Research And Application Of Rock Mass Quality Classification Method Based On Statistical Mechanics Of Rock Mass

The existing rock mass classification or classification methods are all based on the stability of the surrounding rock,with the goal of excavation and support design,that is,according to various geological conditions and rock physical and mechanical characteristics that affect the quality and stability of the rock mass,the tunnel surrounding rock It is divided into several grades with different quality and stability as the basis for evaluating the stability of rock mass.However,in the existing surrounding rock classification,the rock-soil characteristics and structural planes of various levels of surrounding rock have been described accordingly,but for the different structural plane parameters exposed by excavation and their influence,the various surrounding rock exhibits There is no further quantification method for the anisotropy and deformation and failure characteristics,which results in the difference between the deformation and failure of the surrounding rock and the prediction and evaluation results,and it is difficult to adjust the quality of the surrounding rock.Therefore,based on the rock mass quality classification theory of statistical rock mass mechanics,combined with numerical simulation analysis,this paper has developed different rock mass quality classification procedures and the influence of rock mass parameters on quality classification.Based on the Shuangshui Tunnel,a case analysis is carried out and corresponding support suggestions are put forward.The main research contents and results are:(1)Comparing the relationship between each classification and rock mass parameters,proposes a BQ index-based rock mass deformation modulus estimation method,which is applied to the Three Gorges The estimation of rock mass mechanical parameters in a dam site area of the project is more consistent with the field mechanical test data,which provides a reasonable quantitative approach for estimating the rock mass deformation modulus through the BQ index.(2)Based on the statistical rock mechanics theory and the previous theories,a method of surrounding rock classification suitable for tunnel construction is proposed.The calculation program of RMR classification method,BQ classification method,Q system classification method,Z system classification method and SMRM(Statistical mechanics of rock Mass)rock mass classification method was compiled using C#language,showing the all-round quality level of rock mass and anisotropic characteristics,based on the test data of the rock mass bearing plate of a hydropower station,verified the accuracy of the quality classification calculation method,and discussed the influence of rock mass structural plane parameters based on statistical rock mass mechanics on the rock mass quality score law.(3)Based on the Liangshui tunnel project of the Lanyu Railway,apply the statistical rock mass mechanical quality classification program to the project,and based on FLAC^3Das the technical platform,apply the statistical rock mass mechanical quality classification constitutive model to the Lanyu Railway The Liangshui Tunnel is numerically simulated and compared and analyzed with the field measured data.The classification method is modified according to the anisotropic structure of the surrounding rock on site to meet the engineering needs of the tunnel at different construction stages.(4)Based on the quality grading program developed,the RMR,BQ and SMRM quality grading of rock mass was carried out with a tunnel of Lanzhou-Chongqing Railway as an example to verify the applicability and accuracy of the grading calculation program and the practicability of the program.Meanwhile,the results of different grading methods were compared according to the above results.