The Determination Method Of Mechanical Parameters In Disturbed Zone Based On Acoustic Test And Its Application

The excavation disturbance area will be formed due to the excavation unloading disturbance of slope and tunnel engineering.Rock mass mechanical parameters in excavation disturbance area are important factors affecting slope and tunnel deformation and stability.At present,there are many studies on determining the scope of excavation disturbance region,but the research on the spatial variation law of mechanical parameters in the disturbance region is rare.Therefore,in this paper,the spatial variation rules of mechanical parameters in the disturbance region are studied by combining Hoek-Brown criterion and acoustic testing,and a method to determine the mechanical parameters in the disturbance region is proposed,which is applied in engineering cases.The main research contents and results of this paper are as follows:?1?Based on the theory of elastic-plastic mechanics,the calculation method of plastic circle radius based on M-C criterion and H-B criterion is introduced.The influences of geological intensity index?GSI?and disturbance coefficient?D?on the plastic circle radius of H-B criterion parameters are analyzed.?2?The H-B criterion parameters GSI and D are derived quantitatively,and the relationship between GSI and D and rock mass compressional wave velocity(1is established.The calculated value of the formula is close to the actual value,so the more accurate mechanical parameters of rock mass can be obtained by using wave velocity of rock mass.?3?Through the statistical analysis of the acoustic test data collected in different engineering cases,the variation rule of wave velocity in the excavation disturbance area with depth is obtained.The function applicable to the variation rule of wave velocity in the disturbance area is determined by fitting the data with different functions.Combining this function with H-B criterion,a method for determining the spatial variation of rock mass mechanical parameters in excavation disturbance area based on acoustic wave test is proposed.?4?Based on a acoustic testing data of slope engineering,based on the proposed methods to analyze the disturbance zone H-B standard parameters and space changing rule of rock mass mechanics parameters and their weakening,get disturbed zone mechanical parameters is minimized is the internal friction Angle,followed by the cohesive force,deformation modulus,tensile strength,compressive strength weakening degree;Finally,the influence of different values of GSI and D on the variation law of mechanical parameters and the slope stability is compared and analyzed.The study shows that whether to consider the excavation disturbance area and the accuracy of mechanical parameters have obvious influence on the analysis results.?5?The numerical model of the tunnel was established by using FLAC software,and the variation rules of deformation and plastic zone of the tunnel under the condition of EDZ were compared and analyzed.By comparing the monitoring data,the correctness of the method to determine the mechanical parameters in the disturbance region is verified.