.png){kind=icon}
.png){kind=icon}
Return
Study on shear behavior of the free segment in jointed rock masses anchored by full-scale NPR bolts
.png){kind=icon}
PRE
AI
J
Q
W
C
Z
K
DOI：10.1007/s10064-026-05192-8.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Negative Poisson’s ratio (NPR) bolts combine high strength, high ductility, and substantial energy-absorption capacity, making them promising for stabilizing jointed rock masses. However, the shear behavior and failure mechanism of the free segment of full-scale NPR bolts remain insufficiently understood. This study conducted full-scale double-shear tests on NPR bolts embedded in rock-like specimens with uniaxial compressive strengths of 20, 35, and 50 MPa, representing soft, medium-hard, and hard rock, respectively, under three prestress levels. Conventional MSGLD-335 positive Poisson’s ratio (PR) bolts tested in 35 MPa specimens served as controls. The results show that free-segment failure is governed by combined tensile and shear action, and the dominant failure mode changes from tension-dominated to shear-dominated as host-rock strength increases. A deformation model demonstrates that host-rock strength controls the extent of the shear-deformation and shear-reaction zones and the distribution of plastic deformation, thereby determining the failure mode. Under the same host-rock strength, the peak shear force, rupture displacement, and energy absorption capacity of NPR bolts were 1.37, 1.86, and 2.76 times those of PR bolts, respectively. A relative necking index was proposed to quantify deformation compatibility and material utilization; its lower mean value for NPR bolts indicates more uniform plastic mobilization. These findings clarify the free-segment shear mechanism of full-scale NPR bolts and provide a basis for the design of bolting systems in jointed rock masses.
Keywords:
NPR bolt
anchored jointed rock
host rock
shear test
free segment
Journal
IF:
4.2
Papers:
5.1K
Citations:
1.6W
Organization
Cited Papers