干燥环境下膨润土-纤维改良固化土的裂隙发育特征和强度劣化机理研究

摘要/Abstract

摘要： 为研究固化土在干燥环境下的耐久性,本文利用膨润土和玻璃纤维对水泥固化土进行改良,并研究固化土在干燥环境下的裂隙发育特征和强度劣化情况,分析膨润土掺量和纤维掺量对固化土裂隙指标和无侧限抗压强度的影响规律,并借助扫描电子显微镜研究固化土的微观结构劣化机理。结果表明,在固化土中加入膨润土和纤维可明显改善固化土在干燥环境下的耐久性。当膨润土含量为6%(质量分数)、纤维含量为0.3%(质量分数)时,对固化土改良效果最佳。养护龄期为28 d的试件在干燥试验后的无侧限抗压强度折损率仅为3.6%,应力峰值后仍有较高的残余强度,且试件表面没有出现明显裂隙。干燥环境水分蒸发导致试件孔隙率和孔隙体积增大,水化产物分解,从而造成试件开裂,强度劣化。

关键词: 固化土, 膨润土, 玻璃纤维, 干燥环境, 裂隙演化, 强度劣化

Abstract: In order to study the durability of solidified soil in dry environment, bentonite and glass fiber were used to improve the cement solidified soil, and the crack evolution characteristics and strength deterioration of solidified soil in dry environment were studied. The influences of bentonite content and fiber content on crack index and unconfined compressive strength of solidified soil were analyzed, and the microstructure degradation mechanism of solidified soil was studied by scanning electron microscope. The results show that the addition of bentonite and fiber to solidified soil can significantly improve the durability of solidified soil in dry environment. When the bentonite content is 6% (mass fraction) and the fiber content is 0.3% (mass fraction), the improvement effect of solidified soil is the best. The unconfined compressive strength loss rate of specimen with curing age of 28 d after drying test is only 3.6%, and there is still a high residual strength after the peak stress, and there is no obvious crack on the surface of specimen. The evaporation of water in dry environment leads to the increase of porosity and pore volume of specimen, and the decomposition of hydration products, resulting in cracking and strength deterioration of specimen.

Key words: solidified soil, bentonite, glass fiber, dry environment, crack evolution, strength deterioration

中图分类号:

TU447

陈建华, 戴自立. 干燥环境下膨润土-纤维改良固化土的裂隙发育特征和强度劣化机理研究[J]. 硅酸盐通报, 2025, 44(3): 1170-1181.

CHEN Jianhua, DAI Zili. Crack Evolution Characteristic and Strength Deterioration Mechanism of Bentonite-Fiber Improved Solidified Soil in Dry Environments[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(3): 1170-1181.

