The prestressed glass fiber-reinforced polymer (GFRP) rock bolt, characterized by its lightweight, high-strength, fatigue-resistant, and corrosion-resistant, effectively addresses the durability challenges associated with rock bolts in soil applications. This study was based on the shear test of GFRP anchor rods under varying levels of prestressing. The present study designed and conducted shear tests on GFRP anchor bolt joint surfaces under varying prestress levels, utilizing the double shear test method. Based on the experimental results, this research analyzed the influence of prestress on failure modes, shear bearing capacity, and shear deformation of GFRP anchor bolt joint surfaces. Furthermore, by employing an equivalent strain assumption in conjunction with damage mechanics theory, a predictive model for shear displacement-shear stiffness and shear displacementshear stress was established for GFRP anchor bolts. The results indicated that the failure mode of the prestressed GFRP anchor rod joint surface shear specimen was the shear failure following the splitting of the GFRP anchor rod. The shear carrying capacity of the joint surface with 20 % and 40 % pre-stressed GFRP anchor rods increased by 8.2 % and 20.3 % compared to the non-prestressed anchor rod, respectively. However, the ultimate displacements decreased by 22.7 % and 49.7 %, respectively. The initial stiffness of the 20 % and 40 % prestressed GFRP anchor rods was higher than that of non-prestressed GFRP anchor rods. However, under shear loading, the fracture strain of prestressed GFRP anchor rods decreased by 33 % and 44 %, respectively, compared to non-prestressed counterparts. The shear displacement-shear stiffness and shear displacement-shear stress relationships of prestressed GFRP anchor rods under the action of shear load were found to conform to the exponential distribution and Weibull distribution, respectively. The mechanical models proposed in this paper for shear displacement-shear stiffness and shear displacement-shear stress could effectively predict the mechanical behavior of shear damage on the joint surface of prestressed GFRP anchor rods.

In subgrade engineering, silty clay often deforms and fails due to poor strength and water stability. This study investigates the compaction and shear properties of high-moisture-content silty clay modified by quicklime. Through compaction tests and direct shear tests, the effects of different lime admixture levels and curing conditions on the compaction and shear properties of the modified soil were analyzed. The results show that the maximum dry density of the modified soil decreases linearly with the lime admixture, while the optimal moisture content increases quadratically with the lime admixture. Excessive lime admixture cannot effectively improve the optimal moisture content of the modified soil, the compaction performance of the modified soil is optimal when the lime admixture is 7 %. The incorporation of lime significantly improves the cohesion and internal friction angle of the soil. Cohesion increases with the lime admixture, while the relationship between the internal friction angle and lime admixture is not significant. Curing conditions have a significant impact on the mechanical properties of the modified soil. Under low lime admixture, immersion curing conditions significantly deteriorate the shear strength of the modified soil, while under high lime admixture (7 %, 9 %), the modified soil exhibits good water stability. Moreover, the modified soil exhibits better shear strength and water stability under higher vertical stress. The research findings reveal the mechanical and deformation characteristics of lime-modified silty clay and provide important guidance for its practical engineering application.