阳极灌浆溶液对电渗加固软土地基的影响
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摘要
为改善土体电渗处理效果,研究了电渗期间在阳极处添加化学试剂对地基加固处理的影响。试验采用自制模型箱,共设置5组试样,电势梯度为0.5 V·cm~(-1)。通过电渗过程中在土体与阳极电极板脱离处灌入等量氢氧化钠、氯化钠、氢氧化钙和氯化钙溶液,进行室内试验研究。试验控制添加的阴离子数量相同,钠溶液浓度为2.0 mol·L~(-1),钙溶液浓度为1.0 mol·L~(-1)。当电渗进行到15 h时,各试验组试样添加50 mL相应溶液。比较分析排水、电流、能耗及处理后抗剪强度、含水率、电导率等参数。试验结果表明:添加化学试剂能明显改善排水效果和土体强度,相比对照组,灌浆处理后抗剪强度提升了27.3%～44.6%,平均含水率降低了10.5%～34.7%;羟基与土体成分反应生成的物质填充孔隙,增大土体密实度和强度,同时会堵塞排水路径等;氯盐综合处理效果较好,但电极腐蚀和平均能耗较大;钙离子较钠离子能更好地改善排水和导电效果;在4种化学试剂中,氯化钙处理效果最佳。
To improve the effectiveness of electro-osmosis treatment of soil, the effects of adding chemical solutions during electro-osmosis on the reinforcement of a soil foundation were investigated. Self-made model boxes were used under an equal electric potential gradient of 0.5 V·cm ~(-1) to conduct an experimental investigation of anode grouting with different solutions. The solutions tested included sodium hydroxide, sodium chloride, calcium hydroxide, and calcium chloride, and were applied as grouting when the soil was separated from the anode plate. The number of anions added to each sample was equal. The concentration of the sodium solutions was 2.0 mol·L~(-1), and that of the calcium solutions was 1.0 mol·L~(-1). Each test sample was grouted with 50 mL of solution after 15 h. Parameters such as the electric current, drainage rate, and coefficient of energy consumption during the electro-osmosis process, as well as the moisture content, electrical conductivity, and shear strength after the tests were analyzed. The results show that adding a chemical solution can clearly improve the drainage and strength. Compared with the control group, the average moisture content decreases by more than 10.5% to 34.7%, while the shear strength increases by 27.3% to 44.6%. The substance produced by the reaction of hydroxyl groups with the soil-filled pores increases the compactness and strength but blocks drainage paths. The effects of treatment with the chloride solution are superior; however, the electrode corrosion and average energy consumption are greater than that of the alkali solution. Calcium ions are better than sodium ions for improving drainage and electrical conductivity. The treatment with calcium chloride is the most effective among the four types of chemical solutions tested.
To improve the effectiveness of electro-osmosis treatment of soil, the effects of adding chemical solutions during electro-osmosis on the reinforcement of a soil foundation were investigated. Self-made model boxes were used under an equal electric potential gradient of 0.5 V·cm ~(-1) to conduct an experimental investigation of anode grouting with different solutions. The solutions tested included sodium hydroxide, sodium chloride, calcium hydroxide, and calcium chloride, and were applied as grouting when the soil was separated from the anode plate. The number of anions added to each sample was equal. The concentration of the sodium solutions was 2.0 mol·L~(-1), and that of the calcium solutions was 1.0 mol·L~(-1). Each test sample was grouted with 50 mL of solution after 15 h. Parameters such as the electric current, drainage rate, and coefficient of energy consumption during the electro-osmosis process, as well as the moisture content, electrical conductivity, and shear strength after the tests were analyzed. The results show that adding a chemical solution can clearly improve the drainage and strength. Compared with the control group, the average moisture content decreases by more than 10.5% to 34.7%, while the shear strength increases by 27.3% to 44.6%. The substance produced by the reaction of hydroxyl groups with the soil-filled pores increases the compactness and strength but blocks drainage paths. The effects of treatment with the chloride solution are superior; however, the electrode corrosion and average energy consumption are greater than that of the alkali solution. Calcium ions are better than sodium ions for improving drainage and electrical conductivity. The treatment with calcium chloride is the most effective among the four types of chemical solutions tested.
