摘要
为了提升干湿循环下膨胀土的抗剪强度及抗衰减能力,采用甲基硅酸钠与木质素纤维进行复合改良。确定最佳掺量后,对改良土进行0、1、3、6、9次干湿循环,开展固结不排水三轴试验,分析应力-应变关系,获取并分析邓肯-张模型参数。结果表明:改良剂有效抑制了土体胀缩,抗剪强度随干湿循环次数先增后减,6次后趋于稳定;同时,通过曲面拟合,建立了初始切线弹性模量E_(i)和极限主应力差(σ_(1)-σ_(3))_(ult)随干湿循环次数N和围压σ_(3)变化的公式;验证了邓肯-张模型能较好模拟改良土在干湿交替下的应力-应变关系;甲基硅酸钠木质素纤维复合改良可以提升膨胀土在干湿环境下的力学性质,验证的模型证实了邓肯-张模型在改良土工程应用中的可靠性,为模拟干湿交替中的土体强度衰减提供了有效方法。
To enhance the shear strength and resistance to strength degradation of expansive soil under dry-wet cycles,a composite modification is employed using sodium sodium methyl silicate and lignin fiber.After determining the optimal dosage,modified soil specimens undergo 0,1,3,6,and 9 dry-wet cycles.Consolidated undrained triaxial tests are then conducted to analyze the stress-strain relationships and obtain Duncan-Chang model parameters.The results show that the modifiers effectively inhibit the swelling and shrinkage of the soil.The shear strength of the modified soil initially increases and then decreases with the number of dry-wet cycles,tending to stabilize after 6 cycles.Furthermore,through surface fitting,formulas describing how the initial tangent elastic modulus(E_(i))and the ultimate principal stress difference((σ_(1)-σ_(3))_(ult))vary with the number of dry-wet cycles(N)and the confining pressure(σ_(3))are established.The Duncan-Chang model is validated to effectively simulate the stress-strain relationship of the modified soil under alternating dry-wet conditions.Therefore,composite modification with sodium sodium methyl silicate and lignin fiber can improve the mechanical properties of expansive soil in dry-wet environments.The validated model confirms the reliability of the Duncan-Chang model for engineering applications involving modified soils and provides an effective method for simulating strength degradation in soils subjected to alternating dry-wet conditions.
作者
汤瑷玮
肖桂元
杨敦汉
TANG Aiwei;XIAO Guiyuan;YANG Dunhan(Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin Guangxi 541004,China;Key Laboratory of Green Building Materials and Building Industrialization,Guilin University of Technology,Guilin Guangxi 541004,China)
出处
《兰州工业学院学报》
2026年第1期69-74,共6页
Journal of Lanzhou Institute of Technology
基金
国家自然科学基金(2169022)。
关键词
膨胀土
甲基硅酸钠
木质素纤维
抗剪强度
干湿循环
邓肯-张模型参数
expansive soil
sodium methyl silicate
lignin fibers
shear strength
wet-dry cycles
Duncan-Chang model parameters
