| Pagoda is not just a historical and religious architecture,and also is the ancient Chinese high-rise building model.It shows the history of ancient architecture materials,construction technology and other aspects of the history,also witnessed the history of the times,culture,art,religion,social and economic aspects of the development process.China's existing Pagoda structure has a long history,and it has seriously influenced by natural disasters and man-made destruction.So it resists disaster's ability is poor,and needs repaired and protected urgently.However,due to the particularity of the protection of masonry pagoda,the research on its protection theory and technology is still imperfect and needs more in-depth study.In this paper,we used the small wild goose pagoda as the research object,and studied the non-destructive performance enhancement technology of pagoda with the small wild goose pagoda,which is based on the related experimental study of ancient mortar and performance enhancement materials,.The main work is as follows:(1)With reference to historical literature and production technology,the ancient glutinous rice mortar,ancient mortar mortar and ancient mortar were selected as the substrate,modified epoxy resin,methyl methacrylate and methyl sodium silicate as the performance enhancing material.Through simulated analysis and orthogonal test design,we made a total of 24 groups of 108 ancient glutinous rice mortar,ancient Ma knife mortar,ancient mixed mortar cube test block and prism test block,which substrate cube test block 3(a total of 9),Each of the six pieces of prism test pieces(18 pieces in total)were immersed in each of the cubes of the modified epoxy resin,methacrylic acidmethyl ester or methyl silicate property enhancing material(Total of 27),prism test block of the six(a total of 54),and carried out the corresponding mechanical performance test and analysis.The results show that the cube compressive strength and prismatic peak stress of the three kinds of ancient mortar are low,and the properties of the modified mortar are improved after immersion in the modified epoxy resin,methyl methacrylate and methyl silicate.The compressive strength of the cube and the peak stress,peak strain,ultimate strain and elastic modulus of the prism are obviously improved.The compressive strength of the cube increases by about 18.8-60.0%,the peak stress of the prism is about17.5-40.7%.And the objects immersed in modified epoxy resin and methyl methacrylate are improved more obvious.(2)Based on the test and analysis of the ancient mortar and the performance of the ancient mortar,the ancient brick and the ancient glutinous rice mortar were selected as the base material,and 9 groups of 54 simulated masonry specimens were prepared as shear specimens.The modified epoxy resin and methacrylic acid methyl ester were used as the performance enhancing material,6 sets of 36 specimens of the ancient masonry were taken from the prepared test pieces and 6 groups of 54 ancient masonry.The non-destructive performance of the base material was enhanced by the infiltration method,and the corresponding performance test was carried out,and the feasibility of the infiltration method of the ancient masonry substrate was studied.The results show that the two kinds of performance enhancing materials can obviously improve the compressive strength and shear strength of the ancient masonry substrate,the improvement is about 6.0-40.5%,and stress-strain curve of the old masonry immersed in Oxygen resin or methacrylic acid methyl ester masonry were fitted,and the corresponding constitutive model was established.In addition,the examination of masonry specimen mortar showed that the non-destructive repair performance enhancement material could be fully immersed in the consolidated ancient mortar,and the immersion effect was good.(3)Eight ancient masonry wall specimens with thickness of 240 mm,370mm and490 mm were fabricated by using the ancient green brick and the ancient glutinous rice mortar as the substrate,and the modified epoxy resin and the methyl methacrylate wereused as the performance enhancing material.Among them,three different thicknesses walls(240mm,370 mm,490mm)were immersed in modified epoxy resin,and two different thickness walls(240mm,490mm)were immersed in methyl methacrylate.The failure mechanism of the ancient masonry walls was studied under low cyclic pseudo-static experiment,and crack load,failure load and the energy dissipation capacity are studied,and the corresponding restoring force model is established to determine the equivalent damping ratio of the specimen.The results show that the crack load,the failure load and the energy dissipation capacity of the wall specimen with different thickness are improved to some extent,the deformation ability and lateral resisting stiffness of the wall specimen with different thickness are also improved.The results show that the immersion of modified epoxy resin or methacrylic acid methyl ester can obviously improve the seismic performance of the ancient masonry wall,and it can be used for the enhanced performance and earthquake resistance of the masonry tower structure.In addition,the test results also show that performances of wall specimen immersed in modified epoxy resin are better than methyl methacrylate.(4)Considering comprehensively the cultural value and protection significance of Small wild goose pagoda,and detailed refer to the historical repair archives,and study on the strength characteristics of structural materials,repairing characteristics and damage status of Small wild goose pagoda.The dynamic characteristics of the Small wild goose pagoda structure were tested on site,and the dynamic characteristics and dynamic catastrophe characteristics of the structure were analyzed.And then,the finite element model of Small wild goose pagoda structure is established,and finite element analysis of dynamic characteristics and dynamic response of Small wild goose pagoda under different acceleration earthquakes.We also study on the combined method of ultimate bearing capacity and ultimate displacement is used to evaluate the seismic performance of Small wild goose pagoda structure.(5)According to the similarity theory of model structure design,a small geese model with geometric similarity ratio of 1/10 was designed and constructed.The impregnation method was used to immerse the modified epoxy resin and the local structure was modified.The base material model and the non-destructive performance model were used to simulate the seismic shaking table in 26 kinds of workingconditions.The relative acceleration and displacement response of the different models of the tower model and the non-destructive performance model under earthquake were studied,and the main Characteristics and Variation of Seismic Response of Model Structure.The results show that the displacement response of the performance enhancement model has a significant decrease in the tower under the earthquake,especially in the middle of the tower,and the displacement response at the top of the tower is generally about 20%.Under the same conditions and the 8 degree earthquake,the performance enhancement model has almost no cracks,but the original model structure has been cracked at 8 degree earthquake.(6)Based on the prototype structure data of small goose pagoda,the simulation model of the prototype structure of pagoda was established by ANSYS finite element software.The prototype structure of the pagoda was calculated under multiple operating conditions,analysed the effects of the structure of the substrate and the immersion method which Immersed separately in the modified epoxy resin and the methacrylic acid methyl ester enhanced material under the 8 degree earthquake,and discussed the effect of non-destructive performance of the prototype structure of the pagoda.The results show that the modified epoxy resin and methyl methacrylate can enhance the displacement response of the pagoda to about 30% under the 8 degree earthquake.The results of the study not only provide a new method for the earthquake protection of the pagoda,but also apply to the improvement of the performance of the masonry pagoda,which have a certain engineering application practice vision. |
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