Experimental study on mechanisms and applications of MgO-carbonated composite pile
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摘要: 介绍了一种基于MgO碳化固化软弱土技术的碳化复合桩（MCP），通过透气管桩向MgO搅拌桩注入CO2气体进行碳化形成新型复合桩。进行了室内模型试验，通过对碳化过程和碳化后的温度、物理、力学等特性的分析，论证了该技术在粉土和淤泥质土中的适应性，结果表明，在MgO充分水化的条件下，不同深度的碳化反应较为均匀；在透气管桩外围存在有效碳化距离和最大碳化距离，在有效碳化距离内可获取良好的碳化效果，揭示了MCP的形成机理与影响因素。在室内试验基础上开展了现场应用试验，结果表明，MCP施工工艺方便、成桩效果好且桩身强度均匀，碳化桩体标贯击数均值为39；其单桩竖向极限承载力为1920 kN，相对于PHC管桩提升37%。室内与现场试验表明，MCP复合桩兼具固碳与加固效果，对岩土工程低碳化发展具有重要意义。Abstract: A kind of MgO-carbonated composite pile (MCP) is proposed based on the MgO-carbonation solidification technology for soft soil improvement. The MCP is formed by injecting CO2 gas into the MgO-mixing column through a gas-permeable concrete pile (inner core) to achieve carbonation. The laboratory model tests are conducted to analyze and demonstrate the application effectiveness of this technology in silt and silty soils, including the temperature, physical and mechanical characteristics during and after carbonation. The model test results indicate that under the full hydration of MgO in the mixing column, the carbonation reaction is relatively uniform at different depths. There are effective and maximum carbonation distances around the gas-permeable concrete pile, and satisfactory carbonation effects can be achieved within the effective carbonation distance. Then the formation mechanisms and influencing factors of the MCP are summarized. Field trials are carried out to confirm the engineering applicability of the MCP. The results demonstrate that the MCP exhibits good pile formation performance with high pile strength, with an average N-value of 39 for standard penetration tests. The ultimate vertical bearing capacity of the MCP is 1920 kN, which is 37.1% higher than that of the PHC (prestressed high-strength concrete) piles. The laboratory model tests and field trials have demonstrated that the MCP possesses both carbon fixation and reinforcement effects, which are of great significance for the low-carbon development of geotechnical engineering.
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图 5 #1、#2模型试验不同深度碳化过程温度示意图
Figure 5. Temperature change at different depths in model tests No. 1 and No. 2
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图 6 距透气管桩不同距离处温度变化图
Figure 6. Temperature change at different distances to ventilation pipe pile
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图 7 不同深度固化粉土无侧限抗压强度图
Figure 7. Unconfined compressive strengths of stabilized silty soil at different depths
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图 8 距透气管桩不同距离固化粉土无侧限抗压强度
Figure 8. Unconfined compressive strengths of stabilized silty soil at different distances to ventilation pipe pile
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图 9 距透气管桩不同距离处动回弹模量
Figure 9. Dynamic moduli at different distances to ventilation pipe pile
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图 10 距透气管桩不同距离贯入度
Figure 10. Penetrations at different distance to ventilation pipe pile
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图 11 距透气管桩不同距离处贯入曲线
Figure 11. Penetration curves at different distances to ventilation pipe pile
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图 13 场地地层剖面及静力触探曲线
Figure 13. Stratification along depth and results of cone penetration tests
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图 14 现场试验中碳化复合桩（MCP）的示意图
Figure 14. Schematic diagram of MgO-carbonated composite piles in field trials
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图 15 MCP单桩竖向载荷试验加载模式
Figure 15. Two loading patterns used in static load tests on MCP piles
表 1 试验土样的主要理化指标
Table 1 Main physicochemical indexes of test soils
土样来源 土类 含水率/% 相对质量密度 pH 塑限wP/% 液限wL/% 宿迁 粉土 26.1 2.71 8.78 23.9 33.8 宜兴 淤泥质土 63.0 2.72 7.26 20.3 48.9 
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表 2 材料的化学成分
Table 2 Chemical compositions of materials
单位: % 成分 SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O P2O5 SO3 TiO2 MnO2 其他 粉土 71.80 10.20 3.57 6.41 1.22 0.05 3.10 0.51 0.27 — — — 淤泥质土 69.79 17.84 5.34 1.11 1.04 2.05 — — — 1.00 — 1.83 氧化镁 3.91 1.43 0.30 1.26 91.80 — — 0.31 0.40 0.13 0.02 0.40 水泥 25.74 10.96 3.14 48.24 — — — 6.16 4.03 — — 1.73 注：化学成分由X射线荧光光谱仪测得，“—”表示未测出。
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表 3 模型试验方案
Table 3 Plans of model tests
试验编号 土类 MgO掺量/% 初始含水率/% 通气压力/kPa 压实情况 #1 粉土 10 20 200 分层压实 #2 粉土 10 20 100 分层压实 #3 粉土 10 20 100 未压实 #4 淤泥质土 20 63 200 未压实 #5 淤泥质土 20 63 100 未压实
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表 4 单桩竖向抗压载荷试验结果
Table 4 Results of static load tests
桩 极限承载为/kN 桩顶位移/mm MCP-1 1800 19.04 MCP-2 1920 13.94 PHC 1400 11.97
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[1] AL-TABBAA A. Reactive Magnesia Cement[M]// Eco-Efficient Concrete. Amsterdam: Elsevier, 2013: 523-543.
