Research On Extension And Modeling Method Of Statistical Mechanics Of Rock Masses Constitutive Model Based On FLAC^3D

The mechanical calculation of engineering behavior of fractured rock mass has always been a difficult problem in the research of rock mass mechanics and analysis of rock mass engineering.The spatial variation of mechanical parameters and rock mass quality of random structure rock mass in complex stress field and the calculation of anisotropic mechanical behavior are the basic difficulties faced by traditional geotechnical mechanics analysis,and also the main source of analysis deviation of existing mechanical tools.Based on statistical mechanics of rock masses,the constitutive model(Joint Model.dll)of anisotropic fractured rock mass is developed by C++programming,the expansion module can realize the spatial point cloud distribution calculation of rock mass deformation modulus,SMRM quality classification,stability coefficient,failure probability,failure stress margin(rock-burst index),reinforce requirement and other indicators.In addition,the high-precision modeling of rock surface is also one of the error sources of numerical simulation technology.In this paper,combined with the 3D space point cloud modeling method,the geological body can be described quickly and accurately.The point cloud modeling model is applied to the stability evaluation and engineering parameter calculation of a mine slope in Zhejiang Province by combining the geometric and mechanical parameters of rock and discontinuity.The joint model and expansion calculation module are applied to a tunnel in Northwest China,and the calculation results are consistent with the monitoring results.The main research contents and conclusions are as follows:Firstly,based on UAV photographing technology,the working steps of UAV field photographing are summarized,and the 3D geological surface model is reconstructed by using SFM-MVS algorithm to obtain the surface information of a dangerous rock mass on a highway slope in Zhejiang Province,and the surface model is processed by down sampling,de-noising filtering,simplification and smoothing,then the data file is imported into rhinoceros software,and the 3D model and mesh are constructed after the mesh is generated into surface by Rhino-Resurf command.Finally,the model is triangulated by griddle plug-in and saved in FLAC^3D recognizable*.f3grid format.The method is applied to the stability analysis of a slope isolated rock mass in Zhejiang Province.The results show that the stress and displacement increase and tend to be stable with the increase of the formation depth,which is consistent with the actual formation distribution,which proves the reliability of the method.Secondly,on the platform of numerical simulation software FLAC^3D,the SMRM constitutive model and engineering parameter expansion module are written into C++header file and source file,and compiled into dynamic link library file which can be automatically called by FLAC^3D.The secondary development environment and development steps of FLAC^3D are introduced.Taking sun Xushu's indoor experimental data and Wang Jie's calculation results of rock mass damage constitutive model considering dip angle as examples,the variation trend of fractured rock mass strength under different confining pressure conditions is compared.The stress-strain relationship of the Joint Model constitutive model under elastic condition is verified by using Liu Zhe physical finite element model experiment of China University of mining and technology.Finally,3D geological modeling method,Joint Model constitutive model and extended calculation module are applied to Nanmen xinxing and Mayuan mines.Using phantom 4 RTK UAV on site obtains the point cloud data for 3D geological modeling.Combined with the geological conditions and given the Joint Model constitutive model,the calculation shows that the maximum displacement of 3.15cm and the maximum failure probability of 43%are near the fish fin shape at the junction of the two mines.The deformation modulus of the area is 1GPa,and the rock mass quality classification RMR(SMRMz)is 15?30,BQ is 172.2?263.6,which is about the rock mass quality of grade V?IV,and the calculation results are consistent with the on-site investigation results;through the analysis of the stability of the rock mass in this area by the flat projection map,it shows that the rock mass in Nanmenxinxing mine is easy to be destroyed along the strata under the condition of mutual cutting of fractures;the rock mass of Mayuan mine is easy to wedge failure under the mutual cutting of fissures,and this area is a high risk area of geological disasters.In addition,the user-defined constitutive model Joint Model and the expansion calculation module are applied to the Liangshui tunnel of Lanzhou-Chongqing railway.The calculation results show that the overall stability of the surrounding rock at the left spandrel and the right arch bottom of the tunnel section in the experimental section is poor,the anisotropy of the whole section is significant,and the failure probability at the left spandrel and the right arch bottom of the section reaches 100%,and the stability coefficient is less than 1.0,the rock mass quality classification RMR(SMRMz)is 15,BQ is 172.2,which is about grade v.