-
摘要: 为了充分利用全风化千枚岩作为路基填料，设计了红黏土掺和比分别为0、20%、40%、60%和100%，水泥掺量分别为0、3%和5%的组合改良方案，开展了改良土的界限含水率、抗剪强度和无侧限抗压强度试验，分析了改良土的路用性能。试验结果表明：当水泥掺量分别为3%与5%时，复合改良土的液限均低于40%，符合路基设计中液限低于40%的控制要求；改良土的黏聚力随红黏土掺和比与水泥掺量的增大而增大，内摩擦角随红黏土掺和比的增长先增大后减小，随水泥掺量的增大而增大，但两指标在水泥掺量大于3%时增长幅度较小。改良土路基极限承载力计算结果表明：5%水泥改良全风化千枚岩路基极限承载力仅为725.3 kPa，红黏土掺和比为40%改良全风化千枚岩路基极限承载力达到2 198.3 kPa，分别是全风化千枚岩路基承载力的2.34和7.10倍，因此，红黏土改良效果优于水泥；经过比较可得红黏土掺和比为40%，水泥掺量为3%是合理掺和方案，在28 d养护后，路基极限承载力计算值为4 247.7 kPa，液限为32.7%。微观机理分析结果表明：红黏土颗粒小于全风化千枚岩颗粒，当红黏土掺和比大于40%时可以包围千枚岩颗粒的点-点接触，增加了接触点数与接触面积，从而大大提高了改良土路基的极限承载力。无侧限抗压强度试验结果表明：优化方案改良土7 d无侧限抗压强度为487.25 kPa，满足铁路路基设计要求。Abstract: In order to make full use of completely weathered phyllite as subgrade filler, the combined improvement schemes were designed, in which red clay blending ratio was 0, 20%, 40%, 60%, and 100%, respectively, and cement content is 0, 3%, and 5%, respectively. The tests of boundary moisture content, shear strength and unconfined compression of the improved soil were carried out, and the road performances of the improved soil were analyzed. The test results of the improved soil show that the liquid limit of the improved soil is lower than 40% when cement content is 3% or 5%, and all improved soils comply with the liquid limit control requirement of the design of railway earth structure (less than 40%). The cohesion of the improved soil increases with the increase of red clay blending ratio and cement content. The internal friction angle of the improved soil increases first and then decreases with the increase of red clay blending ratio, and increases with the increase of cement content. But both shear indexes increase slightly when cement content is more than 3%. The calculation results of ultimate bearing capacity of the improved completely weathered phyllite subgrade show that the ultimate bearing capacity of the subgrade with 5% cement is only 725.3 kPa, and the value of the subgrade with 40% red clay is 2 198.3 kPa, being 2.34 and 7.10 times that of the completely weathered phyllite subgrade, respectively. Therefore, the improvement effect of red clay is better than that of cement. Analysis results show that the rational mixing scheme is that red clay blending ratio is 40% and cement content is 3%. Under the scheme, when the curing age is 28 days, the calculated value of the ultimate bearing capacity of the improved completely weathered phyllite subgrade is 4 247.7 kPa, and the liquid limit of the improved completely weathered phyllite is 32.7%. Microscopic mechanism analysis results show that red clay particles are smaller than fully weathered phyllite particles. When red clay blending ratio is greater than 40%, red clay can surround the point-to-point contact of phyllite particles, and increase the contact points and contact area, which greatly improves the ultimate bearing capacity of the improved soil subgrade. The test results of unconfined compressive strength show that the 7-day unconfined compressive strength of the improved soil in the optimized scheme is 487.25 kPa, which meets the requirement of the design of railway earth structure. 2 tabs, 17 figs, 30 refs.
