In order to specific process of changing the physical, chemical and structural characteristics of soil by thermal reinforcement, and then affecting the engineering properties such as strength and water stability was clarified. The influence laws and action mechanisms of high temperature from 100℃ to 900℃ on the unconfined compressive strength and water-stability of compacted Yangling loess were discussed by four tests that are unconfined compressive strength, X-ray diffraction, mercury intrusion porosimetry and scanning electron microscopy. The results show that the unconfined compressive strength of samples treated after 900 ℃ was 1.15~5.26 MPa higher than that after 100 ℃; The samples had great water-stability when treatment temperature was not less than 500 ℃; The mineral contents of illite, montmorillonite, calcite and quartz changed under 500~900 ℃; The quantity of micro-pores (0.01 μm<d<0.1 μm), super micro-pores (d<0.01 μm) and pore fractal dimension of samples obviously decreased under 700~900 ℃; There are some high-temperature melting phenomena that promote the formation of some "dense structures" in soil particles; The soil particles are subjected to movement and rearrangement and forms some new compounds under the action of high temperature, which improves the compressive strength and water stability of samples. The research results can provide data and mechanism support for the application of thermal reinforcement method.
Zhang Lu
,
Ni Xiaoyi
,
Fan Henghui
,
Gao Ce
,
Du Yuhang
. Experimental Study on the Effect of Thermal Reinforcement on the Engineering Properties of Compacted Loess[J]. Chinese Journal of Underground Space and Engineering, 2024
, 20(S1)
: 77
-83
.
DOI: 10.20174/j.JUSE.2024.S1.10
[1] 樊恒辉, 倪晓逸, 孟敏强, 等. 土体热加固方法的研究进展[J]. 水利与建筑工程学报, 2021, 19(5): 1-7.
[2] 钱鸿缙, 王继唐, 罗宇生, 等. 湿陷性黄土地基[M]. 北京: 中国建筑工业出版社, 1985: 396-402.
[3] 舒勇. 土体热加固工程实例[A] // 龚晓南编. 第三届全国地基处理学术研讨会论文集[C]. 杭州: 浙江大学出版社, 1992: 506-509.
[4] 裴章勤, 刘卫东. 湿陷性黄土地基处理[M]. 北京: 中国铁道出版社, 1992: 141-167.
[5] Л.B.冈恰罗娃.孙全德译. 黄土类土的超高频电磁场热加固法[J]. 路基工程, 1990(5): 82-86.
[6] 谈鹏燕, 许光详. 湿陷性黄土的电热丝热加固法探讨[J]. 路基工程, 2007(5): 113-114.
[7] Abu-zreig M M, Al-akhras N M, Attom M F. Influence of heat treatment on the behavior of clayey soils[J]. Applied Clay Science, 2001, 20(3): 129-135.
[8] Towhata I, Kuntiwattanakul P, Kobayashi H. A preliminary study on heating of clays to examine possible effects of temperature on soil-mechanical properties[J]. Journal of the Japanese Society of Soil Mechanics and Foundation Engineering, 2008, 33(4): 184-190.
[9] Joshi R C, Achari G, Horsfield D, et al. Effect of heat treatment on strength of clays[J]. Journal of Geotechnical Engineering, 1994, 12(6): 1080-1088.
[10] Yilmaz G. The effects of temperature on the characteristics of kaolinite and bentonite[J]. Scientific Research and Essays, 2011, 6(9): 1928-1939.
[11] 张栋. 大连东港地区淤泥质土高温烧结处理研究[D]. 大连: 大连海事大学, 2016.
[12] 张玉良, 孙强, 李进学, 等. 高温焙烧后黏土孔隙与力学特征研究[J]. 岩石力学与工程学报, 2016, 34(7): 1480-1488.
[13] Sun Q, Zhang W, Zhang Y, et al. Variations of strength, resistivity and thermal parameters of clay after high temperature treatment [J]. ActaGeophysica, 2016, 64(6): 2077-2091.
[14] 安家驹, 包文滁, 王伯英, 等. 实用精细化工辞典[M]. 北京: 中国轻工业出版社, 2000.
[15] Lee S, Kim Y J, Moon H S. Phase transformation sequence from kaolinite to mullite investigated by an energy-filtering transmission electron microscope[J]. Journal of the American Ceramic Society, 1999, 82(10): 2841-2848.
[16] 蔡进功. 泥质沉积物和泥岩中的有机粘土复合体[D]. 上海: 同济大学, 2003.
[17] Ip K H, Stuart B H, Thomas P S, et al. Thermal characterization of the clay binder of heritagesydney sandstones[J]. Journal of Thermal Analysis and Calorimetry, 2008, 92(1): 97-100.
[18] 陈洁渝, 严春杰, 涂晶. 苏州高岭土在不同温度下的结构和性能[J]. 非金属矿, 2009, 32(2): 21-24.
[19] 李艳, 郁青春, 杨斌, 等. 高岭土在真空下的热分解行为[J]. 真空科学与技术学报, 2012, 32(7): 599-604.
[20] 翟传鑫, 李炎, 马向东, 等. 蒙脱土的高温相变及微观结构表征[J]. 河南科技大学学报:自然科学版, 2012, 33(1): 1-4.
[21] Zuzana O, Annamária M, Silvia D, et al. Effect of thermal treatment on the bentonite properties[J].Arhiv Za Tehničke Nauke, 2012, 7(1): 49-56.
[22] Aza A D, Turrillas X, Rodriguez M A, et al. Time-resolved powder neutron diffraction study of the phase transformation sequence of kaolinite to mullite[J]. Journal of the European Ceramic Society, 2014, 34(5): 1409-1421.
[23] Živica V, Palou M. Influence of heat treatment on the pore structure of some clays-precursors for geopolymer synthesis[J]. Procedia Engineering, 2016, 15(1): 141-148.
[24] Horpibulsuk S, Rachan R, Raksachon Y. Role of fly ash on strength and microstructure development in blended cement stabilized silty clay[J]. Soils and Foundations, 2009, 49(1): 85-98.
[25] 邓玉珍, 刘慧卿, 张红玲, 等. 基于孔隙分维数的岩石分类方法[J]. 油气地质与采收率, 2007, 14(5): 23-25.
[26] 陈正发, 朱合华, 闫治国. 高温后上海软黏土的土-水特性及微观机理试验研究[J]. 岩土工程学报, 2019, 41(10): 1914-1920.
[27] 王宜庆, 易南概, 崔春义, 等. 经高温烧结处理的淤泥质土的微观结构[J]. 大连海事大学学报, 2019, 45(2): 101-107.
