Research On The Mechanical Properties Of Lime-Calcium Lignosulfonate Stabilized Loess

Loess is widely distributed in China and has low bearing capacity,high compressibility and water sensitivity.When it is directly used as subgrade filler,it cannot meet the engineering requirements.Therefore,it is necessary to stabilize loess.The research object in this paper was the loess collected from Lanzhou city,and lime and calcium lignosulfonate were applied as binders to explore the mechanical properties of stabilized loess.The unconfined compressive strength test,California bearing ratio test and resilience modulus test were used to study the effects of curing age and calcium lignosulfonate content on unconfined compressive strength,CBR and resilience modulus of stabilized loess,and fitting regression analysis was carried out on the test data.The research results are as follows:(1)The results of unconfined compressive strength test of stable loess show that The unconfined compressive strength of calcium lignosulfonate stabilized loess increases first and then decreases with the increase of calcium lignosulfonate content.When the content of calcium lignosulfonate is less than 1%,the unconfined compressive strength of stable loess will increase with the increase of age.When the amount of curing agent exceeds 1%,the unconfined compressive strength of stabilized loess will decrease with the increase of age due to the“lubrication effect”of calcium lignosulfonate.The unconfined compressive strength of 3%lime-calcium lignosulfonate stabilized loess increases first and then decreases with the increase of calcium lignosulfonate content.The unconfined compressive strength of 3%lime-calcium lignosulfonate stabilized loess will increase with the increase of curing age.The relationship between unconfined compressive strength and curing age of stabilized loess is fitted and analyzed by hyperbolic function.The correlation coefficient R~2 of the fitted hyperbolic function is greater than 0.85,which can provide reference for engineering practice.(2)The CBR test shows that the CBR of calcium lignosulfonate stabilized loess increases first and then decreases with the increase of calcium lignosulfonate content.The CBR of 0.5%and 1%calcium lignosulfonate stabilized loess will increase with the increase of curing age,and the CBR of stabilized loess will decrease with the increase of curing age when the dosage is higher than 1%.The CBR of 3%lime-calcium lignosulfonate stabilized loess decreases with the increase of calcium lignosulfonate content and increases with the increase of curing age.The functional relationship between CBR and curing age of stable loess was established by fitting the experimental data.The quantitative relationship between the unconfined compressive strength and CBR of stable loess was established by fitting regression.(3)The resilience modulus test results of stable loess samples shows that the resilience modulus of calcium lignosulfonate and 3%lime-calcium lignosulfonate stabilized loess increases first and then decreases with the increase of calcium lignosulfonate content,and its resilience modulus increases with the increase of age.By fitting the experimental data,it is found that there is a good linear relationship between the unit pressure and the rebound deformation of the stable loess,and the prediction formula of the resilience modulus is established.The relationship between unconfined compressive strength and resilience modulus was established by regression analysis of the mechanical indexes of stable loess.Through the comprehensive analysis of unconfined compressive strength,CBR and resilience modulus of stabilized loess,the optimal ratio of calcium lignosulfonate and 3%lime-calcium lignosulfonate in loess subgrade reinforcement is 1%and 3%+0.5%respectively.The quantitative relationship between curing age,calcium lignosulfonate content and unconfined compressive strength,CBR and resilience modulus was established,which provided reference for the design and construction quality inspection of solidified loess subgrade.