| Chinese annual new phosphogypsum emissions are about 50 million tons,and the two largest phosphoric acid bases in Guizhou Province,Wengfu and Kaiyang,emit 10 million tons of phosphate slag(phosphogypsum)each year.Industrial waste gypsum landfill will take up a lot of land resources.If it leaks into the ground along karsts and fissures,it will cause soil,surface water,and groundwater pollution.Modification and comprehensive utilization of industrial waste gypsum can turn waste into treasure,which can be used as a retarder for the production of cement,soil conditioner,or building decoration,etc.However,the consumption of gypsum in the above areas is limited and difficult to achieve The purpose of large-scale processing of industrial waste.Therefore,in this paper,phosphogypsum is used as a building material,and based on the theory of polyethylene enhancing the strength of phosphogypsum,the phosphogypsum-concrete mesh frame composite wall is taken as the research object,and the compression failure mechanism of the wall is analyzed through numerical simulation and test methods.The application of phosphogypsum in structural engineering provides a useful reference and opens up new ways for the resource utilization of phosphogypsum.This paper first uses finite element software to numerically simulate the polyethylene modified phosphogypsum-concrete mesh frame composite wall,the unfilled concrete frame wall,and the unmodified phosphogypsum-concrete composite wall,and compare the three types of walls.Mechanical properties.The results show that compared with the unfilled concrete frame wall,the bearing capacity of the phosphogypsum-concrete composite wall and the modified phosphogypsum-concrete composite wall are increased by 62.57% and 70.48%,respectively,indicating that the filled phosphogypsum can work together with the concrete frame and can Significantly improve the bearing capacity of the wall;in addition,when the wall steel bars yield,the corresponding displacement of the modified phosphogypsum-concrete composite wall is 59.11% higher than that of the unmodified phosphogypsum-concrete composite wall,indicating that the modified phosphogypsum is opposed to the wall The ductility of the body is improved,and the deformation of the modified phosphogypsumconcrete frame composite wall is more uniform and the ductility is better;by comparing the stress cloud diagrams of the three types of walls,it is found that the stress on the center pillars of the three types of walls under the maximum load is about 2 times that of the side column,and the existence of the filling material improves the force distribution of the concrete grid wall column,greatly reduces the ratio of the axial force of the center column to the axial force of the side column,and makes the force of the entire wall tend to be uniform.Greatly improve the possibility of wall loss of function due to local damage.Secondly,using similarity calculations,a 1/3 scale test model of polyethylene modified phosphogypsum-concrete mesh frame composite wall,unfilled concrete frame wall,and unmodified phosphogypsum-concrete composite wall was designed.The composite wall was subjected to a compression test with uniform loading on the top of the wall,and the mechanical properties of the three types of walls were compared.The test results show that compared with the unfilled concrete frame wall,the bearing capacity of the phosphogypsum-concrete composite wall and the modified phosphogypsum-concrete composite wall are increased by86.57% and 46.16%,respectively;compare the performance of the phosphogypsum-concrete composite wall before and after the modification The stress of the filling block(phosphogypsum before and after the modification),it is found that the strength of the filling block after modification is greater than that before the modification,and the contribution of the modified filling block to the overall force of the wall is also better than that before the modification;observation three The physical damage map of the group wall shows that there are no obvious cracks on the wall before the brittle failure of the unfilled frame wall and the phosphogypsum-concrete composite wall,while the modified phosphogypsum composite wall has a large number of cracks on the wall before the damage occurs.Horizontal cracks and oblique cracks show obvious ductility in the failure process;compared with the numerical simulation results,they are basically close.The larger error is the bearing capacity of the modified phosphogypsum-concrete composite wall.Finally,combined with the experimental analysis,from the perspective of the forcedeformation of the wall,the failure mechanism of the phosphogypsum-concrete composite wall before and after the modification is deeply studied,and the vertical load-bearing members of the wall are analyzed locally.Among them,the displacement meter that monitors the displacement of the wall floor beam and the vertical movement of the side column is studied in detail,the center column and the side column that are mainly subjected to the vertical load on the wall are subjected to force analysis,and the overall wall is divided into three Section and conduct sub-regional research.The results show that the load-stress curve of the middle column of the modified phosphogypsum-concrete composite wall is almost the same as that of the phosphogypsum-concrete composite wall,but the load-stress curve of the side column has a sudden increase,and the initial load of the sudden increase is 765 k N;At 765 k N—944.85 k N,the vertical displacement growth rate of the side column of the modified phosphogypsumconcrete composite wall is 37.5% higher than that of the middle column,indicating that the side column has greater deformation;the 2/3 section of the modified phosphogypsum-concrete composite wall The stress on the side column first decreases and then increases.The left column has the largest decrease and the maximum stress is only 11.91 MPa,which means that the left column of 2/3 section has local concrete fracture,prompting only the center column to bear all longitudinal loads in the later loading process.,Accelerate the damage of the wall,resulting in the modified phosphogypsum-concrete composite wall with lower bearing capacity than the phosphogypsum-concrete composite wall. |
PDF Full Text Request