The Distribution of Shear Stress along the Anchoring Section of Prestressed Bolt

Zhang, Bo; Li, Shu Cai; Yang, Xue Ying; Zhang, Dun Fu; Li, Ming Tian

doi:10.4028/www.scientific.net/amm.90-93.2243

Cited by 8 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This support system could increase the sphere of pretension force, and the effect of pretension force anchor in soft rock is better than that in hard rock [40]. Cable reinforcement must be added to the support system with an overhanging effect and anchored beyond the EBZ in the stable roof rocks [4].…”

Section: Discussionmentioning

confidence: 99%

Assessment of Excavation Broken Zone around Gateways under Various Geological Conditions: A Case Study in Sichuan Province, China

Yang

Cao

et al. 2016

Minerals

View full text Add to dashboard Cite

Abstract:To study common failure characteristics of gateways, a total of 55 typical gateways at coal mines, in Sichuan Province, China, were selected for investigating the rules of broken widths based on the ground-penetrating radar (GPR) technique and numerical model. Results indicated that the broken width values around the gateways were larger than 1.5 m, and those in the roof and high side wall were larger than those in the low side wall, as a whole. The width values had close relationships with the thickness of the coal seam and immediate roof, angle of the coal seam, and depth of the gateways. Furthermore, combined with the plastic zone of numerical models in 3-Dimensional Distinct Element Code (3DEC) and the broken width, we obtained the excavation broken zone (EBZ) cross-section diagram for each gateway and determined that the EBZ appeared to have a basically elliptical shape-with the long axis along the seam inclination direction and the short axis along the vertical direction of the rock layer-and that this elliptical shape was only slightly affected by the gateway cross-section shape. It was observed that the failure extent was greater in the seam inclination direction than in the vertical direction of the rock layer. Obviously, the gateways presented asymmetric failure characteristics and implied that an asymmetric support system should be provided when using bolts, cables, and shotcrete combined with steel mesh and steel belts. Such a support system could improve material parameters and form a combined arch structure in surrounding rocks, with arch crown and arch springing thicknesses that are larger in the roof and high side wall.

show abstract

Section: Discussionmentioning

confidence: 99%

Assessment of Excavation Broken Zone around Gateways under Various Geological Conditions: A Case Study in Sichuan Province, China

Yang

Cao

et al. 2016

Minerals

View full text Add to dashboard Cite

show abstract

“…You [37,38] obtained an elastic solution of the shear force distribution of the full-length bonded bolt along its body through theoretical calculations and obtained the normal stress and shear stress distribution law along the axial direction of bolts as well as the evolution process with the increased load. Zheng [39][40][41] used MATLAB software (MathWorks Inc., Natick, MA, USA) to study the influence of the anchoring method, surrounding rock properties, bolt diameter, and pre-tightening force on the distribution of prestress in the bolt body and surrounding rock. Furthermore, the bolt-supporting parameters were optimized.…”

Section: Introductionmentioning

confidence: 99%

Full-Stress Anchoring Technology and Application of Bolts in the Coal Roadway

et al. 2021

View full text Add to dashboard Cite

The traditional anchoring method of bolts has insufficient control over the surrounding rock of the coal roadway. Based on this background, full-stress anchoring technology of bolts was proposed. Firstly, a mechanical relationship model of a bolt-drawing, anchoring interface was established to obtain the equations of the axial force and obtain shear stress distribution as well as the decreasing-load transfer law of the anchoring section of bolts. Through studying the prestress-loading experimental device of bolts, we found that increasing the initial preload could increase the axial force under the same conditions and the retarded anchoring section could control the axial-force loss of bolts in the middle of the anchoring section. Under the full-stress anchoring mode, the effect of applying a pre-tightening force was better than that of applying a pre-tightening force under traditional anchoring methods. Moreover, FLAC3D (Fast Lagrangian Analysis of Continua 3D; ITASCA (Ita sca International Inc), Minnesota, USA) numerical simulation calculation was performed. Under the full-stress anchoring mode of bolts, the increased anchoring length reduced the damage of the anchoring section, with a wider control range of the rock formation and higher strength of the compressive-stress anchoring zone. Based on the above research, four methods for applying the full-stress anchoring technology of bolts in engineering were proposed. The full-stress anchoring technology of bolts in the coal roadway has been applied in the support project of the return-air roadway at working face 3204 of the Taitou Coking Coal Mine of the Xiangning Coking Coal Group, Shanxi. The maximum moving distance of the roof and floor of the roadway was reduced from 200 to 42 mm, and the maximum moving distance on both coal sides was reduced from 330 to 86 mm. The full-stress anchoring technology of bolts was able to control the surrounding rock in the coal roadway.

show abstract

“…Lin and Wu [22] investigated the maximum axial force in bolts, employing conservative failure probability assumptions made by the finite element software. Using numerical simulations performed in Matlab, Zheng et al [23] analysed the influence of different anchoring methods, changes in surrounding rock properties, bolt properties, and pre-tightened forces on the pre-stress distributions in the bolt body and surrounding rock.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Fatigue Lifespan of Anchor Bolts with Consideration of Loading History

et al. 2021

View full text Add to dashboard Cite

Preloaded bolted connections are one of the most used approaches for anchoring steel structures and equipment. Preload is induced by a mechanical tightening of the nut with the required torque. In the case of anchor bolts embedded in a concrete base, the prescribed tightening procedure has to be followed for safe and reliable operation. The present paper addresses the problem of anchoring a new casting pedestal using the original anchor bolts. The aim was to verify the original anchoring system’s reliable and safe operation, taking into account the current condition of the bolts. The analysed anchoring bolts are subjected to cyclic (disappearing) stress during the rotation of the casting pedestal. If the interplays between the anchor bolt and the concrete foundation were damaged, production would shut down, resulting in high economic losses. For this reason, the authors used a modified nut with a lightened first thread when investigating the actual state of the anchoring and setting the required preload. The shape and dimensions of the nut were determined based on the results of numerical modelling. The experimental measurements consisted of two phases. In the first phase, the values of axial forces in the anchor bolts at the required preload were set using the designed dynamometers. The second phase was focused on the operational measurements. The methodology of measuring the axial forces and the interpretation of the results obtained, including a comprehensive view of the anchoring safety, provides relevant evidence of the functionality and effectiveness of the proposed solution. Based on the results of the operational measurement and the prescribed handling of the casting pedestal, the lifespan of the anchoring was determined to be 3650 days under the loading cycles to date.

show abstract

The Distribution of Shear Stress along the Anchoring Section of Prestressed Bolt

Cited by 8 publications

References 0 publications

Assessment of Excavation Broken Zone around Gateways under Various Geological Conditions: A Case Study in Sichuan Province, China

Assessment of Excavation Broken Zone around Gateways under Various Geological Conditions: A Case Study in Sichuan Province, China

Full-Stress Anchoring Technology and Application of Bolts in the Coal Roadway

Experimental Investigation of the Fatigue Lifespan of Anchor Bolts with Consideration of Loading History

Contact Info

Product

Resources

About