Fracture properties of jointed rock infilled with mortar under uniaxial compression

Grouting is commonly used to fill rock joints to provide reinforcement in geotechnical engineering. Understanding the fracture behavior of grouted rock joints depends on the characterization of infilled rock joints. In this work, mortar-filled rocks with grooved granite joints an inclination of 45 degrees and infilling mortar layer between granite joints were simulated and a preexisting cracks were assumed in mortar layers. Uniaxial compressive tests were performed on 20 specimens with different initial crack lengths a. Mix mode I-II fracture occurred in joints due to compression-shear condition. Peak load P-max and fracture energy G(0) were determined based on experimental load-deformation curves. The obtained results showed that both peak load P-max and specific volume fracture energy G(f-V) were observed to decrease with increasing initial crack length a. A simple bilinear distribution of local volume fracture energy g(f-V) was assumed to evaluate the effect of front boundary on specific volume fracture energy G(f-V) to obtain the sizeindependent real fracture parameter of mortar-filled rock joints G(F-V). Experimental results were also obtained by the established front boundary effect. It was observed that volume fracture energy and front boundary zone length were G(F-V) = 1.7 N/mm(2) a* = 17.5 mm, respectively, which were consistent with experimental observations.