-
摘要: 通过三轴剪切试验, 对比在不同加筋率和围压下, 聚丙烯纤维加筋泡沫轻质土的剪切力学特性; 研究了泡沫轻质土各强度参数与加筋率、围压之间的关系, 获取了加筋泡沫轻质土裂纹扩展规律, 建立了应力-应变全曲线方程, 提出了加筋泡沫轻质土各强度参数关于加筋率和围压的本构方程; 将不同加筋率的试验数据归一化处理后进行分析, 得到了加筋泡沫轻质土的应力-应变全曲线方程, 获取了曲线方程中各参数关于加筋率、围压2个变量之间的函数关系。分析结果表明: 加筋泡沫轻质土三轴剪切强度和黏聚力均随加筋率增加呈现先增加后减小的趋势, 在加筋率达到0.75%时达到峰值; 加筋泡沫轻质土的内摩擦角受加筋率影响较小, 说明纤维作用主要是通过改变材料黏聚力来影响加筋泡沫轻质土的强度; 而强度降低率随着加筋率增加呈现明显的下降趋势, 最大从40%左右降低至10%左右时达到稳定; 加筋率一定时, 加筋泡沫轻质土的极限强度和残余强度均随着围压的升高呈增加趋势; 经过分析体积裂纹曲线发现加筋泡沫轻质土破坏时主要经历受压、产生裂缝、纤维承受拉力限制裂缝、裂缝扩展张力过大纤维拔出4个阶段, 而加筋泡沫轻质土达到屈服阶段时往往包括裂纹的稳定扩展阶段和裂纹的不稳定扩展阶段2个裂纹发育过程, 由于缺乏筋材, 泡沫轻质土属于脆性破坏, 因此, 没有裂纹不稳定增长阶段。Abstract: Through the triaxial shear test, the shear mechanical properties of polypropylene fiber reinforced foam lightweight soil under different reinforcement ratios and confining pressures were compared. The relationships between the strength parameters of the reinforced lightweight foamed soil and the reinforcement rate and confining pressure were investigated. The crack propagation law of reinforced lightweight foamed soil was obtained, and the stress-strain full curve equation was established. The constitutive equations for the strength parameters of foam lightweight soil in terms of reinforcement ratio and confining pressure were proposed. The experimental results with different reinforcement ratios were analyzed through the data normalization. The stress-strain full curve equation of reinforced foam lightweight soil was obtained. The functional relationships between the parameters of the curve equation and the two variables(reinforcement rate and confining pressure) were obtained. Analysis result shows that the triaxial shear strength and cohesion of reinforced foamed lightweight soil emerge a trend that increases first and then decreases with the increase of the reinforcement rate, and reach the peak values when the reinforcement rate reaches 0.75%. While the reinforcement ratio has limited influence on the internal friction angle of reinforced foam lightweight soil, which indicates that the function of fiber affects the strength of reinforced foam lightweight soil by changing the cohesive force of the material. The strength reduction rate presents an obvious descend trend with the increase of the reinforcement rate, at most, it decreases from about 40% to about 10%, and then keeps stable. When the reinforcement rate is kept constant, the ultimate strength and residual strength of reinforced foamed lightweight soil present an increase trend with the confining pressure. Through analyzing the volume crack curve, it is found that the reinforced lightweight foamed soil is mainly subjected to four stages when it is damaged: compression, cracking, crack restriction because of the fiber tension, and pulling out of fiber due to the large crack extension. When the reinforced foam lightweight soil reaches the yield stage by two crack development processes: the stable and unstable growth of crack. Due to the lack of reinforcement, the failure type of foam lightweight soil belongs to brittle failure, hence, there is no instability growth stage of crack.
