressive strength test of composite mineral powder soil-cement[J]. China Sciencepaper, 2014, 9(5): 590-593 (in Chinese).
[13] 徐丽娜,牛雷,张婷,等.玄武岩纤维和水泥加固河床淤泥土无侧限抗压强度的试验研究[J].工业建筑,2020,50(2):109-112.
XU L N, NIU L, ZHANG T, et al. Experimental researth on the unconfined compression strength characteristics of basalt fiber and cement stabilized riverbed silt[J]. Industrial Construction, 2020, 50(2): 109-112 (in Chinese).
[14] LORENZO G A, BERGADO D T. Fundamental parameters of cement-admixed clay: new approach[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2004, 130(10): 1042-1050.
[15] 蒋应军,李明杰,张俊杰,等.水泥稳定碎石强度影响因素[J].长安大学学报(自然科学版),2010,30(4):1-7.
JIANG Y J, LI M J, ZHANG J J, et al. Influence factors of strength properties of cement stabilization of crushed aggregate[J]. Journal of Chang’an University (Natural Science Edition), 2010, 30(4): 1-7 (in Chinese).