The Dynamic Characteristics Study On The Laterite Of The Kunming Changshui International Airport Of Underground Structure

With the further implementation of China’s western development strategy,the construction of infrastructure in western China,especially in Yunnan Province,has advanced by leaps and bounds,such as the construction of highways,highways,high-speed rails,airports,etc.At the same time,the high-efficiency development and utilization of underground space has gradually been paid great attention.Yunnan Province is in a high-intensity earthquake zone,with the continuous development of engineering construction and the continuous development of underground space,geological disasters affected by earthquakes are becoming more and more serious.Various types of the Laterite are widely distributed in Southwest China,which is not only an important land resource,but also an extremely important foundation for engineering construction.However,since modern times,due to continuous changes in global climate conditions,the Laterite continued to crack under the action of the Laterite.The structural unit body is granulated to form loose Laterite,which leads to the continuous deterioration of the engineering properties of the Laterite.In addition,current international and domestic experts and scholars’ research on the dynamic characteristics of soils under dynamic loads mainly focuses on loess,soft clay and sand.There are not many studies on the dynamic characteristics of the Laterite and the earthquake resistance of underground structures.And so far,few studies on the classification dynamics of the Laterite have been retrieved.In general,the research on the Laterite at home and abroad lacks systematicity,the theoretical issues are ambiguous,and the research object is unclear.Therefore,it is very urgent and necessary to accelerate the research on the dynamic characteristics of the Laterite and the underground seismic research.This has a positive significance for the seismic stability design of the Laterite distribution area.This article is based on the research on the engineering properties of residual Laterite in mudstone of Kunming Changshui International Airport,It focuses on the study of its dynamic characteristics and earthquake resistance of underground structures,the main research contents are as follows:(1)Perform dynamic deformation tests on residual Laterite in mudstone to explore its dynamic deformation characteristics under cyclic loading,it mainly analyze the influence of consolidation confining pressure and consolidation on the dynamic deformation characteristicsof residual Laterite in mudstone.And geting the relationship curve between dynamic stress,dynamic modulus,damping ratio and dynamic strain.Through data processing,we know that the dynamic strain increases with the increase of dynamic stress,the dynamic modulus increases with the increase of consolidation pressure and consolidation ratio,the damping ratio decreases with the increase of consolidation confining pressure and increases with the increase of consolidation ratio.(2)Perform dynamic strength tests on residual Laterite in mudstone to explore its dynamic strength characteristics under cyclic loading,it mainly analyze the influence of consolidation confining pressure and consolidation on the dynamic strength characteristics of residual Laterite in mudstone and the change of dynamic shear strength index under the above factors.Through data processing,we know that if the number of failure cycles is the same,as the consolidation ratio increases,the dynamic stress decreases.If the consolidation ratio is the same,the number of vibrations when reaching the failure state increases with the increase of dynamic stress.As the consolidation ratio increases,the dynamic failure strength gradually decreases,and as the confining confining pressure continues to increase,the dynamic failure strength increases instead.Comparing the results of static and dynamic triaxial experiments,it is found that the static internal cohesion of residual Laterite in mudstone of Kunming Changshui International Airport is greater than the dynamic internal cohesion,and the angle of internal friction measured by the static triavial is smaller than that of the dynamictriavial.(3)Using MIDAS GTS finite element software for numerical simulation.Set embedding depth to variable and using the response acceleration method,a one-dimensional model was used to simulate the deformation of the underground structure of the Laterite layer under twice Kobe wave vibration.Through the time-history analysis method,a two-dimensional model is used to simulate the deformation of the underground structure of the Laterite layer in the EL-Centro wave at different embedding depths.The basic law and influence degree of acceleration stress and strain response of one-dimensional model and two-dimensional model of soil-underground structure under different burial depths under the action of ground motion are preliminary studied.(4)Using MIDAS GTS finite element software,a 2D soil-underground structure system with a depth of 6m,10 m,and 16 m was established.The soil in the site conditions is a single residual Laterite in mudstone.The seismic response of the underground structure under theaction of earthquake is studied,and the part of the underground structure that has the largest response when damaged by earthquake is analyzed.