-
图 5 不同围压下强度降低率随加筋率曲线
Figure 5. Curves of strength reduction rate with reinforcement ratio under different confining pressures
图 6 抗剪强度指标随加筋率变化曲线
Figure 6. Changing curves of shear strength indicators with reinforcement ratio
图 11 参数i关于Rf和σ3二元函数
Figure 11. Bivariate functions of parameter i with respect to Rf and σ3
图 12 参数k关于Rf和σ3二元函数
Figure 12. Bivariate functions of parameter k with respect to Rf and σ3
图 13 参数A关于Rf和σ3二元函数
Figure 13. Bivariate functions of parameter A with respect to Rf and σ3
图 14 参数B关于Rf和σ3二元函数
Figure 14. Bivariate functions of parameter B with respect to Rf and σ3
表 1 聚丙烯纤维物理参数
Table 1. Physical parameters of polypropylene fiber
纤维名称 聚丙烯纤维 长度/mm 12 抗酸碱性能 极高 分散性 极好 燃点/℃ 580 熔点/℃ 160~180 纤维类型 束状单丝 直径/μm 31 断裂伸长率/% 10~28 弹性模量/MPa ≥3 850 密度/(g·cm-3) 0.91 抗拉强度/MPa ≥500 
下载: 导出CSV
表 2 加筋泡沫轻质土强度降低率
Table 2. Strength reduction rates of reinforced foam light soils
围压/kPa 不同加筋率(%)加筋泡沫轻质土强度降低率/% 0 0.25 0.50 0.75 1.00 1.25 1.50 50 40.16 14.58 12.24 11.14 8.20 9.44 12.66 70 34.65 16.78 11.91 8.35 7.35 10.03 11.40 100 39.48 20.15 15.87 9.85 9.83 10.60 11.21
下载: 导出CSV
表 3 抗剪强度指标汇总
Table 3. Summary of shear strength indicators
加筋率/% 0 0.25 0.50 0.75 1.00 1.25 1.50 内摩擦角/(°) 40.757 42.765 43.127 44.308 40.786 43.573 42.315 黏聚力/kPa 199.032 208.614 251.570 388.687 378.863 269.727 158.338
下载: 导出CSV
表 4 Gompertz函数拟合结果
Table 4. Fitting result of Gompertz function
加筋率/% 围压/kPa k i R2 0.00 50 3.780 0.516 0.945 0.25 50 4.471 0.179 0.942 0.50 50 5.271 0.343 0.957 0.75 50 8.500 0.294 0.964 1.00 50 11.870 0.228 0.954 1.25 50 10.420 0.229 0.947 1.50 50 7.138 0.205 0.947 0.00 70 3.665 0.531 0.947 0.25 70 4.301 0.367 0.923 0.50 70 2.302 0.533 0.945 0.75 70 6.114 0.248 0.968 1.00 70 7.202 0.398 0.946 1.25 70 5.188 0.205 0.925 1.50 70 4.937 0.313 0.969 0.00 100 3.288 0.523 0.941 0.25 100 4.131 0.456 0.947 0.50 100 3.798 0.313 0.915 0.75 100 6.237 0.372 0.923 1.00 100 4.838 0.365 0.938 1.25 100 3.798 0.313 0.937 1.50 100 5.185 0.385 0.957
下载: 导出CSV
表 5 Exponential函数拟合结果
Table 5. Fitting result of exponential function
加筋率/% 围压/kPa A B R2 0.00 50 4.185 -18.46 0.943 6 0.25 50 3.650 -28.60 0.972 4 0.50 50 4.899 -33.74 0.976 6 0.75 50 7.858 -18.09 0.948 7 1.00 50 14.787 -14.46 0.972 3 1.25 50 22.212 -7.62 0.987 7 1.50 50 2.103 -30.47 0.946 1 0.00 70 1.959 -15.62 0.960 0 0.25 70 9.870 -17.70 0.966 7 0.50 70 7.864 -20.04 0.966 3 0.75 70 1.187 -20.96 0.946 5 1.00 70 4.513 -19.91 0.945 4 1.25 70 4.385 -10.58 0.911 4 1.50 70 15.180 -11.74 0.950 3 0.00 100 1.015 -14.60 0.935 5 0.25 100 4.185 -18.46 0.933 2 0.50 100 6.603 -35.89 0.910 4 0.75 100 15.130 -5.11 0.956 4 1.00 100 2.959 -3.33 0.873 2 1.25 100 10.850 -4.44 0.966 5 1.50 100 44.900 -5.87 0.939 7
下载: 导出CSV
表 6 形状参数i统计结果
Table 6. Statistical result of shape parameter i
围压/kPa 不同加筋率(%)Gompertz形状参数i 0.00 0.25 0.50 0.75 1.00 1.25 1.50 50 0.516 0.179 0.343 0.294 0.228 0.229 0.205 70 0.531 0.367 0.533 0.248 0.398 0.205 0.313 100 0.523 0.456 0.313 0.372 0.365 0.313 0.385
下载: 导出CSV
表 7 形状参数k统计结果
Table 7. Statistical result of shape parameter k
围压/kPa 不同加筋率(%)Gompertz形状参数k 0.00 0.25 0.50 0.75 1.00 1.25 1.50 50 3.780 4.471 5.271 8.500 11.870 10.420 7.138 70 3.665 4.301 2.302 6.114 7.202 5.188 4.937 100 3.288 4.131 3.798 6.237 4.838 3.798 5.185
