The Research On The Application Effect Of Two Geophysical Methods In Karsts Collapse

Pavement collapse is a kind of geological disasters,and geological hazards are badly harmful to the construction of the project and the safety of the people's property.We need to take it seriously.Karsts collapse is the main cause of the collapse of Southwest China,and this paper introduces the definition and main cause of karsts collapse.It is clear that the main reason for the collapse is that the karsts fissure provides the space foundation for the formation of the Quaternary overburden soil caves.Void area exploration of soil hole is one of the most direct means of collapse.This paper study what based on the geological survey,hydrodynamic conditions and geophysical features.Surface wave method and GPR are used to study the location and type of the fracture zone,the location and the size of the erosion zone.Influences of main geological parameters of GPR exploration are conductivity,permittivity and permeability,and the main geological parameters affecting the surface wave exploration are the shear wave velocity.This paper tries to carry through exploration of the road collapse two aspects of geological electromagnetic properties and elastic wave properties.First of all,the feasibility study is carried out from the basic principles and technical aspects of the two geophysical methods,combined with a large number of literatures,and then working equipment,equipment parameters and observation system of two geophysical methods are clear combined with the geological and geophysical characteristics.Secondly,the FTDT software is used to simulate the radar imaging.By comparing the simulation results with the actual exploration data,more efficient and rapid positioning of abnormal size,location,improve the accuracy of the final data interpretation.In the data processing phase,it is clear that the higher mode surface wave is more sensitive to the thickness of the deep layer than the fundamental wave.The phase velocity curve extracted by FFT is the result of the interaction of multi modes surface waves.Thenthe genetic algorithm is used to analyze the joint inversion of multimode surface waves.It can reduce the multiple solutions and improve the precision of inversion.Combined with the above researches,we used the Rayleigh wave exploration in the ballastless track and used comprehensive exploration of Rayleigh wave and GPR in the filling embankment.Based on the analysis of geological profile and drilling data,the application of the surface wave method to the exploration of karsts fractured zone of bedrock is good.The synthesis of the GPR and the Rayleigh wave method not only has a good effect on the bedrock karsts,but also has a good effect on the exploration of the middle layer of the Quaternary Cover.Therefore,the exploration of the soil cave and karsts cavity can be more accurate to evaluate the collapse risk of the karsts area,and make an effective contribution to the protection of the construction of the project and the safety of the people's property.