基于分段式模型考虑界面损伤的GFRP锚杆-砂浆粘结性能数值模拟

通过编写Vumat子程序定义玻璃纤维增强塑料（GFRP）锚杆材料参数，并考虑GFRP锚杆与砂浆界面的不均匀及损伤特性进行正交各向异性建模，借助ABAQUS有限元软件对GFRP锚杆与砂浆界面的粘结滑移特性进行分段模拟，探究GFRP锚杆轴力、界面剪应力分布形态，进而对不同直径GFRP锚杆-砂浆界面力学特性进行分析。研究结果表明：分段式有限元模型能够较好地反映GFRP锚杆-砂浆的粘结特性。随着施加荷载的增加，GFRP锚杆所受轴力逐渐增大，荷载传递深度逐渐加深，锚固作用自上而下逐渐发挥；GFRP锚杆拔出所需最大拉力、界面破坏位移随直径减小而增大。GFRP锚杆发生破坏的临界直径为28 mm，当直径大于28 mm时发生滑移破坏，直径小于28 mm时发生强度破坏。计算确定直径28 mm GFRP锚杆的锚固系数K₁为0.155。

Numerical Simulation of Bonding Performance of GFRP Anchor-mortar Considering Interface Damage Based on Piecewise Model

The material parameters of glass fiber reinforced plastic (GFRP) bolt were defined by writing VUMAT subroutine. Orthotropic anisotropic modeling was carried out considering the non-uniformity and damage characteristics of the interface between GFRP bolt and mortar. The bond slip characteristics of the interface between GFRP bolt and mortar were simulated sectionally by ABAQUS. The distribution of axial force and interfacial shear stress of GFRP bolt were explored, and the interface mechanical properties of GFRP bolt-mortar with different diameters were analyzed. The results show that the piecewise finite element model can better reflect the bonding characteristics of GFRP bolt-mortar. With the increase of the applied load, the axial force of the GFRP bolt gradually increases, the load transfer depth gradually deepens. The anchoring effect gradually plays from top to bottom. The maximum pull force and interfacial failure displacement of GFRP bolt increase with the decrease of diameter. The critical diameter of slip failure and strength failure is 28 mm. The slip failure occurs when the diameter is larger than 28 mm and the strength failure occurs when the diameter is less than 28 mm. The anchorage coefficient K₁ of 28 mm diameter GFRP bolt is determined to be 0.155.