Analysis Of Vibration Pressure Forming Characteristics Of Model Test Rock Mass And Development Of Three-dimensional Similarity Reconstruction System

Physical model test is an important means to study the mechanism of underground engineering disaster evolution and safety prevention and control.At present,the traditional model rock production process has long production cycle,labor intensity and other problems,has been difficult to meet the requirements of large-scale physical simulation test,seriously restrict the development of model test technology.3D printing technology,3D printing technology is a rapid prototyping technology,through the accumulation of layer-by-layer spraying stack to construct three-dimensional solid structure,has been widely used in aviation 3D printing technology is a rapid prototyping technology to construct three-dimensional solid structures by stacking layer by layer spraying,which has been widely used in aviation,medical,machinery,construction and other fields.However,the existing model rock 3D printing device is mainly based on paste material self-bonding molding,there are problems such as slow molding speed and uncontrollable molding.Therefore,this paper innovatively combines vibration compaction molding technology with 3D printing technology,proposes and designs a vibration compaction molding 3D printing system applicable to multi-component weakly cemented similar materials,and provides a new process for model rock body production of 3D geological reconstruction,and the main research contents are as follows:(1)Firstly,the forming method of similar materials and the principle of vibration compaction are analyzed and explained.Combined with the structure and vibration model of vibration compaction molding machine,the mechanism of vibration compaction process on the pressed material is explained theoretically.According to the actual situation of vibration compaction molding machine,the vibration compaction parameters are explained,and the main vibration compaction parameters are determined:excitation frequency(vibration frequency and excitation force work together,in the form of vibration frequency)5-25Hz,static surface pressure 2.1-3.3kN,vibration time 30-150s,which provides a theoretical basis for subsequent test arrangement and vibration compaction device design.(2)The effects of vibration frequency,excitation force,vibration time,static pressure and other vibration compaction parameters on the physical and mechanical properties of similar material forming specimens were studied by orthogonal test system.The results were analyzed by range analysis,variance analysis and multiple regression analysis.The results show that the vibration frequency and excitation force have a great influence on the physical and mechanical properties of similar material forming specimens.The regression model of the influence of vibration compaction parameters on the physical and mechanical parameters of forming specimens is obtained,which provides experimental data support for the production of large model rock mass.(3)Based on the characteristics of the weakly cemented similar materials,the structural design and control system of the 3D similar reconstruction system of the model rock are completed by combining the application of vibration compaction technology and 3D printing technology.The similar material is vibrated and compacted into shape by a specially designed vibratory compaction device,and the model rock body is printed in 3D with the cooperation of 3D mobile frame.Based on the above equipment,the 3D geological reconstruction process of the physical model rock body is proposed,and the 3D geological reconstruction of the homogeneous model rock body is realized;and the feasibility of the equipment is verified through actual printing tests.This paper initially explores the application of vibration compaction molding technology on 3D printing process,realizes the 3D similar reconstruction of model rock,and advances the application of model test method in the field of underground engineering disaster prevention and control.It is believed that with further research,it will eventually greatly promote the development of underground engineering disaster prevention and control technology.