改性纳米硅材料加固松散砂土的工程特性研究
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摘要
为了改变松散砂土的低强度和低抗侵蚀性,本文以纳米硅材料为基础,采用聚丙烯酰胺类作为改性剂,对松散砂土进行加固研究。分别研究在不同浓度的纳米硅材料以及不同掺量的改性剂的共同作用下,加固松散砂土的无侧限抗压强度、抗剪强度以及其崩解特性的变化规律,并对其加固机理进行分析。试验结果表明,改性后的纳米硅材料对松散砂土的无侧限抗压强度、抗剪强度以及抗崩解能力都得到较大的提高。当纳米硅材料浓度一定时,砂土的抗压强度和抗剪强度随着改性剂掺量的增加出现先增大后减小的趋势;在纳米硅浓度20%、改性剂掺量0. 2%时抗压强度达到最大值970 k Pa;在纳米硅浓度20%,改性剂掺量0. 3%时黏聚力和摩擦角分别为173. 2 k Pa和39. 3°;在加固松散砂土的抗崩解试验中,当纳米硅浓度大于20%、改性剂掺量大于0. 1%时,加固后的砂土在水中侵泡8 d后砂样的崩解率低于50%;当纳米硅浓度20%,改性剂掺量0. 2%时,加固砂土不崩解。综合试验结果,建议纳米硅溶液的浓度在20%,改性剂的掺量为0. 2%作为改性纳米硅材料加固松散砂土的最优配比。
In order to change the low strength and low erosion resistance of loose sand,the reinforcement of loose sand is exaimed in this paper,which is based on nano-silicon material and takes polyacrylamide as modifier. Under the joint action of different concentrations of nano-silicon material and different amount of modifier,the unconfined compressive strength,shear strength and disintegration characteristics of the the consolidated loose sand are studied respectively, and the reinforcement mechanism is analyzed. The experimental results show that the unconfined compressive strength,shear strength and anti-disintegration ability of the modified nano-silica material are greatly improved. When the concentration of nano-silicon is constant,the compressive strength and shear strength of sand increase at first and then decrease with the increasing modifier content. When the concentration of nano-silicon is 20% and the amount of modifier is 0.2%,the compressive strength reaches the maximum 970 kPa. When the concentration of nano-silicon is 20%and the amount of modifier is 0. 3%,the adhesion force and friction angle are 173. 2 k Pa and 39. 3 °,respectively. In the anti-disintegration test of the consolidated loose sand,when the concentration of nanosilicon is more than 20% and the amount of modifier is more than 0. 1%,the disintegration rate of the reinforced sand sample is less than 50% after 8 days of invading in water. When the concentration of nanosilicon is 20% and the amount of modifier is 0. 2%,the stabilized sand will not disintegrate. Comprehensive test results suggest that the concentration of nano-silicon solution of 20% and the amount of modifier of 0. 2%are the best proportions of the modified nano-silicon material to strengthen loose sand.
In order to change the low strength and low erosion resistance of loose sand,the reinforcement of loose sand is exaimed in this paper,which is based on nano-silicon material and takes polyacrylamide as modifier. Under the joint action of different concentrations of nano-silicon material and different amount of modifier,the unconfined compressive strength,shear strength and disintegration characteristics of the the consolidated loose sand are studied respectively, and the reinforcement mechanism is analyzed. The experimental results show that the unconfined compressive strength,shear strength and anti-disintegration ability of the modified nano-silica material are greatly improved. When the concentration of nano-silicon is constant,the compressive strength and shear strength of sand increase at first and then decrease with the increasing modifier content. When the concentration of nano-silicon is 20% and the amount of modifier is 0.2%,the compressive strength reaches the maximum 970 kPa. When the concentration of nano-silicon is 20%and the amount of modifier is 0. 3%,the adhesion force and friction angle are 173. 2 k Pa and 39. 3 °,respectively. In the anti-disintegration test of the consolidated loose sand,when the concentration of nanosilicon is more than 20% and the amount of modifier is more than 0. 1%,the disintegration rate of the reinforced sand sample is less than 50% after 8 days of invading in water. When the concentration of nanosilicon is 20% and the amount of modifier is 0. 2%,the stabilized sand will not disintegrate. Comprehensive test results suggest that the concentration of nano-silicon solution of 20% and the amount of modifier of 0. 2%are the best proportions of the modified nano-silicon material to strengthen loose sand.
引文
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[2]许冲,王世元,徐锡伟,等. 2017年8月8日四川省九寨沟M_S7. 0地震触发滑坡全景[J].地震地质,2018,40(1):232-260.[XU C,WANG S Y,XU X W,et al. A panorama of landslides triggered by the August 8,2017,Jiuzhaigou M_S7. 0 earthquake in Sichuan[J]. Seismology and Geology,2018,40(1):232-260.(in Chinese)]
[3] KUKAL S S,KAUR M,BAWA S S,et al. Water-drop stability of PVA-treated natural soil aggregates from different land uses[J]. Catena,2007,70(3):475-479.
