Preliminary Research On Application Of CT-based Virtual Simulation Test Technology Of Geotechnical Materials In Engineering Field

At present,the research and design of various geotechnical materials are still based on a large number of experiments.Although certain results have been achieved,they have gradually failed to meet social needs.The reason is that the traditional experimental-empirical method cannot fundamentally explain the structural composition and performance of geotechnical materials,and it has a large amount of loss in human,material and financial resources,which is not conducive to economic and environmental protection.In recent years,scholars in various disciplines have obtained a lot of valuable research results in the distribution rules.material properties,and interactions of various components of geotechnical materials.At present,the research and design of various geotechnical materials are still based on a large number of experiments.Although certain results have been achieved,they have gradually failed to meet social needs.The reason is that traditional experimental-empirical methods cannot fundamentally explain the structural composition and performance of geotechnical materials,and have a large amount of human,material,and financial resources,which is not conducive to economic and environmental protection.In recent years,scholars in various disciplines have obtained a lot of valuable research results in the distribution rules,material properties,and interactions of various components of geotechnical materials.However,at present,the research on the damage mechanism and characteristics of fiber-reinforced loess and asphalt concrete is mostly from a macro perspective,ignoring the effect of mesostructure,and the model approximation method is often used in the macro research that has been carried out,which cannot accurately reflect geotechnical engineering.Special non-uniformity of materials and randomness of destruction.Therefore,it is necessary to start from the meso-structure.Based on the particularity of the constituent materials,this paper overcomes the limitation of researching only from a macro perspective,and analyzes the special properties of geotechnical engineering materials from a micro perspective.1)Based on X-ray CT scanning experiment and MATLAB program platform,high-quality CT images of geotechnical materials are obtained through image preprocessing,so as to accurately and effectively put forward mesostructure evaluation indicators.2)Three-dimensional reconstruction technology is used to obtain a three-dimensional model of each component material in the fiber-reinforced loess.The directionality and pore distribution of the fiber are used to describe the mesoscopic structural characteristics of the fiber-reinforced loess and the fiber diameter is corrected.At the same time,an approximate method is used The establishment of finite element models of fibers,solidified bodies and pores laid the foundation for the study of the mechanical properties of fiber-reinforced loess samples.3)In order to further study the effect of fibers on the physical properties of the specimen,a finite element model of fiber reinforced loess based on image processing technology was constructed.Based on MATLAB,fibers with different volume contents and different lengths were randomly placed and a finite element model was generated.The trabecular beam of 0.04m*0.04m*0.16m simulates the three-point bending test and performs finite element analysis.4)Through the combination of modeling software and numerical simulation software,the physical and mechanical properties of the asphalt mixture SMA-13 of the Guangdong-Hong Kong-Macao Bridge were evaluated using the numerical simulation method of the Brazilian split test.The meso-structure analysis is carried out,and the influence of pores on its macro-mechanical properties is analyzed quantitatively and qualitatively.At the same time,the mechanical parameters that have the same radial displacement effect under external load are studied,and the concept of equivalent elastic modulus is proposed,so that the mesoscopic structure of the concrete-macroscopic mechanical properties-mechanical material parameters are related,It is of great significance to design and study asphalt concrete and evaluate its performance.5)Use the 3D image processing software to restore the CT image to the greatest extent,complete the model construction of the asphalt concrete SMA-13 phases of the Guangdong-Hong Kong-Macao Bridge,and propose an analysis of the spatial distribution,mesostructure,and aggregate of concrete aggregates The three-dimensional visualization method of morphology,which deduces the gradation distribution curve of the SMA-13 sample,at the same time,introduces a grid model optimization method that can be used for numerical simulation calculations,which effectively reduces the total number of nodes and the number of elements.The quality and processing speed of the computer have been significantly improved,making it possible for large-scale numerical calculations.