THE USE OF STOCHASTIC SIMULATION METHOD LATIN HYPERCUBE SAMPLING IN THE STUDY OF THE RESPONSE OF SOIL EXPOSED TO DYNAMIC LOAD

The paper deals with the dynamic load response in rock mass using both the methods of mathematical modeling and stochastic simulation methods. This dynamic response of rock mass is dependent both on the properties of the rock mass and on the parameters of dynamic loading. In the deterministic numerical modeling approach each input parameter is characterized by one more or less representative value only. But the reliability and predicative ability of the modeling results are governed by the reliability of input values. Stochastic simulation methods take into account the stochastic nature of the input parameters, the input characteristics and associated response of the model (modeling results) can be considered as a random variable with some probability distribution. The paper presents the results of the stochastic modeling of dynamic impact in the rock mass based on the application of Latin Hypercube Sampling (LHS) simulation method. The mentioned stochastic simulation method is applied both on the deformation and strength characteristics of the rock environment. Stochastic simulation LHS method is much more efficient in numerical modeling in comparison with widely used Monte Carlo simulation method, because it allows reducing the number of required repeated parametric calculations while maintaining the required accuracy. In the presented model the vibration source corresponds to the impact of the reverse vibratory plate type VDR22. On the basis of the mathematical modelling results the velocity amplitude of vibration response in the rock mass corresponding to the different distances from the source are then evaluated. The modeling is performed by application of Plaxis dynamic module and for the generation of random values of stochastic elastic modulus, cohesion and friction angle there was used software GLHS. This software was developed on the Department of Geotechnics and Underground Engineering of the Faculty of Civil Engineering, VSB-TU of Ostrava, for the data generation based on LHS simulation method. For each input parameters there were generated 20 input values, obtained calculating amplitudes of velocities were statistically analyzed in each distance (there were evaluated the basic statistical characteristics). On the basis of this stochastic analysis the attenuation curve of the vibration velocity with the certain level of probability were determined. Obtained attenuation curves can be used in geotechnical practice for predicting the values of vibration velocity of analogous geological environment with the identical parameters of dynamic load.