摘要
为了探讨改良黄土的抗剪强度特性及微观结构,开展了改性纤维素和生石灰改良黄土在不同含水率、压实度下的直剪试验,并对不同压实度下的改良黄土进行微观结构试验研究。试验结果表明:改良黄土的粘聚力和内摩擦角较重塑黄土均有提升,并受到压实度和含水量的影响,当压实度为90%时,纤维素改良黄土和石灰改良黄土粘聚力分别提高了87.86%和234.90%,内摩擦角分别提高了5.37%和14.02%。随压实度的增加,3种黄土大中孔隙数目占比逐渐减小,微小孔隙面积占比不断增多,且微小孔隙数目占比远大于大中孔隙,面孔隙率也随压实度的增大而减小,且与大中孔隙面积有关。在同一压实度下,改性纤维素改良黄土和石灰改良黄土较重塑黄土颗粒紧密接触,结构更加稳定;微小孔隙数目增加,而大中孔隙减小;面孔隙率也减小,以压实度90%为例,改性纤维素和石灰改良黄土分别减少了32.37%和43.10%,使得改良黄土抗剪强度提高、石灰改良最明显。研究成果可为黄土地区填方边坡土体改良提供技术支持。
In order to study the shear strength characteristics and microstructure of modified loess, the direct shear tests of modified cellulose and quicklime modified loess under different moisture content and compactness were carried out, and the microstructure of modified loess under different compactness was studied.The test results show that the cohesion and internal friction angle of the improved loess are higher than those of the remolded loess, and are affected by the degree of compaction and water content. When the degree of compaction is 90%, the cohesion of the cellulose improved loess and the lime improved loess are increased by 87.86% and 234.90% respectively, and the internal friction angle is increased by 5.37% and 14.02% respectively. With the increase of compaction degree, the proportion of large and medium-sized pores in the three loess types gradually decreases, and the proportion of micro pore area continues to increase, and the proportion of micro pore number is much larger than that of large and medium-sized pores. The face porosity also decreases with the increase of compaction degree, and is related to the area of large and medium-sized pores. At the same degree of compaction, the modified cellulose loess and lime loess are in close contact with each other, and their structures are more stable than that of remolded loess;The number of micro pores increases, while the large and medium pores decrease;The surface porosity also decreased. Taking the compaction degree of 90% as an example, the modified cellulose and lime improved loess decreased by 32.37% and 43.10% respectively, making the shear strength of the improved loess increased and lime improved most obviously. The research results can provide technical support for soil improvement of fill slope in loess region.
作者
陈林万
曹玉桃
杜杰
张晓超
裴向军
CHEN Lin-wan;CAO Yu-tao;DU Jie;ZHANG Xiao-chao;PEI Xiang-jun(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China;Jiuzhaigou Scenic Spot Administration Bureau,Aba 623402,China)
出处
《地质灾害与环境保护》
2022年第4期41-50,共10页
Journal of Geological Hazards and Environment Preservation
基金
国家自然科学基金重大项目(41790445)资助。
关键词
改性纤维素
生石灰
改良黄土
抗剪强度
微观结构
modified cellulose
quicklime
improved loess
shear strength
microstructure