[2] PHAN H Q H, HWANG K Y, AHN J Y, et al. Investigation of the accelerated carbonation of a MgO-based binder used to treat contaminated sediment[J]. Environmental Earth Sciences, 2017, 76(22): 771. doi: 10.1007/s12665-017-7115-6
[3] OLAJIRE A A. A review of mineral carbonation technology in sequestration of CO2[J]. Journal of Petroleum Science and Engineering, 2013, 109: 364-392. doi: 10.1016/j.petrol.2013.03.013
[4] PU L, UNLUER C. Investigation of carbonation depth and its influence on the performance and microstructure of MgO cement and PC mixes[J]. Construction and Building Materials, 2016, 120: 349-363. doi: 10.1016/j.conbuildmat.2016.05.067
[5] YI Y L, LU K W, LIU S Y, et al. Property changes of reactive magnesia-stabilized soil subjected to forced carbonation[J]. Canadian Geotechnical Journal, 2016, 53(2): 314-325. doi: 10.1139/cgj-2015-0135
[6] LIU S Y, CAI G H, CAO J J, et al. Influence of soil type on strength and microstructure of carbonated reactive magnesia-treated soil[J]. European Journal of Environmental and Civil Engineering, 2020, 24(2): 248-266. doi: 10.1080/19648189.2017.1378925
[7] CAI G H, LIU S Y. Compaction and mechanical characteristics and stabilization mechanism of carbonated reactive MgO-stabilized silt[J]. KSCE Journal of Civil Engineering, 2017, 21(7): 2641-2654. doi: 10.1007/s12205-017-1145-1
[8] HWANG K Y, KIM J Y, PHAN H Q H, et al. Effect of CO2 concentration on strength development and carbonation of a MgO-based binder for treating fine sediment[J]. Environmental Science and Pollution Research, 2018, 25(23): 22552-22560. doi: 10.1007/s11356-018-2338-y
[9] GALAN I, ANDRADE C, CASTELLOTE M. Natural and accelerated CO2 binding kinetics in cement paste at different relative humidities[J]. Cement and Concrete Research, 2013, 49: 21-28. doi: 10.1016/j.cemconres.2013.03.009
[10] YI Y L, LISKA M, UNLUER C, et al. Carbonating magnesia for soil stabilization[J]. Canadian Geotechnical Journal, 2013, 50(8): 899-905. doi: 10.1139/cgj-2012-0364
[11] YI Y L, LISKA M, AKINYUGHA A, et al. Preliminary laboratory-scale model auger installation and testing of carbonated soil-MgO columns[J]. Geotechnical Testing Journal, 2013, 36(3): 384-393. doi: 10.1520/GTJ20120052
[12] WANG D X, XIAO J, HE F J, et al. Durability evolution and associated micro-mechanisms of carbonated reactive MgO-fly ash solidified sludge from East Lake, China[J]. Construction and Building Materials, 2019, 208: 1-12. doi: 10.1016/j.conbuildmat.2019.02.173
[13] CAI G H, LIU S Y, ZHENG X. Effects of drying-wetting cycles on durability of carbonated reactive magnesia-admixed clayey soil[J]. Journal of Materials in Civil Engineering, 2019, 31(11): 84-93.
[14] CAI G H, LIU S Y, ZHENG X. Influence of drying-wetting cycles on engineering properties of carbonated silt admixed with reactive MgO[J]. Construction and Building Materials, 2019, 204: 84-93. doi: 10.1016/j.conbuildmat.2019.01.125
[15] 郑旭, 刘松玉, 蔡光华, 等. 活性MgO碳化固化土的冻融循环特性试验研究[J]. 东南大学学报(自然科学版), 2015, 45(3): 595-600. https://www.cnki.com.cn/Article/CJFDTOTAL-DNDX201503032.htm (ZHENG Xu, LIU Scongyu, CAI Guanghua, et al. Experimental study on freeze-thaw properties of carbonated reactive MgO-stabilized soils [J]. Journal of Southeast University Natural Science Edition, 2015, 45(3): 595-600. (in Chinese https://www.cnki.com.cn/Article/CJFDTOTAL-DNDX201503032.htm
[16] 刘松玉, 蔡光华. 碳化固化软弱土理论与技术[M]. 北京: 科学出版社, 2021. LIU Songyu, CAI Guanghua. Theory and Technology of Carbonation Curing Soft Soil[M]. Beijing: Science Press, 2021. (in Chinese)
[17] LIU S Y, CAI G H, DU G Y, et al. Field investigation of shallow soft-soil highway subgrade treated by mass carbonation technology[J]. Canadian Geotechnical Journal, 2021, 58(1): 97-113. doi: 10.1139/cgj-2020-0008
[18] 刘松玉, 蔡光华, 王亮, 等. 一种碳化搅拌桩-透气管桩复合地基及其施工方法: CN106869120B[P]. 2018-07-31. LIU Songyu, CAI Guanghua, WANG Liang, et al. Carbonization Mixing Pile-Ventilating Pipe Pile Composite Foundation and Construction Method Thereof: CN106869120B[P]. 2018-07-31. (in Chinese)
[19] 刘松玉, 席培胜, 储海岩, 等. 双向水泥土搅拌桩加固软土地基试验研究[J]. 岩土力学, 2007, 28(3): 560-564. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200703025.htm LIU Songyu, XI Peisheng, CHU Haiyan, et al. Research on practice of bidirectional deep mixing cement-soil columns for reinforcing soft ground[J]. Rock and Soil Mechanics, 2007, 28(3): 560-564. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200703025.htm
[20] LIU S Y, HRYCIW R D. Evaluation and quality control of dry-jet-mixed clay soil-cement columns by standard penetration test[J]. Transportation Research Record: Journal of the Transportation Research Board, 2003, 1849(1): 47-52. doi: 10.3141/1849-06
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