木质素纤维黄土渗透性能影响因素研究

Study on the Influencing Factors of Permeability of Lignin Fiber Improved Loess

为了研究木质素纤维作为改良材料时木质素纤维黄土的渗透特征,通过恒水头三轴渗透试验和扫描电镜试验对不同木质素掺量(掺量为1%、3%、5%和7%)和养护龄期(龄期为0 d、3 d、7 d和28 d)的木质素纤维黄土进行试验,探讨不同条件时木质素纤维黄土的渗透性及微观差异。试验结果表明:木质素纤维黄土的渗透系数随养护龄期增加先增大后减小(趋于稳定),部分后期又增大;施加的围压越大,试样的渗透系数越小;木质素纤维掺量为3%时,渗透系数最小,木质素纤维掺量在1%~7%范围内,渗透系数先减小后增大;木质素纤维掺量越多,木质素纤维间聚集现象更明显,掺量较小时黄土与木质素纤维的复合效果越好。对木质素纤维黄土渗透性影响因素的显著性顺序为木质素纤维掺量>围压>养护龄期。

To evaluate the permeability characteristics of loess when using lignin fiber as an improved material,the constant head triaxial penetration test and scanning electron microscope test were conducted to explore the permeability and microscopic differences of lignin fiber improved loess under different conditions,considering different lignin content(the content is 1%,3%,5%and 7%)and the curing age(the age is 0 d,3 d,7 d and 28 d).The test results show that the curing age affects the bonding degree of the loess and the lignin fiber composite,the permeability coefficient increased first and then decreased(tended to be stable)with the increase of the curing age,and some results increased in later stages.The confining pressure gradually increased during the test,and the permeability coefficient of the sample decreased.When the content of lignin fiber is 3%,the permeability coefficient was the smallest,indicating that the permeability coefficient first decreased and then increased within the range of 1%~7%of the lignin fiber content.The content of lignin fiber blended in loess increases,and the lignin fibers are closely connected with each other.When the content of lignin fiber decreased,the composite effect between loess and lignin fibers became better than before.The significant order of influencing factors on the permeability of lignin fiber improved loess is lignin fiber content,confining pressure and curing age.