[4]李建法,宋湛谦.木质素磺酸盐及其接枝产物作沙土稳定剂的研究[J].林产化学与工业,2002,22(1):17-20.[LI J F,SONG Z Q. Study on lignosulfonate and its grafted product as sand stabilizer[J]. Chemistry and Industry of Forest Products,2002,22(1):17-20.(in Chinese)]
[5]刘瑾,陈晓明,张峰君,等.高分子土固化剂的合成及固化机理研究[J].材料科学与工程,2002,20(2):230-234.[LIU J,CHEN X M,ZHANG F J,et al. Study on synthesis and solidification mechanism of the polymer soil consolidator[J]. Materials Science&Engineering,2002,20(2):230-234.(in Chinese)]
[6]唐朝生,施斌,蔡奕,等.聚丙烯纤维加固软土的试验研究[J].岩土力学,2007,28(9):1796-1800.[TANG C S,SHI B,CAI Y,et al. Experimental study on polypropylene fiber improving soft soils[J].Rock and Soil Mechanics,2007,28(9):1796-1800.(in Chinese)]
[7]王银梅,孙冠平,谌文武,等. SH固沙剂固化沙体的强度特征[J].岩石力学与工程学报,2003,22(增刊2):2883-2887.[WANG Y M,SUN G P,CHEN W W,et al. Strength characteristics of sand fixated by SH[J]. Chinese Journal of Rock Mechanics and Engineering,2003,22(Sup 2):2883-2887.]
[8]冯巧,刘瑾,卢毅,等.一种复合加固剂改良砂土的强度试验研究[J].工程地质学报,2017,25(4):903-911.[FENG Q, LIU J, LU Y, et al.Experimental study on strength of sand reinforced with composite reinforcement agent[J]. Journal of Engineering Geology,2017,25(4):903-911.(in Chinese)]
[9]卜思敏.纳米硅溶胶固化黄土的强度特性及其固化机理[D].兰州:兰州大学,2016.[BU S M.Strength characteristics and modification theory of loess modified by Nano silica sol[D]. Lanzhou:Lanzhou University,2016.(in Chinese)]
[10]樊恒辉,赵高文,孔令伟,等.一种测定土体湿化、崩解与分散的试验方法:中国,201210001204. 8[P]. 2012-07-11.[FAN H H,ZHAO G W,KONG L H,et al. A test method for determination of soil moisture,disintegration and dispersion:China,201210001204. 8[P]. 2012-07-11.(in Chinese)]
[11]谷天峰,袁亮,胡炜,等.黑方台黄土崩解性试验研究[J].水文地质工程地质,2017,44(4):62-70.[GU T F,YUAN L,HU W,et al. Experimental research on disintegration of the Heifangtai loess[J].Hydrogeology&Engineering Geology,2017,44(4):62-70.(in Chinese)]
[12]曾庆建,刘宝臣,张炳晖,等.红黏土崩解特性试验研究[J].水文地质工程地质,2018,45(3):93-97.[ZENG Q J,LIU B C,ZHANG B H,et al. An experimental study of the disintegration characteristics of red clay[J]. Hydrogeology&Engineering Geology,2018,45(3):93-97.(in Chinese)]
[13]裴向军,罗阳楚君,杨晴雯.含水率及掺砂量对双聚材料改良碎石土性能的影响[J].重庆交通大学学报(自然科学版),2018,37(9):48-52.[PEI X J,LUO Y C J,YANG Q W,et al. Impact of water content and sand content on performance of improved gravel soil with dimeric materials[J]. Journal of Chongqing Jiaotong University(Natural science),2018,37(9):48-52.(in Chinese)]
[14]刘彤彤. HPMC改性硅溶胶/聚丙烯酸酯杂化乳液的合成与性能研究[D].广州:华南理工大学,2015.[LIU T T. Synthesis and properties of HPMC modified Silica-Sol/Polyacrylate hybrid emulsion[D]. Guangzhou:South China University of Technology,2015.(in Chinese)]
[15]黄英,符必昌.土壤强固剂加固红土的力学特性[J].水文地质工程地质,2002,29(5):4-6.[HUANG Y,FU B C. Mechanical properties of the soil-solidified additive on the strengthening of laterite[J]. Hydrogeology&Engineering Geology,2002,29(5):4-6.(in Chinese)]
[16]黄河,施斌,刘瑾,等. STW型生态土壤稳定剂改性膨胀土水理性质试验研究[J].岩土工程学报,2008,30(8):1236-1240.[HUANG H,SHI B,LIU J,et al. Water-physical properties of expansive soils modified by STW ecotypic soil stabilizer[J].Chinese Journal of Geotechnical Engineering,2008,30(8):1236-1240.(in Chinese)]
[17]王许诺,杨平,鲍俊安,等.冻结水泥土无侧限抗压试验研究[J].水文地质工程地质,2013,40(3):79-83.[WANG X N,YANG P,BAO J A,et al. Test research on unconfined compressive strength of freezing cement soil[J]. Hydrogeology&Engineering Geology,2013,40(3):79-83.(in Chinese)]
[18]束华东,李小红,张治军.表面修饰纳米二氧化硅及其与聚合物的作用[J].化学进展,2008,20(10):1509-1514.[SHU H D,LI X H,ZHANG Z J. Surface modified nano-silica and its action on polymer[J]. Progress in Chemistry,2008,20(10):1509-1514.(in Chinese)]
[19]邢鲜丽,李同录,李萍,等.黄土抗剪强度与含水率的变化规律[J].水文地质工程地质,2014,41(3):53-59.[XING X L,LI T L,LI P,et al. Variation regularities of loess shear strength with the moisture content[J]. Hydrogeology&Engineering Geology,2014,41(3):53-59.(in Chinese)]