摘要
为了探究硫酸盐粉质黏土的变形规律和力学特性,对常温、冻结两种情况下不同硫酸钠盐含量的粉质黏土进行了三轴剪切试验与改良试验。基于试验数据,作出了常温、冻结条件工况下试样的应力-应变关系曲线。选取不同含盐量试样在线弹性阶段临界点的切向模量,确定了含盐量与切向模量间的关系,提出了常温硫酸钠盐粉质黏土的摩尔-库仑参数计算公式,通过试验数据拟合了常温试样的摩尔-库仑参数。参考Duncan-Chang土体应力-应变曲线模型,推导了冻结硫酸钠盐粉质黏土轴向应变与轴向应变/偏应力间的线性关系,并对相关强度参数进行了拟合。建立了非线性强度准则描述应力-应变变化规律,研究了无水Ca(OH)_(2)和木质纤维含量对硫酸钠盐粉质黏土的强度影响变化规律。结果表明:常温、冻结两种情况下硫酸钠盐粉质黏土的应力-应变曲线均为应变软化型曲线,常温试样的破坏强度随围压的增大而增大,随含盐量的增大先增大后减小;冻结试样的破坏强度随冻结温度的降低而增大,随含盐量的增加而减小;提出的强度准则公式能较好描述不同工况下的硫酸钠盐粉质黏土的变形规律;无水Ca(OH)_(2)和木质纤维均能有效改良硫酸钠盐粉质黏土的工程性质,添加无水Ca(OH)_(2)和木质纤维能使试样强度提升15%~20%。
In order to study the deformation rule and mechanical properties of sodium sulfate silty clay,the triaxial shear test and improvement test of the silty clay with different sodium sulfate contents under the conditions of normal temperature and frozen are carried out.Based on the experimental data,the stress-strain curves of the samples under such conditions are drawn.Selecting the tangential modulus of the samples with different salt contents at critical point,the relationship between the salt content and tangential modulus is determined,the formula for calculating the Mohr-Coulomb parameters of sodium sulfate silty clay at normal temperature is proposed,and the Mohr-Coulomb parameters of the samples at normal temperature are fitted by using the experimental data.Referring to the Duncan-Chang soil stress-strain curve model,the linear relationship between the axial strain and the axial strain/partial stress of the frozen sodium sulfate silty clay is derived,and the relevant strength parameters are fitted.The nonlinear strength criterion is established to describe the stress-strain variation rule,and the influence rules of anhydrous Ca(OH)-(2)and woody fiber contents on the strength of sodium sulfate salt silty clay are studied.The result shows that(1)the stressstrain curves of the sodium sulfate silty clay under the conditions of normal temperature and frozen are strain softening curves,the failure strength of the samples at normal temperature increases with the increase of confining pressure,and first increases and then decreases with the increase of sodium sulfate content;(2)the failure intensity of the frozen samples increases with the decrease of freezing temperature and decreases with the increase of sodium sulfate content;(3)the proposed strength criterion formula can better describe the deformation rule of sodium sulfate silty clay under different working conditions;(4)anhydrous Ca(OH)_(2)and wood fiber can effectively improve the engineering properties of sodium sulfate silty clay,the addition of anhydrous
作者
万旭升
颜梦宇
路建国
晏忠瑞
刘凤云
WAN Xu-sheng;YAN Meng-yu;LU Jian-guo;YAN Zhong-rui;LIU Feng-yun(School of Civil Engineering and Geomatics,Southwest Petroleum University,Chengdu Sichuan 610500,China)
出处
《公路交通科技》
CSCD
北大核心
2023年第9期63-74,共12页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(42071087,42271146)
四川省科技计划项目(2021YFQ0021)
冻土工程国家重点实验室开放基金项目(SKLFSE202007)。
