Study On Roadway Supporting Design Based On Bolt Pull-out Test

Nowadays, anchor bolting technique is widely used in the coal mine roadway supportingtechnology. Since its beginning to be applied, lots of scholars have contribution a lot of timeand energy on the supporting design research, certain achievement has also beenobtained. However, the current theoretical research in some aspects on request still can notcatch up with engineering practice. In the design process, a lot of supportparameters design value not rely on real theoretical calculation to estimate, but accordingto some weak construction experience.The design process focused on traditional experience,and some focused on the use of the formula, but these theories are too conservative, thebolt strength parameters are higher than the support structure itself requires, safe enough butnot economic. In this paper, the force of the bolt load based on the transfer model, relatedfactors on the mechanical mechanism of bolt under pull-out load. when the role andinfluence of anchoring effect were analyzed at the same time, according to thespecific engineering environment, the anchor rod field pull-out load test underthe corresponding engineering geological environment. The main contents and conclusionsare:(1) The analysis on anchorage mechanism and failure mode. Summary of how andwhy the anchor damage, analyzed in load transfer of anchorage section in the process,mechanism and mechanical behavior of adhesive force between the two interface.(2) Summarize the shear slip constitutive relation model between rock massand anchor. Based on the constitutive model of shear wall interface establishedby B.Benmokrane, and adopting the load transfer function method, to create theelastic-plastic theory model, the stress status of anchor rod body and surrounding rock body in each phase under the action of drawing load are analyzed; and the various parametersaffecting the anchoring effect for the analysis.(3) Based on the pullout load tests of anchor obtained, the strength parameters K1andshear anchor layer, the affected anchor diameter D, anchoring defect length and the locationof the stress distribution and the pull-out load on anchoring defect anchor. To make a designcombined with the existing calculation methods of bolting design for the design ofbolt support.(4) The optimization of the supporting design scheme is applied to the engineeringexample, the construction process of follow up monitoring and discovery and the originalsupporting scheme comparison, based on the supporting design scheme of roadwaybolt anchor pullout load test is rational and feasible.