-
图 10 路基极限承载力计算模型
Figure 10. Calculation models of ultimate bearing capacity of subgrade
图 11 极限承载力随红黏土掺和比的变化规律
Figure 11. Variation laws of ultimate bearing capacity with red clay blending ratio
图 12 极限承载力随水泥掺量的变化规律
Figure 12. Variation laws of ultimate bearing capacity with cement content
图 13 极限承载力随养护龄期的变化规律
Figure 13. Variation laws of ultimate bearing capacity with curing age
表 1 试验材料物理指标
Table 1. Physical indices of test materials
土的类型 液限/% 塑限/% 塑性指数 比重 最大干密度/(g·cm-3) 最优含水率/% 天然含水率/% 全风化千枚岩 43.3 28.9 14.4 2.76 1.64 19.2 8.48 红黏土 48.4 26.4 22.0 2.69 1.75 17.8 22.31 
下载: 导出CSV
表 2 根据φ确定Nγ
Table 2. Determining Nγ according to φ
φ/(°) Nγ φ/(°) Nγ 21 4.31 31 22.65 22 5.09 32 26.87 23 6.00 33 31.94 24 7.08 34 38.04 25 8.34 35 45.41 26 9.84 36 54.36 27 11.60 37 65.27 28 13.70 38 78.61 29 16.18 39 95.03 30 19.13 40 116.31
下载: 导出CSV
-
[1] SIMON N, ROSLEE R, RAFEK A G, et al. Research article rock mass assessment using geological strength index (GSI) along the Ranau-Tambunan Road, Sabah, Malaysia[J]. Research Journal of Applied Sciences, Engineering and Technology, 2016, 12(1): 108-115. doi: 10.19026/rjaset.12.2309 [2] 吴永胜, 谭忠盛, 喻渝, 等. 川西北茂县群千枚岩各向异性力学特性[J]. 岩土力学, 2018, 39(1): 207-215. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201801026.htmWU Yong-sheng, TAN Zhong-sheng, YU Yu, et al. Anisotropically mechanical characteristics of Maoxian group phyllite in northwest of Sichuan Province[J]. Rock and Soil Mechanics, 2018, 39(1): 207-215. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201801026.htm [3] LIU Fei-fei, MAO Xue-song, ZHANG Hui-jun, et al. Investigating the deformation property of weathered phyllite filling subgrade[J]. Journal of Testing and Evaluation, 2020, 48(5): 3643-3657. [4] FENG Wen-kai, HUANG Run-qiu, LI Tian-bin. Deformation analysis of a soft-hard rock contact zone surrounding a tunnel[J]. Tunnelling and Underground Space Technology, 2012, 32: 190-197. doi: 10.1016/j.tust.2012.06.011 [5] LI Xin-zhe, WANG Geng-feng, CAO Ling. Test research on influence of water and mineral composition on physical and mechanical properties of phyllite[J]. Applied Mechanics and Materials, 2014, 496-500: 2398-2401. doi: 10.4028/www.scientific.net/AMM.496-500.2398 [6] HU Kai-feng, FENG Qian, WANG Xu-tao. Experimental research on mechanical property of phyllite tunnel surrounding rock under different moisture state[J]. Geotechnical and Geological Engineering, 2017, 35(1): 303-311. doi: 10.1007/s10706-016-0107-6 [7] GARZÓN E, SÁNCHEZ-SOTO P J, ROMERO E. Physical and geotechnical properties of clay phyllites[J]. Applied Clay Science, 2010, 48(3): 307-318. doi: 10.1016/j.clay.2009.12.022 [8] GARZÓN E, CANO M, O'KELLY B C, et al. Phyllite clay-cement composites having improved engineering properties and material applications[J]. Applied Clay Science, 2015, 114(2): 229-233. [9] GARZÓN E, CANO M, OKELLY B C, et al. Effect of lime on stabilization of phyllite clays[J]. Applied Clay Science, 2016, 123(3): 329-334. [10] MORALES L, GARZÓN E, ROMERO E, et al. Microbiological induced carbonate (CaCO3) precipitation using clay phyllites to replace chemical stabilizers (cement or lime)[J]. Applied Clay Science, 2019, 174(1): 15-28. [11] YAO Kai, CHEN Qing-sheng, XIAO Hua-wen. Small-strain shear modulus of cement-treated marine clay[J]. Journal of Materials in Civil Engineering, 2020, 32(6): 04020114. doi: 10.1061/(ASCE)MT.1943-5533.0003153 [12] MOUSAVI S E. Stabilization of compacted clay with cement and/or lime containing peat ash[J]. Road Materials and Pavement Design, 2017, 18(6): 1304-1321. doi: 10.1080/14680629.2016.1212729 [13] 毛雪松, 朱凤杰, 黄喆, 等. 改良千枚岩填料的CBR值影响因素分析[J]. 重庆交通大学学报(自然科学版), 2017, 36(2): 43-48. https://www.cnki.com.cn/Article/CJFDTOTAL-CQJT201702008.htmMAO Xue-song, ZHU Feng-jie, HUANG Zhe, et al. Analysis of the influences on CBR value of improved phyllite filler as a fill[J]. Journal of Chongqing Jiaotong University (Natural Science), 2017, 36(2): 43-48. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-CQJT201702008.htm [14] 贺建清, 罗婉, 蒋鑫, 等. 非饱和高液限红粘土土-水特征试验研究[J]. 自然灾害学报, 2014, 23(6): 249-255.HE Jian-qing, LUO Wan, JIANG Xin, et al. Experimental study on soil-water characteristics of red clay with unsaturated high liquid limit[J]. Journal of natural disasters, 2014, 23(6): 249-255. (in Chinese) [15] 赵秀绍, 付智涛, 耿大新, 等. 千枚岩土掺入红黏土微观结构与压缩特性试验研究[J]. 