Abstract
Due to the frequent occurrence of geological disasters, such as geological faults, tectonic activities, and local activities, the study of a cable structure capable of resisting large deformations and of absorbing energy is investigated. The plane length is increased step by step based on the deformation and energy absorption values of the original NPR anchor cable model. Three kinds of two-stage constant resistance bodies are designed following the three principles: first-stage friction plus second-stage expansion, primary expansion plus secondary expansion, and first-stage expansion plus second-stage friction. Moreover, a giant NPR anchor cable with extraordinary mechanical properties is developed. Via a theoretical analysis and laboratory static tensile tests on traditional NPR and giant NPR anchor cables, their force characteristics, constant resistance, and fluctuation trends are related to the size and the structure of the constant resistance body. In addition, the most remarkable improvement takes place in the cables’ deformation and energy absorption properties. The deformation increases from 1000–2000 mm to 3000–4000 mm, while the energy absorption value increases from 4.21 × 105–1.09 × 106 J to 3.2 × 106 J. The constant resistance value is also effectively enhanced to 550–723.7 kN. This provides a reliable technical support for their application in deep geological faults.
Highlights
Bolt support technologies are widely used in the field of slope reinforcement and support-based techniques, due to their abilities in improving the structural strength of the rock mass and in enhancing the slope stability [1,2,3]
Energy absorption bolts allow one to obtain around 200–300 mm deformation of the rock mass upon maintaining the upper strength of the surrounding rock [13, 14]. e tensile process with elastic deformationstrain hardening-strain softening was related to the use of energy absorption bolts with an increased working resistance upon a change in the rock deformation, and it appears that all the three anchors hardly meet the large deformation factors caused by slope instabilities and the
When the prestressed pallet and the steel strand are subjected to a tensile load, the relative movement between the cone and the sleeve transfers the load to the constant resistance body via the steel strand. is movement is equivalent to the deformation of the anchor cable. e reverse resistance generated during the movement is equal to the constant resistance
Summary
Bolt support technologies are widely used in the field of slope reinforcement and support-based techniques, due to their abilities in improving the structural strength of the rock mass and in enhancing the slope stability [1,2,3]. When the depth of an excavation increases, geological disasters, such as large deformations mostly caused by landslides, cannot be avoided by employing traditional small-deformation support systems. According to the working characteristics of three types of such anchor bolts, one can classify them as follows: strength bolts, yield bolts, and energy absorption bolts [10]. Yield bolts have a strong resistance against possible large deformations of the rock mass, despite their strength is small [12]. E tensile process with elastic deformationstrain hardening-strain softening was related to the use of energy absorption bolts with an increased working resistance upon a change in the rock deformation, and it appears that all the three anchors hardly meet the large deformation factors caused by slope instabilities and the Energy absorption bolts allow one to obtain around 200–300 mm deformation of the rock mass upon maintaining the upper strength of the surrounding rock [13, 14]. e tensile process with elastic deformationstrain hardening-strain softening was related to the use of energy absorption bolts with an increased working resistance upon a change in the rock deformation, and it appears that all the three anchors hardly meet the large deformation factors caused by slope instabilities and the
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