Abstract
Grouting serves as an effective method for mitigating geotechnical disasters in subsea tunnels. However, current theories and designs, primarily based on terrestrial tunnel contexts, seldom address the long-term effects of seawater ion erosion on reinforcement. An improved sand permeation grouting simulation test system was employed to examine the mechanical property evolution of sand layer grouting reinforcement under seawater erosion, utilizing various grout types. The mechanical properties of grouting reinforcement, under varying curing conditions, were analyzed using uniaxial compression test, permeability test, and scanning electron microscope (SEM) test. Test results indicate that seawater curing conditions initially enhance the strength and impermeability of grouting reinforcement; however, prolonged curing diminishes these mechanical benefits. The onset of this process occurs significantly sooner in cement-sodium silicate grout (28d to 56d) compared to cement grout (56d to 90d). For cement grouting reinforcement, the deformation modulus increases over time, albeit at a decreasing rate. The deformation modulus of cement-sodium silicate grouting reinforcement follows an increase-decrease-increase pattern, correlating with the volume ratio over time. The decline in mechanical properties of grouting reinforcement during the test's mid to late stages under seawater conditions results from the interplay between erosive ions, which inhibit mechanical growth and accelerate deterioration.
Full Text
Study of Mechanical Properties of Sand Layer Grouting Reinforcement Under Seawater Erosion
Yunlong Wang¹, Yanxu Guo²,³*, Hongzhao Li⁴, Zhenjun Wang⁴, Peng Jiang⁵
¹ College of Architectural Engineering, Yangzhou Polytechnic Institute, Yangzhou 225127
² Weifang University, Weifang 261061
³ Geotechnical and Structural Engineering Research Center, Shandong University, Jinan 250061
⁴ Shandong Transportation Institute, Jinan 250104
⁵ Zaozhuang University, Zaozhuang 277160
Abstract
Grouting serves as an effective method for mitigating geotechnical disasters in subsea tunnels. However, existing theories and designs, which are primarily based on terrestrial tunnel conditions, rarely consider the long-term effects of seawater ion erosion on reinforcement performance. This study employed an improved sand permeation grouting simulation test system to investigate the evolution of mechanical properties in sand layer grouting reinforcement under seawater erosion, using various grout formulations. The mechanical properties of the grouting reinforcement under different curing conditions were evaluated through uniaxial compression testing, permeability testing, and scanning electron microscopy (SEM).
Results indicate that seawater curing initially enhances the strength and impermeability of grouting reinforcement, but prolonged exposure diminishes these mechanical benefits. The onset of this deterioration occurs significantly earlier in cement-sodium silicate grout (28d to 56d) compared to cement grout (56d to 90d). For cement grouting reinforcement, the deformation modulus increases over time, albeit at a decreasing rate. The deformation modulus of cement-sodium silicate grouting reinforcement exhibits an increase-decrease-increase pattern in relation to the volume ratio over time. The decline in mechanical properties during the mid-to-late stages of seawater curing stems from the combined action of erosive ions, which both inhibit mechanical enhancement and accelerate degradation.
Keywords: sand layer, grouting reinforcement, seawater erosion, mechanical properties, curing time