Analysis Of The Mechanical Mechanism Of The Pull Beam Of The Pile Cap Of The Raw Material Field On The Soft Ground

In coal,metallurgy and other industries,because the design capacity needs to build raw material yard,strip yard is widely used.Strip yard covers a large area and requires high foundation bearing capacity.The upper structure of stockyard is usually reticulated shell structure.The reticulated shell structure is sensitive to the change of external factors,and the stability problem is more prominent.The uneven settlement of foundation system has the most prominent impact on the overall stability of the structure.The arrangement of tension beams between the bearing platforms of the foundation has a significant effect on enhancing the integrity of the foundation system,ensuring the uniform stress of the foundation system and controlling the uneven settlement.In this paper,the mechanical properties of the bearing platform tension beam in the strip yard system on the deep soft soil foundation and the upper structure of the latticed shell structure are studied（1）This paper analyzes the important role of bearing platform pulling beam in material yard system,summarizes the adverse effect of soft soil foundation on bearing platform pulling beam in material yard,and systematically summarizes the research status of bearing capacity and mechanical performance of bearing platform pulling beam in material yard.（2）The bearing capacity of the bearing platform of the raw material yard is analyzed theoretically.The calculation formula of the material pressure distribution on the top of the pull-down beam without considering the differential settlement between the pull-out beam and its two sides of the ground is obtained by curve fitting,and the calculation formula of the material pressure distribution on the top of the pull-down beam considering the differential settlement is obtained by adjusting the parallel wall theory.Based on the analysis of the basic mechanics theory,the calculation formula of the axial force of the latticed shell structure on the bearing platform and the frictional resistance of the foundation on both sides of the beam are obtained.The Winkler foundation model is used to analyze the foundation reaction of bearing platform tension beam.Finally,based on the above analysis results,the composite stress model of bearing platform tension beam is obtained.（3）Based on the similar principle,the scale model test of bearing platform tension beam is designed.The soft soil foundation is simulated by using the sponge material after deformation measurement.The members of bearing platform tension beam are poured by concrete,and the test is carried out by using the pile material determined by the physical and mechanical property parameters.The vertical material pressure and the ground material pressure of the upper part of the beam are pulled down in the process of gradual stacking and the difference settlement between the ground and the pull beam on both sides after the stacking is completed.The material pressure value measured by the test is analyzed,and the distribution rule of the material pressure of the pull beam and the upper part of the ground on both sides,the change rule of the material pressure of the pull beam along the axial direction in the process of gradual stacking and the influence range of the soil arch effect are obtained.According to the different types of stacking materials in the strip yard,the filler shall be replaced during the test,and the pressure difference between the stone and coal materials shall be compared.（4）Using the DEM software edem to establish the drawbench scale model of the stock yard,calibrate the parameters of the test pile,and measure the vertical material pressure distribution on the upper part of the drawbench when setting the different settlement and differential settlement rate between the two sides of the ground and the drawbench.The change and distribution of the material pressure on the upper part of the tension beam in the process of settlement are analyzed.The distribution form,settlement amount and settlement rate of the upper material pressure along the axial direction of the pull-down beam under the action of triangle cross-section stacking（standing）are obtained.During the test,the filler was replaced and the pressure difference between stone and coal was compared.（5）According to the background engineering example of this paper,the finite difference program FLAC^3D is used Based on the interaction between bearing platform pulling beam,pile foundation and foundation,the paper analyzes the stress and deformation of the foundation,pile foundation and bearing platform pulling beam under two loading conditions of gradual stacking and gradual unloading in the operation of the material yard.On this basis,the relevant variables in the material yard system,such as stacking load（stacking rate,stacking load section）,rigidity of the pulling beam and gravel pile composite foundation,are set up（rigidity of sand gravel cushion,length of gravel pile,arrangement form of gravel pile,rigidity of gravel pile）,nature of soft soil foundation and inclination degree of inclined pile,etc.,analyze the influence of relevant variables on bearing platform tension beam force and deformation,and then get the material field optimization analysis based on tension beam protection.（6）Based on the geological conditions and monitoring data of the background material yard project,combined with the deformation and mechanical characteristics of composite foundation,foundation system and bearing platform tension beam in the material yard system obtained from the numerical calculation,the damage mechanism of bearing platform tension beam is analyzed,the damage reason of the tension beam is determined,and the safety analysis and repair suggestions of bearing platform tension beam in the material yard are put forward.