参考文献

[1] 周永祥, 王继忠. 预拌固化土的原理及工程应用前景[J].新型建筑材料, 2019, 46(10): 117-120.
ZHOU Y X, WANG J Z. Principle of ready-mixed solidified soil and its prospects for engineering application[J].New Building Materials, 2019, 46(10): 117-120 (in Chinese).
[2] 程佳明, 王银梅, 苗世超, 等. 固化黄土的干湿循环特性研究[J].工程地质学报, 2014, 22(2): 226-232.
CHENG J M, WANG Y M, MIAO S C, et al. Property study of solidified loess under wet-dry cycles[J].Journal of Engineering Geology, 2014, 22(2): 226-232 (in Chinese).
[3] ZHU Y P, LIU D R, FANG G W, et al. Utilization of excavated loess and gravel soil in controlled low strength material: laboratory and field tests[J].Construction and Building Materials, 2022, 360: 129604.
[4] QIAN J S, HU Y Y, ZHANG J K, et al. Evaluation the performance of controlled low strength material made of excess excavated soil[J].Journal of Cleaner Production, 2019, 214: 79-88.
[5] 魏丽, 杨光, 尚军, 等. 冻融损伤过程中纤维加筋土的抗压性能与裂隙演化[J].土木工程学报, 2024, 57(4): 81-91.
WEI L, YANG G, SHANG J, et al. Compressive properties and crack evolution characteristics of fiber reinforced soil under freeze-thaw cycling[J].China Civil Engineering Journal, 2024, 57(4): 81-91 (in Chinese).
[6] 董猛荣, 杨俊杰, 王曼, 等. 海相软土场地水泥土劣化机理室内试验研究[J].中国海洋大学学报(自然科学版), 2020, 50(1): 93-103.
DONG M R, YANG J J, WANG M, et al. Laboratory study on deterioration mechanism of cement soil in marine clay sites[J].Periodical of Ocean University of China, 2020, 50(1): 93-103 (in Chinese).
[7] KANIRAJ S R, HAVANAGI V G. Behavior of cement-stabilized fiber-reinforced fly ash-soil mixtures[J].Journal of Geotechnical and Geoenvironmental Engineering, 2001, 127(7): 574-584.
[8] ANAGNOSTOPOULOS C A, PAPALIANGAS T T. Experimental investigation of epoxy resin and sand mixes[J].Journal of Geotechnical and Geoenvironmental Engineering, 2012, 138(7): 841-849.
[9] KHATTAK M J, ALRASHIDI M. Durability and mechanistic characteristics of fiber reinforced soil-cement mixtures[J].International Journal of Pavement Engineering, 2006, 7(1): 53-62.
[10] DHAKAL S, KOLAY P, PURI V. Durability of clayey soil stabilized with calcium sulfoaluminate cement and polypropylene fiber under extreme environment[J].Transportation Geotechnics, 2024, 44: 101164.
[11] 王天, 翁兴中, 张俊, 等. 干湿循环条件下复合固化砂土抗压强度试验研究[J].铁道科学与工程学报, 2017, 14(4): 721-729.
WANG T, WENG X Z, ZHANG J, et al. Strength characteristics of fiber-reinforced solidified sand under dry-wet cycles[J].Journal of Railway Science and Engineering, 2017, 14(4): 721-729 (in Chinese).
[12] 李文涛, 陈凤, 肖衡林, 等. 干湿、冻融循环作用下石灰-赤泥固化土的物理、力学和微观特性研究(英文)[J].水利水电技术, 2023, 54(6): 189-201.
LI W T, CHEN F, XIAO H L, et al. Physical, mechanical and microscopic properties of lime-red mud solidified soil under dry-wet and freeze-thaw cycles[J].Water conservancy and hydropower technology, 2023, 54(6): 189-201 (in Chinese).
[13] SHU H, YU Q B, NIU C C, et al. The coupling effects of wet-dry and freeze-thaw cycles on the mechanical properties of saline soil synergistically solidified with sulfur-free lignin, basalt fiber and hydrophobic polymer[J].Catena, 2024, 238: 107832.
[14] WU Z P, XU J, FAN H H, et al. Experimental study on dry-wet durability and water stability properties of fiber-reinforced and geopolymer-stabilized loess[J].Construction and Building Materials, 2024, 418: 135379.
[15] 刘瑾, 车文越, 郝社锋, 等. 基于CT技术的黄原胶加固土干湿循环条件下力学性能和微观结构劣化机制研究[J].岩土工程学报, 2024, 46(5): 1119-1126.
LIU J, CHE W Y, HAO S F, et al. Deterioration mechanism of mechanical properties and microstructure in xanthan gum-reinforced soil under wetting-drying cycles based on CT scanning technology[J].Chinese Journal of Geotechnical Engineering, 2024, 46(5): 1119-1126 (in Chinese).
[16] 高梦娜, 王旭, 李建东, 等. 膨润土石灰改良黄土强度及微观结构试验研究[J].水利水运工程学报, 2022, 5: 86-93.
