Modified Based On The Hoek-Brown Criterion For Releasable Strain Energy

Hoek Brown strength criterion is one of the most widely used strength criteria in geotechnical engineering.Based on the fact that energy conversion is the essential attribute of physical process,this paper modifies the H-B strength criterion from the perspective of releasable strain energy and establishes the modified 3D XH-B criterion.The research results enrich the H-B strength criterion and provide a theoretical basis for geotechnical engineering design and stability analysis.The main research achievements are as follows:(1)Based on the fact that any material and physical process should satisfy the law of conservation of energy,and the release of releasable strain energy is the internal mechanism of rock failure,it is clarified that Poisson's ratio plays an important role in the process of rock failure.(2)From the point of view of releasable strain energy,it is clarified that the existing H-B criterion is not only the empirical strength criterion,but also the energy type strength criterion expressed by releasable elastic strain energy(U^e).It is also revealed that the existing H-B criterion holds that the failure of rock will occur only when the stored releasable elastic strain energy reaches a certain critical value under any stress state and the Poisson's ratiovis equal to 0.5,which may also improve the calculation accuracy of H-B criterion key.(3)Based on the fact that the releasable strain energy is the intrinsic mechanism of rock failure,it is proposed that when the releasable elastic strain energy stored in rock reaches a certain critical value under any stress state,rock failure will occur.Therefore,based on the initial H-B strength criterion,X.Pan 3D H-B strength criterion and Zhang Zhu 3D H-B strength criterion,the existing strength criterion is modified from the perspective of releasable strain energy,and the modified 3D HH-B criterion,the modified 3D PH-B criterion and the modified 3D ZH-B criterion are established respectively.(4)The theoretical analysis shows that the modified 3D ZH-B criterion is a set of strength criteria with deformation parametersv_hb as parameters,and when the deformation parameterv_hb is equal to 0.5,it degenerates into the existing H-B strength criterion;and the determination method of the parameters of the modified 3D ZH-B criterion is consistent with that of the original H-B criterion,so the results of the former H-B criterion can be directly used,which is convenient for the popularization and application of the modified 3D ZH-B criterion.(5)The true triaxial test data of four kinds of rocks show that,compared with the H-B criterion before correction,the maximum reduction of the average error of the modified 3D HH-B criterion is 70.64%;the maximum reduction of the root mean square error of the modified 3D PH-B criterion is 36.22%;the average prediction error of the modified 3D ZH-B criterion is as low as 3.56%,and the modified 3D XH-B criterion can better describe the failure characteristics of rocks.(6)The parameter analysis of the revised 3D XH-B criterion shows that the deformation parameters v_hb decrease with the increase of rock parameters m_i in the range of rock parametersm_i,and the deformation parameters v_hb of different revised 3D XH-B criteria reflecting rock failure may be inconsistent.