Numerical Analysis of Mechanical Characteristics of Constant-Resistance, Energy-Absorbing and Anti-Scour Bolts

Abstract

In order to improve the impact resistance mechanical properties of bolt, the requirements of rock burst roadway support must be met. Based on the requirements that the anchor should have a reasonable deformation load threshold, high stroke efficiency, constant reaction force and stable repeatable deformation damage mode. A constant resistance anti-impact device was designed, and a new constant resistance energy-absorbing impact anchor rod was designed in combination with a conventional anchor rod, and the working principle of a constant resistance energy-absorbing impact anchor rod was given. ABAQUS finite element software was used to analyze the mechanical properties of bolt and the results showed that the constant resistance energy-absorbing anti-shock anchor has a stable and repeatable deformation damage mode under both static and impact loads, and the three indexes of the constant resistance energy-absorbing anti-shock anchor, such as yield distance, impact resistance time and energy absorption, are significantly better than those of the conventional anchor. The impact energy and impact velocity have less influence on the load-bearing capacity and stroke efficiency of the impact device. The impact velocity has less influence on the indices of the rod yield load, breaking load, absorbed energy and the yield distance of a conventional anchor and constant resistance energy-absorbing anti-stroke anchor, and the impact resistance time decreases non-linearly with the increase in the impact velocity.

Effects of deflection angle on the mechanical properties of constant-resistance, energy-absorbing, and anti-scouring bolts

“…Principles of application of constantresistance, energy-absorbing, and antiscouring bolts in the presence of a deflection angle Bolts have a much larger dimension in the lengthwise direction than the other two directions, providing mainly tensile and shear resistance, with very little bending and compression resistance (Wu 2009). Based on the theory of yielding scour protection support and the principles of ideal energy-absorbing device design (Pan et al, 2014a;Pan et al, 2014b;Tang et al, 2022), it is proposed that constant-resistance, energy-absorbing, and anti-scouring bolts in the presence of deflection angles should have the following basic characteristics: 1) Reasonable deformation load threshold. The load carrying capacity of the anti-puncher in the force- Frontiers in Earth Science frontiersin.org displacement curve of the anchor rod is the deformation load threshold of the anchor rod, which is set at 90-110% of the yielding force of the rod to ensure that the anti-punching device is playing a role near the yielding stage of the rod.…”

“…3) The force-displacement curve of a constant-resistance, energyabsorbing, and anti-scouring bolt consists of five parts: "linear elastic stage", "expansion stage", "yielding stage", "strengthening stage", and "breaking stage" (Tang et al, 2022). The change in position of the expansion stage reflects the strength between load-bearing properties of the antipunching device and bolt.…”

Experimental Study on Mechanical Properties of Automatic Anchoring Preloaded Energy Absorbing Anchor Rods

“…The right outer surface of the energy absorbing anchor rod is provided with an external thread, the nut is screwed to the right end of the rod through the external thread, and the anchorage force warning stopper is fixed on the axial right end of the nut. The pre-tightening force warning washer, the energy-absorbing casing bulging block, the constant resistance energy absorber [21], and the tray are set on the rod body in order, as shown in Figure 2. The constant resistance energy absorber is a thin-walled round tube structure, the right end of the constant resistance energy absorber has a flared mouth structure, the constant resistance energy absorber is coated with reflective paint, and the bearing capacity of the constant resistance energy absorber is designed to be 95-100% of the yield force of the rod.…”

“…Th compresses the pallet to apply pre-stress to the anchor rod, the deformation of th rounding rock is transferred to the rod body through the pallet and nut, the workin sistance of the rod body increases to control the deformation of the surrounding rock the energy-absorbing casing bulging block plays the role of adjusting the energy-ab ing resistance after expanding and deforming. The right outer surface of the energy absorbing anchor rod is provided with a ternal thread, the nut is screwed to the right end of the rod through the external th and the anchorage force warning stopper is fixed on the axial right end of the nu pre-tightening force warning washer, the energy-absorbing casing bulging block, the stant resistance energy absorber [21], and the tray are set on the rod body in ord shown in Figure 2. The constant resistance energy absorber is a thin-walled round structure, the right end of the constant resistance energy absorber has a flared m structure, the constant resistance energy absorber is coated with reflective paint, an bearing capacity of the constant resistance energy absorber is designed to be 95-10 the yield force of the rod.…”

Design of Pressure Energy-Absorbing FRP Anchors and Numerical Analysis of Mechanical Properties

“…Entering 1000-2000 m deep mining, coal mine impact ground pressure and other dynamic disasters are more significant [25][26][27][28]. In recent years, practice has proved that the use of energy-absorbing support can effectively control the deformation of roadway-surrounding rock and can effectively prevent and control roadway impact ground pressure [29][30][31]. However, conventional FRP anchors (hereinafter referred to as conventional anchors) have low elongation and poor impact mechanical properties due to low energy absorption, and these do not meet the requirements of impact roadway support.…”