聚氨酯加固是一种新型环保快速的土质改良方法。针对南海钙质砂采用聚氨酯快速改良,并通过室内试验验证该处置方法的有效性和适用性。通过对聚氨酯固化钙质砂试样开展无侧限抗压强度试验、静力荷载和循环荷载下的三轴试验以及渗透试验,研究聚氨酯固化钙质砂的最佳凝胶时间,静、动强度特性及渗透特性。试验结果表明:固化试样的最佳凝胶时间为6.5 h;随着掺量的增加,固化钙质砂黏聚力得到显著提高,内摩擦角基本保持不变,在海水环境养护下的聚氨酯钙质砂仍然保持了较高的强度;随着掺量的增加,聚氨酯钙质砂的初始动剪切模量增加,最大阻尼比降低;钙质素砂渗透系数的数量级为10-6,掺入2%~10%聚氨酯后数量级降至10-8~10-7,聚氨酯补漏效果较好。
Abstract
Polyurethane improvement is a novel, eco-friendly, and rapid method for soil improvement. This study aims to evaluate the effectiveness and applicability of polyurethane rapid improvement for calcareous sand in the South China Sea. The optimal gelling time, static and dynamic strength, and permeability characteristics of polyurethane-cured calcareous sand were investigated through unconfined compressive strength tests, static and cyclic load triaxial tests, and permeability tests. The obtained results encompass both mechanical and permeability properties. Notable findings include: 1) the optimum gelling time for the cured samples is 6.5 hours. 2) The cohesion of the cured calcareous sand significantly improves with increasing polyurethane content, while the internal friction angle remains relatively unchanged. The polyurethane calcareous sand cured in sea water maintains a high strength. 3) Increasing the polyurethane content leads to an increased initial dynamic shear modulus of the calcareous sand, but a reduced maximum damping ratio. 4) The permeability coefficient of the calcareous sand ranges around 10-6. However, upon adding polyurethane (2%-10%), this value decreases to 10-8-10-7, demonstrating a remarkable sealing effect of polyurethane.
关键词
钙质砂 /
聚氨酯 /
凝胶时间 /
力学特性 /
渗透系数
Key words
calcareous sand /
polyurethane /
gelling time /
mechanical properties /
permeability coefficient
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 刘崇权, 杨志强, 汪 稔. 钙质土力学性质研究现状与进展[J]. 岩土力学, 1995, 16(4): 74-84. (LIU Chong-quan, YANG Zhi-qiang, WANG Ren. The Present Condition and Development in Studies of Mechanical Properties of Calcareous Soils[J]. Rock and Soil Mechanics, 1995, 16(4): 74-84.(in Chinese))
[2] 刘崇权, 汪 稔. 钙质砂物理力学性质初探[J]. 岩土力学, 1998, 19(1): 32-37. (LIU Chong-quan, WANG Ren. Preliminary Research on Physical and Mechanical Properties of Calcareous Sand[J]. Rock and Soil Mechanics, 1998, 19(1): 32-37.(in Chinese))
[3] 刘崇权, 汪 稔, 吴新生. 钙质砂物理力学性质试验中的几个问题[J]. 岩石力学与工程学报, 1999, 18(2): 209-212.(LIU Chong-quan, WANG Ren, WU Xin-sheng. Some Problems for the Tests of Physico-mechanical Properties of Calcareous Sand[J]. Chinese Journal of Rock Mechanics and Engineering, 1999, 18(2): 209-212.(in Chinese))
[4] 李 捷, 方祥位, 张 伟, 等. 珊瑚砂工程处理研究进展[J]. 水利与建筑工程学报, 2017, 15(2): 43-48. (LI Jie, FANG Xiang-wei, ZHANG Wei, et al. Research Progress in Engineering Treatments of Coral Sand[J]. Journal of Water Resources and Architectural Engineering, 2017, 15(2): 43-48.(in Chinese))
[5] 余克服, 张光学, 汪 稔. 南海珊瑚礁: 从全球变化到油气勘探: 第三届地球系统科学大会专题评述[J]. 地球科学进展, 2014, 29(11): 1287-1293. (YU Ke-fu, ZHANG Guang-xue, WANG Ren. Studies on the Coral Reefs of the South China Sea: From Global Change to Oil-gas Exploration[J]. Advances in Earth Science, 2014, 29(11): 1287-1293.(in Chinese))
[6] DEHNAVI Y,SHAHNAZARI H,SALEHZADEH H,et al.Compressibility and Undrained Behavior of Hormuz Calcareous Sand[J]. Electronic Journal of Geotechnical Engineering, 2010, 15(3):1684-1702.
