Study on Composite Improvement of Silt Sites by Lignin and Sodium Methylsilicate and Its Micro Mechanism

Abstract

Kaifeng Zhouqiao site is located in the traffic trunk line in Gulou District of Kaifeng City. The dynamic load of urban traffic is large. In addition, the silt has poor stability of its particle skeleton structure, large porosity and poor mechanical performance. Under the action of dynamic load, the soil of the site will suffer from cracking, collapse, unstable deformation and overall stability damage. In order to enhance the stability of the soil, this paper uses sodium methylsilicate and lignin fiber to modify the site soil, evaluates the mechanical properties of the improved soil through the compression and shear tests, evaluates the durability of the improved soil through the dry wet cycle test, and reveals its modification mechanism through the micro experiment, so that the mechanical properties of the site soil can be improved, so as to achieve the purpose of repair and reinforcement. The experiment shows that the effect of improving the compressive strength of soil is the best when the content of sodium methylsilicate is 0.3%–0.5%, and the effect of improving the shear strength of soil is the best when the content of lignin is 0.5%–2%. The maximum mass loss rate of the composite modified sample after 10 dry and wet cycles is only 0.71%. The comprehensive analysis determines that the best proportion of the composite is 0.5% sodium methylsilicate and 2% lignin fiber. The modified soil has good waterproof and mechanical properties.