GAO M N, WANG X, LI J D, et al. Experiment study on the strength and microstructure of bentonite-lime improved loess[J].Hydro-Science and Engineering, 2022, 5: 86-93 (in Chinese).
[17] 王聪聪, 刘茂青, 宋红旗, 等. 赤泥-钢渣粉-水泥固化流态土性能试验研究[J].硅酸盐通报, 2023, 42(7): 2488-2496.
WANG C C, LIU M Q, SONG H Q, et al. Experimental study on properties of red mud, steel slag powder and cement solidified fluidized soil[J].Bulletin of the Chinese Ceramic Society, 2023, 42(7): 2488-2496 (in Chinese).
[18] 王秋生, 修一兵, 齐云鹏, 等. 水泥固化土固化机理及抗冲刷特性[J].长江科学院院报, 2024, 41(8): 142-149.
WANG Q S, XIU Y B, QI Y P, et al. Curing mechanism and erosion resistance of cement-solidified soil[J].Journal of Changjiang River Scientific Research Institute, 2024, 41(8): 142-149 (in Chinese).
[19] XIAO Y, TONG L Y, CHE H B, et al. Experimental studies on compressive and tensile strength of cement-stabilized soil reinforced with rice husks and polypropylene fibers[J].Construction and Building Materials, 2022, 344: 128242.
[20] ZHANG X D, PANG S, GENG J, et al. Study on shear resistance and crack resistance and toughening mechanism of fiber reinforced cement stabilized aeolian sand[J].Theoretical and Applied Fracture Mechanics, 2023, 123: 103700.
[21] NAHLAWI H, KODIKARA J K. Laboratory experiments on desiccation cracking of thin soil layers[J].Geotechnical and Geological Engineering, 2006, 24 (6): 1641-1664.
[22] CONSOLI N C, CRUZ R C, FLOSS M F, et al. Parameters controlling tensile and compressive strength of artificially cemented sand[J].Journal of Geotechnical and Geoenvironmental Engineering, 2010, 136(5): 759-763.
[23] 宁建国, 黄新, 许晟. 土样pH值对固化土抗压强度增长的影响研究[J].岩土工程学报, 2007, 29(1): 98-102.
NING J G, HUANG X, XU S. Effect of pH value of soil on strength increasing of the stabilized soil[J].Chinese Journal of Geotechnical Engineering, 2007, 29(1): 98-102 (in Chinese).
[24] 黄新, 宁建国, 许晟, 等. 固化土孔隙液Ca(OH)₂饱和度对强度的影响[J].工业建筑, 2006, 36(7): 19-24.
HUANG X, NING J G, XU S, et al. Influence of Ca(OH)₂ concentration in the pore solution on strength increasing of the stabilized soil[J].Industrial Construction, 2006, 36(7): 19-24 (in Chinese).
[25] 钱觉时, 余金城, 孙化强, 等. 钙矾石的形成与作用[J].硅酸盐学报, 2017, 45(11): 1569-1581.
QIAN J S, YU J C, SUN H Q, et al. Formation and function of ettringite in cement hydrates[J].Journal of the Chinese Ceramic Society, 2017, 45(11): 1569-1581 (in Chinese).
[26] TAYLOR H F W. Cement chemistry[M].2nd ed. London: Thomas Telford, 1997.
[27] 陈宇航, 唐昊陵, 章定文. 膨润土对双轮铣水泥土搅拌墙体强度和渗透特性的影响[J].土木与环境工程学报, 2020, 42(6): 31-37.
CHEN Y H, TANG H L, ZHANG D W. Influence of bentonite on the unconfined compressive strength and hydraulic characteristics of cutter soil mixing wall[J].Journal of Civil and Environmental Engineering, 2020, 42(6): 31-37 (in Chinese).
[28] 刘振亚, 刘建坤, 李旭, 等. 非饱和膨润土失水收缩与冻结体变关系研究[J].岩土工程学报, 2018, 40(增刊1): 229-234.
LIU Z Y, LIU J K, LI X, et al. Experimental study on air-dried shrinkage and frozen deformation characteristics of unsaturated bentonite[J].Chinese Journal of Geotechnical Engineering, 2018, 40(supplement 1): 229-234 (in Chinese).
[29] 姜恒超, 李青林, 杨志勇, 等. 玻璃纤维水泥改良土劈裂抗拉强度试验研究[J].铁道科学与工程学报, 2019, 16(11): 2742-2747.
JIANG H C, LI Q L, YANG Z Y, et al. Experimental study on split tensile strength of glass fiber cement improved soil[J].Journal of Railway Science and Engineering, 2019, 16(11): 2742-2747 (in Chinese).
[30] TANG C S, SHI B, GAO W, et al. Strength and mechanical behavior of short polypropylene fiber reinforced and cement stabilized clayey soil[J].Geotextiles and Geomembranes, 2007, 25(3): 194-202.
[31] TRAN K Q, SATOMI T, TAKAHASHI H. Effect of waste cornsilk fiber reinforcement on mechanical properties of soft soils[J].Transportation Geotechnics, 2018, 16: 76-84.
[32] WANG S N, CHEN F Y, XUE Q P, et al. Splitting tensile strength of cement soil reinforced with basalt fibers[J].Materials, 2020, 13(14): 3110.