科学技术与工程, 2020, 20(21): 8732-8738. doi: 10.3969/j.issn.1671-1815.2020.21.045ZHAO Xiu-shao, FU Zhi-tao, GENG Da-xin, et al. Experimental research on microstructures and compression characteristics of phyllite weatherized soil blended with red clay[J]. Science Technology and Engineering, 2020, 20(21): 8732-8738. (in Chinese) doi: 10.3969/j.issn.1671-1815.2020.21.045 [16] 蒋红光, 曹让, 马晓燕, 等. 考虑持水能力的黄泛区高液限黏土路用压实标准[J]. 湖南大学学报(自然科学版), 2019, 46(11): 154-163. https://www.cnki.com.cn/Article/CJFDTOTAL-HNDX201911018.htmJIANG Hong-guang, CAO Rang, MA Xiao-yan, et al. Subgrade compaction control standard of high liquid limit clay in Shandong Yellow River Flood Area considering its water retaining characteristics[J]. Journal of Hunan University(Natural Sciences), 2019, 46(11): 154-163. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HNDX201911018.htm [17] DU Bin, BAI Hai-bo, WU Guang-ming. Dynamic compression properties and deterioration of red-sandstone subject to cyclic wet-dry treatment[J]. Advances in Civil Engineering, 2019, 2019: 1-10. [18] XU You-wei, WILLIAMS D J, SERATI M. Investigation of shear strength of interface between roadbase and geosynthetics using large-scale single-stage and multi-stage direct shear test[J]. Road Materials and Pavement Design, 2020, 21(6): 1588-1611. doi: 10.1080/14680629.2018.1561378 [19] 穆坤, 孔令伟, 张先伟, 等. 红黏土工程性状的干湿循环效应试验研究[J]. 岩土力学, 2016, 37(8): 2247-2253. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201608016.htmMU Kun, KONG Ling-wei, ZHANG Xian-wei. et al. Experimental investigation on engineering behaviors of red clay under effect of wetting-drying cycles[J]. Rock and Soil Mechanics, 2016, 37(8): 2247-2253. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201608016.htm [20] ZHAO Yu-long, GAO Ying, ZHANG Yi-luo, et al. Effect of fines on the drying crack resistance of composite soil stabilizer-stabilized gravel soil[J]. Road Materials and Pavement Design, 2019, 20(6): 1255-1274. doi: 10.1080/14680629.2018.1439766 [21] SUBHRADEEP D, MONOWAR H. The strength behaviour of lime-stabilized plastic fibre-reinforced clayey soil[J]. Road Materials and Pavement Design, 2019, 20(8): 1757-1778. doi: 10.1080/14680629.2018.1468803 [22] STOLTZ G, CUISINIER O, MASROURI F. Multi-scale analysis of the swelling and shrinkage of a lime-treated expansive clayeysoil[J]. Applied Clay Science, 2012, 61(1): 44-51. [23] MANDAL T, EDIL T B, TINJUM J M. Study on flexural strength, modulus, and fatigue cracking of cementitiously stabilized materials[J]. Road Materials and Pavement Design, 2018, 19(7): 1546-1562. doi: 10.1080/14680629.2017.1325772 [24] AZZAM W R. Utilization of polymer stabilization for improvement of clay microstructures[J]. Applied Clay Science, 2014, 93-94: 94-101. doi: 10.1016/j.clay.2014.03.006 [25] 张先伟, 孔令伟. 氧化铁胶体与黏土矿物的交互作用及其对黏土土性影响[J]. 岩土工程学报, 2014, 36(1): 65-74. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201401007.htmZHANG Xin-wei, KONG Ling-wei. Interaction between iron oxide colloids and clay minerals and its effect on properties of clay[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(1): 65-74. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201401007.htm [26] 谭罗荣, 孔令伟. 某类红粘土的基本特性与微观结构模型[J]. 岩土工程学报, 2001, 23(4): 458-462. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200104017.htmTAN Luo-rong, KONG Ling-wei. Fundamental property and microstructure model of red clay[J]. Chinese Journal of Geotechnical Engineering, 2001, 23(4): 458-462. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200104017.htm [27] ZHAO Xiu-shao, FU Zhi-tao, YANG Qi-jing, et al. Subgrade fill strength and bearing characteristics of weathered phyllite blended with red clay[J]. Road Materials and Pavement Design, 2020, 21(4): 1-20. [28] ZHAO Xiu-shao, WANG Zhi-yao, CHEN Kai-sheng, et al. Measurement and calculation of fissure area and density for shrinkage soil[J]. Earth and Environmental Science, 2020, 560(1): 1-6. [29] ZHAO Xiu-shao, YANG Qi-jing, RAO Jiang-long, et al. Study of mutual improvement of completed weathered phyllite and red clay based on neutralization effects of swelling and shrinkage deformation[J]. Journal of Renewable Materials, 2021, 9(12): 203-218. [30] 孔令伟, 罗鸿禧, 袁建新. 红粘土有效胶结特征的初步研究[J]. 岩土工程学报, 1995, 17(5): 42-47. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC505.006.htmKONG Ling-wei, LUO Hong-xi, YUAN Jian-xin. Preliminary study on the effective cementation characteristics of the red clay[J]. Chinese Journal of Geotechnical Engineering, 1995, 17(5): 42-47. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC505.006.htm -
点击查看大图
图(16) / 表(2)
计量
- 文章访问数: 467
- HTML全文浏览量: 173
- PDF下载量: 67
- 被引次数: 0
