Experimental Study On Load And Displacement Of Prefabricated Anchorage Structure In Deep Semicircle Arch Roadway

Deformation and failure of surrounding rock of deep roadway are not only related to ground stress and strength of surrounding rock,but also to bearing structure of surrounding rock support and reinforcement.The failure of surrounding rock is not equal to the overall instability of roadway,so it is more pertinent to study from the angle of instability of bearing structure of surrounding rock of roadway.The instability of surrounding rock bearing structure can not be separated from its stress state.To study the structural instability,the first thing is to study the relationship between the load and displacement.In order to obtain the relationship between the instability of anchorage structure and its load and further reveal the mechanism of the interaction between anchor and surrounding rock forming the bearing body of anchorage structure,this paper combines the key project of National Natural Science Foundation of China"Basic Theory Research on Information Control of Deep Mining and Roadway Surrounding Rock Stability"?51734009?and the sub-project of National Key Research and Development Program?2017YFC0603001?"Thousand-meter Deep Well"The law of surrounding rock deterioration and strength attenuation of roadway under strong mining is studied in the West Wing track roadway at-967m level in Kouzidong Coal Mine of China Coal Xinji Energy Source.By means of physical simulation test,theoretical analysis and numerical simulation,the bearing capacity and displacement relationship of pre-fabricated semi-circular arch anchorage structure and the bearing arch structure effect formed by pre-tightening force of bolt under different parameters of bolt support are studied comprehensively.A systematic study should be carried out.The main research contents and conclusions are as follows:?1?According to the post-peak deformation conditions of surrounding rocks in deep roadways,different proportions of river sand,cement and gypsum are developed to meet the requirements of similar physical simulation tests;prefabricated anchorage structure moulds are developed independently,and model tests of bearing bodies of prefabricated anchorage structures in deep roadways under different anchor density conditions are carried out.For the first time,the loads of three different anchorage structures in the whole process are obtained.Load-displacement curves are presented,and the criterion of expressing the bearing capacity of anchored structures by"average load variation of relative closeness of roof and floor"is proposed.The evolution laws of radial and tangential stresses on the surface of the bearing body of anchored structures are analyzed.The evolution rules of displacement field during the failure process of the bearing body of anchored structures are revealed by using PhotoInfor V7.2 digital photogrammetry analysis system of the evolution law.?2?Based on the experimental results of the three precast anchorage structures mentioned above,the factors affecting the strength and thickness of the bearing body of the anchorage structure are analyzed based on the Mohr-Coulomb yield criterion,and the influences of the radius of the roadway,the parameters of the bolt,the material of the bolt,the cohesion of the surrounding rock and the angle of internal friction on the strength and thickness of the bearing body of the anchorage structure are studied.The ultimate failure mode and mechanism of the bearing body of anchorage structure under different anchor density conditions are obtained.?3?Based on the whole process of load-displacement test of prefabricated different anchorage structures,FLAC^3D numerical model is established and the load-bearing characteristics of anchorage structures are studied.The influence of parameters such as pre-tightening force,diameter,density and length of anchor bolts on the strength and scope of diffusion stress field is systematically analyzed.The forming mechanism of load-bearing capacity of anchorage structures is revealed,and the load-bearing arches with different parameters of anchor bolts are obtained.The variation of strength and thickness of the structure.?4?According to the research conclusion,the in-situ stress and the thickness of loosening zone were measured in west-wing track roadway of-967m level in Kouzidong Coal Mine,and the support parameters were optimized.The stability control concept of"yielding+grouting+active and passive coordinated support"was put forward.The new scheme not only makes the anchorage structure play an integral anchorage role,but also enhances the strength and thickness of the anchorage structure.The field industrial test has achieved good support effect.