Research On Rayleigh Wave Dispersion Curve Inversion Based On Improved Sparrow Search Algorithm

Rayleigh wave exploration has been widely used in urban underground space exploration and other fields due to its advantages of high shallow resolution and strong antiinterference ability.The Rayleigh wave dispersion curve contains rich information of underground media.The shear wave velocity information of underground media can be obtained by inversion of Rayleigh wave dispersion curve.The dispersion curve inversion methods include local linearization inversion and nonlinear inversion.Nonlinear global optimization inversion has been widely studied and valued by a large number of scholars in recent years because it does not rely too much on the initial model and has strong global search ability.The sparrow search algorithm is a novel global optimization inversion algorithm with strong optimization ability and fast convergence speed.In this paper,aiming at the problem that the sparrow search algorithm has reduced population diversity and is easy to fall into local optimum in the later stage of search,combined with the characteristics of dispersion curve inversion,the sparrow search algorithm is improved accordingly.In the sparrow search algorithm,Sin chaotic mapping,dynamic adaptive weight,Levy flight,random regression boundary processing and other strategies are introduced.The improved sparrow search algorithm has stronger global search ability,and improves the convergence speed and solution accuracy of inversion in dispersion curve inversion.The typical geological models of increasing velocity,low velocity and high velocity are established.The improved sparrow search algorithm is used to invert the fundamental and multi-order,noise-free and noisecontaining dispersion curves.The inversion results show that the improved sparrow search algorithm can effectively and stably invert the Rayleigh wave dispersion curve.The vertical and horizontal comparison analysis with sparrow search algorithm,particle swarm optimization algorithm and sine cosine optimization algorithm shows that the inversion accuracy and stability of the improved sparrow search algorithm are significantly improved.Furthermore,the inversion test is carried out by using the internationally used surface wave inversion benchmark data set,which verifies the effectiveness and applicability of the improved sparrow search algorithm.Finally,the inversion of typical surface wave exploration example data in Wyoming Russia area of the United States is carried out,and the practicability of the improved sparrow search algorithm is tested.