下载: 导出CSV
表 8 形状参数A统计结果
Table 8. Statistical result of shape parameter A
围压/kPa 不同加筋率(%)Gompertz形状参数A 0.00 0.25 0.50 0.75 1.00 1.25 1.50 50 4.185 3.650 4.899 7.858 14.787 22.212 2.103 70 1.959 9.870 7.864 1.187 4.513 4.385 15.180 100 1.015 4.185 6.603 15.130 2.959 10.850 44.900
下载: 导出CSV
表 9 形状参数B统计结果
Table 9. Statistical result of shape parameter B
围压/kPa 不同加筋率(%)Gompertz形状参数B 0.00 0.25 0.50 0.75 1.00 1.25 1.50 50 -18.46 -28.60 -33.74 -18.09 -14.46 -7.62 -30.47 70 -15.62 -17.70 -20.04 -20.96 -19.91 -10.58 -11.74 100 -14.60 -18.46 -35.89 -5.11 -3.33 -4.44 -5.87
下载: 导出CSV
-
[1] 张莎莎, 谢山杰, 杨晓华, 等. 火山灰改良粗粒硫酸盐渍土路基填料及其作用机理研究[J]. 岩土工程学报, 2019, 41(3): 588-594. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201903027.htmZHANG Sha-sha, XIE Shan-jie, YANG Xiao-hua. et al. Action mechanism of coarse particle sulfate soil subgrade modified by volcanic ash[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(3): 588-594. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201903027.htm [2] 杨晓华, 张莎莎, 郭永建. 盐渍化软弱土地基处治措施对比分析[J]. 郑州大学学报(工学版), 2010, 31(2): 22-26. https://www.cnki.com.cn/Article/CJFDTOTAL-ZZGY201002007.htmYANG Xiao-hua, ZHANG Sha-sha, GUO Yong-jian. Comparative analysis of treatment measures of saline soft soil foundation[J]. Journal of Zhengzhou University (Engineering Science), 2010, 31(2): 22-26. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-ZZGY201002007.htm [3] 晏长根, 邹群, 许昱, 等. 砂夹层黄土路基水分迁移规律[J]. 交通运输工程学报, 2016, 16(6): 21-29. http://transport.chd.edu.cn/article/id/201606003YAN Chang-gen, ZOU Qun, XU Yu, et al. Water migration rule of loess subgrade with sand interlayers[J]. Journal of Traffic and Transportation Engineering, 2016, 16(6): 21-29. (in Chinese). http://transport.chd.edu.cn/article/id/201606003 [4] JONES M R, MCCARTHY A. Utilizing unprocessed low-lime coal fly ash in foamed concrete[J]. Fuel, 2005, 84(11): 1398-1409. doi: 10.1016/j.fuel.2004.09.030 [5] KEARSLEY E P, WAINWRIGHTP J. The effect of high fly ash content on the compressive strength of foamed concrete[J]. Cement and Concrete Research, 2001, 31(1): 105-112. doi: 10.1016/S0008-8846(00)00430-0 [6] NAMBIAR E K K, RAMAMURTHY K. Influence of filler type on the properties of foam concrete[J]. Cement and Concrete Composites, 2006, 28(5): 475-480. doi: 10.1016/j.cemconcomp.2005.12.001 [7] HILAL A A, THOM N H, DAWSON A R. The use of additives to enhance properties of pre-formed foamed concrete[J]. IACSIT International Journal of Engineering and Technology, 2015, 7(4): 286-293. doi: 10.7763/IJET.2015.V7.806 [8] DAWOOD E T, HAMAD A J. Toughness behaviour of high-performance lightweight foamed concrete reinforced with hybrid fibres[J]. Structural Concrete, 2016, 16(4): 496-507. [9] YAKOVLEV G, KERIENĖ, et al. Cement based foam concrete reinforced by carbon nanotubes[J]. Materials Science, 2006, 12(2): 147-151. [10] SAGAR B S V, VARUN C S, DIVYAPRABANDHA K, et al. Fabrication and characterization of foam coir concrete[C]//American Institute of Physics. International Conference on Renewable Energy Research and Education. Melville: AIP Publishing, 2018: 040010-1-6. [11] MYDIN M A O, SAHIDUN N S, YUSOF M Y M, et al. Compressive, flexural and splitting tensile strengths of lightweight