引文
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[12] OU C Y, CHIEN S C, WANG Y G. On the Enhancement of Electroosmotic Soil Improvement by the Injection of Saline Solutions [J]. Applied Clay Science, 2009, 44 (1): 130-136.
[13] CHIEN S C, OU C Y, LEE Y C. A Novel Electroosmotic Chemical Treatment Technique for Soil Improvement [J]. Applied Clay Science, 2010, 50 (4):481-492.
[14] PENG J, YE H M, ALSHAWABKEH A N. Soil Improvement by Electroosmotic Grouting of Saline Solutions with Vacuum Drainage at the Cathode [J]. Applied Clay Science, 2015, 114: 53-60.
[15] 刘飞禹,王逸杰,王军.含易溶盐层状软黏土的电渗固结特性 [J].中国公路学报,2016,29(5):19-25,66. LIU Fei-yu, WANG Yi-jie, WANG Jun. Electro-osmotic Consolidation Property of Layered Soft Soil Containing Soluble Salt [J]. China Journal of Highway and Transport, 2016, 29 (5): 19-25, 66.
[16] LIU Fei-yu, FU Hong-tao, WANG Jiu, et al. Influence of Soluble Salt on Electro-osmotic Consolidation of Soft Clay [J]. Soil Mechanics & Foundation Engineering, 2017, 54 (1): 49-55.
[17] 刘剑,崔鹏.水土化学作用对土体黏聚力的影响——以蒙脱石-石英砂重塑土为例[J].岩土力学, 2017,38(2):419-427. LIU Jian, CUI Peng. Influence of Water-soil Chemical Interaction on Cohesive Force: A Case Study of Montmorillonite-Quartz Remolded Soil [J]. Rock and Soil Mechanics, 2017, 38 (2): 419-427.
[18] 杨爱武,闫澍旺,杜东菊,等.碱性环境对固化天津海积软土强度影响的试验研究[J].岩土力学,2010,31(9):2930-2934. YANG Ai-wu, YAN Shu-wang, DU Dong-ju, et al. Experimental Study of Alkaline Environment Effects on the Strength of Cement Soil of Tianjin Marine Soft Soil [J]. Rock and Soil Mechanics, 2010, 31 (9): 2930-2934.
[19] 李瑛,龚晓南,郭彪,等.电渗软黏土电导率特性及其导电机制研究[J].岩石力学与工程学报,2010,29(2):4027-4032. LI Ying, GONG Xiao-nan, GUO Biao, et al. Research on Conductivity Characteristics of Soft Clay during Electro-osmosis and Its Conductive Mechanism [J]. Chinese Journal of Rock Mechanics and Engineering, 2010, 29 (2): 4027-4032.
[20] OLANIIYAN O S, OLAOYE R A, OKEYINKA O M, et al. Soil Stabilization Techniques Using Sodium Hydroxide Additives [J]. International Journal of Civil & Environmental Engineering, 2011, 11 (6): 9-22.
[2] LIU Fei-yu, MI Wei, ZHANG Le, et al. Experimental Study of the Electro-osmosis Consolidation of Soft Clay Under Anode Follow-up [J]. Journal of Civil Architectural & Environmental Engineering, 2014, 3 (3): 176, 180-181, 184.
[3] CASAGRANDE I L. Electro-osmosis in Soils [J]. Geotechnique, 1949, 1 (1): 159-177.
[4] SAVEYN H, PAUWELS G, TIMMERMAN R, et al. Effect of Polyelectrolyte Conditioning on the Enhanced Dewatering of Activated Sludge by Application of an Electric Field During the Expression Phase [J]. Water Research, 2005, 39 (13): 3012-3020.
[5] GLENDINNING S, LAMONT-BLACK J, JONES C J F P, et al. Treatment of Lagooned Sewage Sludge in Situ Using Electrokinetic Geosynthetics [J]. Geosynthetics International, 2008, 15 (3): 192-204.
