黄土抗震陷变形的酸改性方法及其微观结构分析
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摘要
低黏性粉质黄土的架空弱胶结微结构,导致这种黄土在动荷载作用下呈现出强度低、震陷变形大的现象,为黄土场地地基处理提出了挑战性的技术难题。黄土结构改性是通过改变其微观结构,达到有效降低震陷变形和湿陷性等为目的。本文采用酸改性方法处理黄土,即通过加入有较强分散和胶结效果的硼化合物作为主要改性物质;加入轻质碳酸钙等填料,调整原状土的颗粒粒径级配;以磷酸稀释液调解土的pH值。对改性土样进行震陷等试验测试对比,确定最佳配方,同时分析改性前后微观结构和能谱的变化。结果表明,酸改性方法能有效改善黄土的微观结构,使得土样的震陷变形系数明显降低。并且所添加的改性原料无毒,不会对土层产生污染。
The loess with low viscosity and large number of powder particles,has weak-cemented and more frame-holes microstructure,which could lower its dynamic strength and induce large seismic subsidence deformation under dynamic loading.It brings some challenges technology problems for foundation treatment in engineering construction.The acidified modification method is through by changing the loess microstructure from base to reduce its dynamic deformation and collapsibility.The modification method is by adding below,the boron chemical compound,the main materials can produce strong dispersed and cemented effect,light calcium carbonate,to adjust the original loess particles size gradation,and the diluted phosphoric acid,to adjust the original loess pH value.Moreover,through contrasting the seismic subsidence test and others by different ingredients,then analyzing its microstructure and energy spectrum before and after modification,the best proportion of ingredient is determined.The study results show that the acid-modified method can change the loess microstructure and reduce the seismic subsidence conefficients effectively.In addition,the all modified adding materials have non-toxic,and have no pollution to the soil.
The loess with low viscosity and large number of powder particles,has weak-cemented and more frame-holes microstructure,which could lower its dynamic strength and induce large seismic subsidence deformation under dynamic loading.It brings some challenges technology problems for foundation treatment in engineering construction.The acidified modification method is through by changing the loess microstructure from base to reduce its dynamic deformation and collapsibility.The modification method is by adding below,the boron chemical compound,the main materials can produce strong dispersed and cemented effect,light calcium carbonate,to adjust the original loess particles size gradation,and the diluted phosphoric acid,to adjust the original loess pH value.Moreover,through contrasting the seismic subsidence test and others by different ingredients,then analyzing its microstructure and energy spectrum before and after modification,the best proportion of ingredient is determined.The study results show that the acid-modified method can change the loess microstructure and reduce the seismic subsidence conefficients effectively.In addition,the all modified adding materials have non-toxic,and have no pollution to the soil.
引文
[1]王兰民.黄土动力学[M].北京:地震出版社,2003.
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[11]高国瑞.黄土湿陷结构分类及湿陷性[J].中国科学,1980,(12):1203-1208.GAO Guo-rui.The loess structure classification and itscollapsible characteristics[J].Chinese Science,1980,(12):1203-1208.
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[13]万玉珍,林德明.重塑黄土的应力-应变关系[J].岩土工程学报,1996,18(6):106-110.WAN Yu-zhen,LIN De-ming.The stress-strain relationof remodeling loess[J].Journal of GeotechnicalEngineering,1996,18(6):106-110.
[2]熊厚金,林天健,李宁.岩土工程化学[M].北京:科学出版社,2001.
[3]杨忠政.碳酸气硅化法加固关中黄土地的应用[C]//全国黄土学术会议文集.乌鲁木齐:新疆科技卫生出版社,1994:23-28.
[4]斐章勤.压密法灌浆处理湿陷性黄土黄土地基[C]//第四届地基处理学术讨论会论文集.杭州:浙江大学出版社,1995:35-42.
[5]邓安,肖杨,刘汉龙.砂-聚苯乙烯颗粒轻质填料工程特性试验研究[J].岩土工程学报,2008,30(8):1141-1145.DENG An,XIAO Yang,LIU Han-long.Engineeringbehavior of lightweight fills of sand-EPS beads[J].Chinese Journal of Geotechnical Engineering,2008,30(8):1140-1145.
[6]夏琼,杨有海,耿煊.粉煤灰与石灰、水泥改良黄土填料的试验研究[J].兰州交通大学学报,2008,27(3):40-43.XIA Qiong,YANG You-hai,GENG Xuan.Fly ash andlime,cement improvement of loess packing testresearch[J].Journal of Lanzhou Jiaotong University,2008,27(3):40-43.
[7]曹豪荣,李新明,樊友杰,等.考虑干湿循环路径的石灰改性红黏土路用性能试验研究[J].岩土力学,2012,33(9):2619-2624.CAO Hao-rong,LI Xin-ming,FAN You-jie,et al.Experimental study of pavement performances of lime-treated laterite soil considering drying-wetting cyclepaths[J].Rock and Soil Mechanics,2012,33(9):2619-2624.
[8]DENG Jin,WANG L M,ZHANG Z Z,et al.The loessmicrostructure characteristics and forming environment oflate Quaternary Period in the Loess Plateau of China[J].Environmental Earth Sciences,2010,59(8):1807-1817.doi:10.1007/s12665-009-0162-x.
[9]陕西省计划委员会.GB/J25-90湿陷性黄土地区建筑规范[S].北京:中国建筑出版社,1990.
[10]甘肃省建设科技专家委员会,中国地震局兰州地震研究所.DB62/T25-3037-2006兰州市区建筑抗震设计规程[S].兰州:甘肃省工程建设标准管理办公室,2007:12-13.
[11]高国瑞.黄土湿陷结构分类及湿陷性[J].中国科学,1980,(12):1203-1208.GAO Guo-rui.The loess structure classification and itscollapsible characteristics[J].Chinese Science,1980,(12):1203-1208.
[12]雷祥义.黄土显微结构类型与物理力学性质指标之间的关系[J].地质学报,1998,(2):182-190.LEI Xiang-yi.The relationship between the microfabrictypes and the indicies of physic–mechanical propertiesin loess of China[J].Acta Geologica Sinica,1998,(2):182-191.
[13]万玉珍,林德明.重塑黄土的应力-应变关系[J].岩土工程学报,1996,18(6):106-110.WAN Yu-zhen,LIN De-ming.The stress-strain relationof remodeling loess[J].Journal of GeotechnicalEngineering,1996,18(6):106-110.
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