摘要
为研究地聚合物固化含黏风积沙的持水性能,采用地聚合物对含黏风积沙进行改良,基于压力板仪法测量了不同基质吸力下对应的体积含水率,绘制了相应的土-水特征曲线(SWCC)并进行了模型拟合,探讨了含黏量、地聚合物掺量、龄期和纤维长度对固化风积沙持水性能和拟合参数的影响规律。研究结果表明:随着含黏量由20%提升到30%,风积沙试样在同一吸力下的体积含水率上升了3%左右,持水性显著提升;随着地聚合物掺量由8%提升到12%,20%和30%含黏量固化风积沙SWCC整体上移,10 kPa吸力对应体积含水率分别提升7.0%和5.9%,600 kPa吸力对应体积含水率分别提升4.3%和4.2%;而延长龄期对固化风积沙持水性能的提升较小,体积含水率变化幅度不超过1%;长度为6 mm的玄武岩纤维对固化风积沙持水性能的提升很小,但掺入长度为12 mm的纤维会导致其持水性能稍降低,两者变化幅度均不超过1%;固化含黏风积沙的SWCC具有2个陡降段,可采用分段式Van Genuchten模型拟合;双峰拟合参数能够反映试样大、小孔隙的分布,黏土仅影响大孔隙参数,而地聚合物能够影响大、小孔隙参数;扫描电镜和压汞试验结果表明地聚合物胶结产物和黏土的填充作用降低了土样孔隙率,掺入地聚合物后固化风积沙中孔隙总体积变化较小,一些大孔隙转化为小孔隙,大孔隙峰值密度由0.45 mL·g^(-1)降至0.22 mL·g^(-1),微孔隙峰值密度由0.02 mL·g^(-1)升至0.05 mL·g^(-1),孔隙平均尺寸减小;地聚合物水化产物的胶结作用导致土中产生团聚体,包裹了部分自由水并阻碍了水分流失,进而提高了固化风积沙的整体持水性能。
In order to study the water retention capacity of geopolymer stabilized aeolian sand with clay,the geopolymer was used to stabilize the aeolian sand with clay.Based on the pressure plate instrument method,the volume water contents under different matric suctions were measured,and the soil-water characteristic curves(SWCC)of stabilized aeolian sand were drawn and fitted.The effects of clay content,geopolymer content,curing time,and fiber length on the water retention capacity and fitting parameters of stabilized aeolian sand were studied.Research results show that with the increase in the clay content from 20%to 30%,the volume water content of aeolian sand sample under the same suction increases by about 3%,and the water retention capacity increases significantly.With the increase in the geopolymer content from 8%to 12%,the SWCCs of stabilized aeolian sand with 20%and 30%clay show an overall upward-moving trend,and the corresponding volume water contents with 10 kPa suction increase by 7.0%and 5.9%,and the corresponding volume water contents with 600 kPa suction increase by 4.3%and 4.2%,respectively.However,the extension of curing time has little effect on the improvement of the water retention capacity of stabilized aeolian sand,and the change range of volume water content is less than 1%.Basalt fiber with a length of 6 mm can barely improve the water retention capacity of stabilized aeolian sand.But increasing the fiber length to 12 mm slightly decreases the water retention capacity of stabilized aeolian sand,and the change ranges of both are less than 1%.The SWCC of stabilized aeolian sand with clay has two steep drop sections,which can be fitted by the multi-segment Van Genuchten model.The bimodal fitting parameters can reflect the distributions of large and small pores of the samples.Clay can only affect the parameters of large pores,while the geopolymer can affect the parameters of large and small pores.The scanning electron microscope and the mercury intrusion porosimetry test results show that the filling effects of geopolymer gel and clay reduce the porosity of soil samples.The overall pore volume in the stabilized aeolian sand varies slightly after the geopolymer is added.However,parts of the large pores change into small pores,the peak density of large pores decreases from 0.45 mL·g^(-1)to 0.22 mL·g^(-1),the peak density of micro pores increases from 0.02 mL·g^(-1)to 0.05 mL·g^(-1),and the average pore size decreases.The cementation of geopolymer leads to the formation of aggregates in the soil,which encapsulates some of the free water and prevents the water loss,improving the overall water retention capacity of stabilized aeolian sand.
作者
陈锐
陈海
包卫星
来弘鹏
CHEN Rui;CHEN Hai;BAO Wei-xing;LAI Hong-peng(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China)
出处
《交通运输工程学报》
EI
CSCD
北大核心
2023年第4期128-141,共14页
Journal of Traffic and Transportation Engineering
基金
国家自然科学基金项目(51708041)
陕西省自然科学基金项目(2022JM-228)
中央高校基本科研业务费专项资金项目(300102210213)
关键词
路基工程
风积沙路基
土-水特征曲线
地聚合物
含黏量
玄武岩纤维
subgrade engineering
aeolian sand subgrade
soil-water characteristic curve
geopolymer
clay content
basalt fiber
作者简介
陈锐(1987-),男,广西来宾人,长安大学副教授,工学博士,从事特殊土力学特性和地基处理研究。