[6] ESTABRAGH A R, NASEH M, JAVADI A A. Improvement of Clay Soil by Electro-osmosis Technique [J]. Applied Clay Science, 2014, 95 (3): 32-36.
[7] YUAN J, MICHAEL A H. Numerical Simulation of Elasto-plastic Electro-osmosis Consolidation at Large Strain [J]. Acta Geotechnica, 2016, 11 (1): 127-143.
[8] GRAY D H, SCHLOCKER J. Electrochemical Alteration of Clay Soils [J]. Clays & Clay Minerals, 1969, 17 (5): 309-322.
[9] GRAY D H. Electrochemical Hardening of Clay Soils [J]. Geotechnique, 1970, 20 (1): 81-93.
[10] LEFEBVRE G, BURNOTTE F. Improvements of Electroosmotic Consolidation of Soft Clays by Minimizing Power Loss at Electrodes [J]. Canadian Geotechnical Journal, 2002, 39 (2): 399-408.
[11] BURNOTTE F, LEFEBVRE G, GRONDIN G. A Case Record of Electroosmotic Consolidation of Soft Clay with Improved Soil-electrode Contact [J]. Canadian Geotechnical Journal, 2004, 41 (6): 1038- 1053.
[12] OU C Y, CHIEN S C, WANG Y G. On the Enhancement of Electroosmotic Soil Improvement by the Injection of Saline Solutions [J]. Applied Clay Science, 2009, 44 (1): 130-136.
[13] CHIEN S C, OU C Y, LEE Y C. A Novel Electroosmotic Chemical Treatment Technique for Soil Improvement [J]. Applied Clay Science, 2010, 50 (4):481-492.
[14] PENG J, YE H M, ALSHAWABKEH A N. Soil Improvement by Electroosmotic Grouting of Saline Solutions with Vacuum Drainage at the Cathode [J]. Applied Clay Science, 2015, 114: 53-60.
[15] 刘飞禹,王逸杰,王军.含易溶盐层状软黏土的电渗固结特性 [J].中国公路学报,2016,29(5):19-25,66. LIU Fei-yu, WANG Yi-jie, WANG Jun. Electro-osmotic Consolidation Property of Layered Soft Soil Containing Soluble Salt [J]. China Journal of Highway and Transport, 2016, 29 (5): 19-25, 66.
[16] LIU Fei-yu, FU Hong-tao, WANG Jiu, et al. Influence of Soluble Salt on Electro-osmotic Consolidation of Soft Clay [J]. Soil Mechanics & Foundation Engineering, 2017, 54 (1): 49-55.
[17] 刘剑,崔鹏.水土化学作用对土体黏聚力的影响——以蒙脱石-石英砂重塑土为例[J].岩土力学, 2017,38(2):419-427. LIU Jian, CUI Peng. Influence of Water-soil Chemical Interaction on Cohesive Force: A Case Study of Montmorillonite-Quartz Remolded Soil [J]. Rock and Soil Mechanics, 2017, 38 (2): 419-427.
[18] 杨爱武,闫澍旺,杜东菊,等.碱性环境对固化天津海积软土强度影响的试验研究[J].岩土力学,2010,31(9):2930-2934. YANG Ai-wu, YAN Shu-wang, DU Dong-ju, et al. Experimental Study of Alkaline Environment Effects on the Strength of Cement Soil of Tianjin Marine Soft Soil [J]. Rock and Soil Mechanics, 2010, 31 (9): 2930-2934.
[19] 李瑛,龚晓南,郭彪,等.电渗软黏土电导率特性及其导电机制研究[J].岩石力学与工程学报,2010,29(2):4027-4032. LI Ying, GONG Xiao-nan, GUO Biao, et al. Research on Conductivity Characteristics of Soft Clay during Electro-osmosis and Its Conductive Mechanism [J]. Chinese Journal of Rock Mechanics and Engineering, 2010, 29 (2): 4027-4032.
[20] OLANIIYAN O S, OLAOYE R A, OKEYINKA O M, et al. Soil Stabilization Techniques Using Sodium Hydroxide Additives [J]. International Journal of Civil & Environmental Engineering, 2011, 11 (6): 9-22.
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