[7] COOP M R. The Mechanics of Uncemented Carbonate Sands[J]. Géotechnique, 1990, 40(4):607-626.
[8] MA L J, LI Z, LIU J G, et al. Mechanical Properties of Coral Concrete Subjected to Uniaxial Dynamic Compression[J]. Construction and Building Materials, 2019, 15(3):244-255.
[9] BUZZI O, FITYUS S, SLOAN S W, et al. Use of Expanding Polyurethane Resin to Remediate Expansive Soil Foundations[J]. Canadian Geotechnical Journal, 2010,15(2):11-13.
[10] WOODWARD P K, EL KACIMI A, LAGHROUCHE O, et al. Application of Polyurethane Geocomposites to Help Maintain Track Geometry for High-speed Ballasted Railway Tracks[J]. Journal of Zhejiang University SCIENCE A, 2012, 13(11): 836-849.
[11] 刘 平, 刘汉龙, 肖 杨, 等. 高聚物胶凝堆石料静力特性试验研究[J]. 岩土力学, 2015, 36(3): 749-754. (LIU Ping, LIU Han-long, XIAO Yang, et al. Experimental Research on Mechanical Properties of PFA-reinforced Rockfill Materials[J]. Rock and Soil Mechanics, 2015, 36(3): 749-754.(in Chinese))
[12] 刘汉龙, 刘 平, 杨 贵, 等. 高聚物胶凝堆石料动残余变形特性试验研究[J]. 岩土力学, 2017, 38(7): 1863-1868, 1886. (LIU Han-long, LIU Ping, YANG Gui, et al. Experimental Investigations on Dynamic Residual Deformation Behaviors of PFA-reinforced Rockfill Materials[J]. Rock and Soil Mechanics, 2017, 38(7): 1863-1868, 1886.(in Chinese))
[13] GAO H M, LI X, WANG Z H, et al. Dynamic Shear Modulus and Damping of Expanded Polystyrene Composite Soils at Low Strains[J]. Geosynthetics International, 2019, 26(4):1-44.
[14] 刘萌成, 胡帅峰, 戴鹏飞. 南海钙质砂不排水剪切特性三轴试验[J]. 中国公路学报, 2022, 35(4): 69-76. (LIU Meng-cheng, HU Shuai-feng, DAI Peng-fei. Investigation on Shear Behavior of Calcareous Sand in South China Sea in Undrained Triaxial Tests[J]. China Journal of Highway and Transport, 2022, 35(4): 69-76.(in Chinese))
[15] 胡明鉴,崔 翔,王新志,等.细颗粒对钙质砂渗透性的影响试验研究[J].岩土力学,2019,40(8):2925-2930.(HU Ming-jian,CUI Xiang,WANG Xin-zhi,et al. Experimental Study of the Effect of Fine Particles on Permeability of the Calcareous Sand[J]. Rock and Soil Mechanics, 2019, 40(8): 2925-2930.(in Chinese))
[16] 刘 鑫, 李 飒,刘小龙,等.南海钙质砂的动剪切模量与阻尼比试验研究[J].岩土工程学报,2019,41(9):1773-1780.(LIU Xin,LI Sa,LIU Xiao-long,et al. Experimental Study on Dynamic Shear Modulus and Damping Ratio of Calcareous Sands in the South China Sea[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(9):1773-1780.(in Chinese))
[17] 廖仁国, 周先齐, 蔡燕燕, 等. 钙质砂与石英砂渗透性差异对比试验[J]. 华侨大学学报(自然科学版), 2019, 40(5):600-605.(LIAO Ren-guo, ZHOU Xian-qi, CAI Yan-yan, et al. Comparative Experiment on Permeability Difference Between Calcareous Sand and Quartz Sand[J]. Journal of Huaqiao University (Natural Science), 2019, 40(5):600-605.(in Chinese))
基金
湖南省教育厅重点和优秀青年项目(23A0141,17B260);湖湘高层次人才聚集工程——创新团队项目(2019RS1059)
PDF(5757 KB)