foamed concrete with inclusion of steel fibre[J]. Jurnal Teknologi, 2015, 75(5): 45-50. [12] MEYER D, VAN MIER J G M. Influence of different PVA fibres on the crack behaviour of foamed cement paste[C]//CARPINTERI A, GAMBAROVA P G, FERRO G, et al. Proceedings of Sixth International Conference on Fracture Mechanics of Concrete and Concrete Structures. London: Taylor & amp; amp; Francis Group, 2007: 1359-1365. [13] YAP S P, ALENGARAM U J, JUMAATM Z. Enhancement of mechanical properties in polypropylene and nylon-fibre reinforced oil palm shell concrete[J]. Materials and Design, 2013, 49: 1034-1041. doi: 10.1016/j.matdes.2013.02.070 [14] AWANG H, MYDIN M A O, ROSLAN A F. Effects of fibre on drying shrinkage, compressive and flexural strength of lightweight foamed concrete[J]. Advanced Materials Research, 2012, 587: 144-149. doi: 10.4028/www.scientific.net/AMR.587.144 [15] 赵文辉, 苏谦, 李婷, 等. 高速铁路基床底层泡沫轻质土填料试验研究[J]. 振动与冲击, 2019, 38(6): 179-186. https://www.cnki.com.cn/Article/CJFDTOTAL-ZDCJ201906027.htmZHAO Wen-hui, SU Qian, LI Ting, et al. Experimental study on foamed concrete as a filler of the bottom layer of high speed railway subgrade[J]. Journal of Vibration and Shock, 2019, 38(6): 179-186. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-ZDCJ201906027.htm [16] 朱红英. 泡沫混凝土配合比设计及性能研究[D]. 杨凌: 西北农林科技大学, 2013.ZHU Hong-ying. Study on mix ratio design and performance of foamed concrete[D]. Yangling: Northwest A and F University, 2013. (in Chinese). [17] 陈婷婷. 纤维增强泡沫轻质混凝土基床表层结构的力学性能分析[D]. 成都: 西南交通大学, 2017.CHEN Ting-ting. Material properties analysis of the surface layer of subgrade filled with fiber reinforced foamed lightwight concrete[D]. Chengdu: Southwest Jiaotong University, 2017. (in Chinese). [18] 周志敏. 高强度泡沫混凝土的研究[D]. 长沙: 湖南大学, 2011.ZHOU Zhi-min. High strength foam concrete research[D]. Changsha: Hunan University, 2011. (in Chinese). [19] 王滌非. 水泥泡沫混凝土的改性研究[D]. 淮南: 安徽理工大学, 2016.WANG Di-fei. Research on the modification of foam concrete[D]. Huainan: Anhui University of Science and Technology, 2016. (in Chinese). [20] 郑念念, 何真, 孙海燕, 等. 大掺量粉煤灰泡沫混凝土的性能研究[J]. 武汉理工大学学报, 2009, 31(7): 96-99, 119. https://www.cnki.com.cn/Article/CJFDTOTAL-WHGY200907024.htmZHENG Nian-nian, HE Zhen, SUN Hai-yan, et al. Research on the foamed concrete with high volume fly ash[J]. Journal of Wuhan University of Technology, 2009, 31(7): 96-99, 119. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-WHGY200907024.htm [21] 周平, 王志杰, 张家瑞, 等. 高速铁路新型路基材料的动响应减振研究[J]. 振动与冲击, 2017, 36(13): 230-237. https://www.cnki.com.cn/Article/CJFDTOTAL-ZDCJ201713038.htmZHOU Ping, WANG Zhi-jie, ZHANG Jia-rui, et al. Vibration reduction effects of new-type roadbed material of high-speed railway[J]. Journal of Vibration and Shock, 2017, 36(13): 230-237. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-ZDCJ201713038.htm [22] 陈金威, 刘勇, 石苏意, 等. 不同掺料泡沫轻质土的强度特性[J]. 长沙理工大学学报(自然科学版), 2016, 13(4): 15-22. https://www.cnki.com.cn/Article/CJFDTOTAL-HNQG201604003.htmCHEN Jin-wei, LIU Yong, SHI Su-yi, et al. Strength characteristics of foam lightweight soil with different admixture[J]. Journal of Changsha University of Science and Technology (Natural Science), 2016, 13(4): 15-22. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-HNQG201604003.htm [23] 吕锡岭. 泡沫混凝土拓宽路基的差异沉降研究[J]. 水文地质工程地质, 2012, 39(3): 75-80. https://www.cnki.com.cn/Article/CJFDTOTAL-SWDG201203017.htmLYU Xi-ling. A study of the differential settlement of subgrade widen with foam concrete[J]. Hydrogeology and Engineering Geology, 2012, 39(3): 75-80. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-SWDG201203017.htm [24] 张强, 王鑫. 泡沫轻质土处治路基耐久性能研究[J]. 城市道桥与防洪, 2017(9): 200-203, 222. https://www.cnki.com.cn/Article/CJFDTOTAL-CSDQ201709074.htmZHANG Qiang, WANG Xin. Study on endurance quality of foam light soil to treat roadbed[J]. Urban Roads Bridges and Flood Control, 2017(9): 200-203, 222. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-CSDQ201709074.htm [25] LIU Hui-hai, RUTQVIST J, BERRYMAN J G. On the relationship between stress and elastic strain for porous and fractured rock[J]. International Journal of Rock Mechanics and Mining Sciences, 2009, 46(2): 289-296. doi: 10.1016/j.ijrmms.2008.04.005 [26] 左建平, 谢和平, 孟冰冰, 等. 煤岩组合体分级加卸载特性的试验研究[J]. 岩土力学, 2011, 32(5): 1287-1296. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201105002.htmZUO Jian-ping, XIE He-ping, MENG Bing-bing, et al. Experimental research on loading-unloading behavior of coal-rock combination bodies at different stress levels[J]. Rock and Soil Mechanics, 2011, 32(5): 1287-1296. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201105002.htm [27] 左建平, 裴建良, 刘建锋, 等. 煤岩体破裂过程中声发射行为及时空演化机制[J]. 岩石力学与工程学报, 2011, 30(8): 1564-1570. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201108008.htmZUO Jian-ping, PEI Jian-liang, LIU Jian-feng, et al. Investigation on acoustic emission behavior and its time-space evolution mechanism in failure process of coal-rock combined body[J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(8): 1564-1570. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201108008.htm [28] 陈岩, 左建平, 宋洪强, 等. 煤岩组合体循环加卸载变形及裂纹演化规律研究[J]. 采矿与安全工程学报, 2018, 35(4): 826-833. https://www.cnki.com.cn/Article/CJFDTOTAL-KSYL201804022.htmCHEN Yan, ZUO Jian-ping, SONG Hong-qiang, et al. Deformation and crack evolution of coal-rock combined body under cyclic loading-unloading effects[J]. Journal of Mining and Safety Engineering, 2018, 35(4): 826-833. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-KSYL201804022.htm [29] 过镇海, 张秀琴, 张达成, 等. 混凝土应力-应变全曲线的试验研究[J]. 建筑结构学报, 1982(1): 1-12. https://www.cnki.com.cn/Article/CJFDTOTAL-JZJB201908018.htmGUO Zhen-hai, ZHANG Xiu-qin, ZHANG Da-cheng, et al. Experimental investigation of the complete stress-strain curve of concrete[J]. Journal of Building Structures, 1982(1): 1-12. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-JZJB201908018.htm [30] 余其俊, 林秋旺, 李方贤, 等. 硅酸钙板-纤维增强泡沫混凝土复合墙板的受压性能[J]. 华南理工大学学报(自然科学版), 2017, 45(9): 88-95. https://www.cnki.com.cn/Article/CJFDTOTAL-HNLG201709014.htmYU Qi-jun, LIN Qiu-wang, LI Fang-xian, et al. Structure performance of calcium silicate board/fiber-reinforced foamed concrete sandwich panel under compression[J]. Journal of South China University of Technology (Natural Science Edition), 2017, 45(9): 88-95. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-HNLG201709014.htm -
点击查看大图
图(14) / 表(9)
计量
- 文章访问数: 696
- HTML全文浏览量: 129
- PDF下载量: 3098
- 被引次数: 0
