Technic Study On Enhancing The Explosion Resisting Capacity Of Underground Opening Reinforced By Rockbolts

In modern warfare,with the development of science and technology,the normal penetrating underground weapons are developed quickly towards high precision, penetrating more deepness,especially,electronics technology is more and more proficient,so many protective projects will been attacked directly.Therefore,it is of great realistic and strategic significance to carry out the technic study on enhancing the anti-detonating capacity of the surrounding rock of protective projects when these underground openings reinforced by rockbolts are explosively penetrated.This dissertation will make use of the research methods of model experiments of geomechanics,numerical simulation and theoretical analysis to study the technology of enhancing anti-detonating capacity of underground opening reinforced by rockbolts and related mechanics.The main achievements are as follows:(1) According to the requirements of geotechnical engineering anti-explosion reinforcement model test,the excellent performance model test apparatus for anti-explosion structures in rock and soil engineering is designed.Based on similarity principle of model experiment techniques,considering the practical application and main assumptions,firstly,proportional coefficients are selected properly,then, simulative ratios of the materials are calculated,and lastly simulative materials are determined.At the same time,the process of model confectioning and measuring and testing techniques are represented.These conditions ensure model tests successfully.(2) Through anti-explosion reinforcement model test,the effects of density, lengh and long-short forms of rockbolts on anti-detonating capacity were explored. Some conclusions are drawn from the model test results.The anchor density can prevent crack extension,only when anchor spacing is to a certain density,it just prevents cracks from extending into the reinforced region,but the augmentation of anchor length has no control effects to prevent crack extension in wall rock.Local and dense lengthening anchors in underground opening spandrel can prevent or interdict cracks from extending in wall rock and reduce cracks.These researches have enlightened effects on enhancing anti-detonating capacity of underground openings reinforced by rockbolts. (3)Based on anti-explosion reinforcement model test,the wave curves of vertical stress,the relative roof-to-floor displacement,surface strain of underground opening wall and accelerations of roof-to-floor and sidewall were obtained. According to peak value of the wave curves,the relationship between vertical stress, the relative roof-to-floor displacement,surface strain of underground opening wall and accelerations of roof-to-floor and sidewall and scale distance were fit,which provides basis for design and construction.(4)By comparing to the anti-detonating capacity of the underground opening which is reinforced by common dense rockbolts,the anti-detonating capacities of two kinds of supernormal rockbolts supporting were firstly studied completely.The results show that the relative roof-to-floor displacement of two the underground opening which is reinforced by supernormal rockbolts supporting can be reduced significantly,and the their surrounding rocks are damaged lightly,which shows the two underground openings can enhance the anti-detonating capacity.(5) Based on the size of model test and parameters of model materials, considering partial axial strain temporal curves of the test on vault,hance and rib, dynamic response and reinforcement mechanics of rockbolts was studied with numerical analysis,and the axial stress distribution of rock bolts was obtained.At the same time,the effects of elastic module and thickness of the dense part and weakened part on the anti-detonating capacity were studied.The study indicates that firstly, displacement of underground openings arch vault decreases with the increasing of elastic module of the dense part,and displacement of underground openings arch vault is reduced significantly with the decreasing of elastic module of the weakened part,secondly,with the increasing of thickness of the dense part and weakened part, displacement of underground openings arch vault does not decrease significantly, especially the weakened part.It is a scientific guide to enhance the anti-detonating capacity of the underground opening.(6)The wave function expansion method was used to analyzes scattering on the interaction of explosive stress waves and the underground opening,and elicited the influences of such factors as an angle of incidence,the frequency of incident explosive stress wave and the radius of the underground opening,which points the way of reinforcing the underground opening effectively.