Study On Strengthening Rammed Wall With Fiber Composite Soil Plaster Based On Historical Building Protection

In the remote economic underdeveloped areas of Northwest China,where are still survives lots of historical buildings with rammed earth.These buildings have destroyed seriously because of many years of salt erosion,rain erosion,ultraviolet aging,freeze-thaw and so on.When the earthquake happens for the remote areas,rammed earth buildings will be destroyed then collapse,that seriously affect the safety of people’s lives and property All.Based on the investigation of the damage status of rammed earth buildings in Northwest China and the analysis of the damage factors and mechanism,this paper puts forward a strengthening scheme of steel wire mesh or nylon mesh fiber composite soil plaster,which can put armor on the wall surface to resist the impact of the damage of the buildings,and then improve the shear bearing capacity of the wall without obvious modern reinforcement traces To "repair the old as the old" purpose.In order to ensure strengthened rammed earth wall has good strength,durability,seismic performance and so on.First of all,the strength and durability of the plaster material fiber composite soil were studied.With plain soil as raw material,po42.5cement,PVA fiber,soil curing agent,polymer(cold soluble polyvinyl alcohol)as modified admixture,and with fiber content and model,soil curing agent content and type,polymer content as variable groups,mechanical properties and durability tests were carried out.The test results show that the mechanical properties and durability of group C fiber composite soil are relatively best.In the wall strengthening experiment,steel wire mesh or nylon mesh and C-group fiber composite soil plaster were used to reinforce the wall.After the maintenance,diagonal loading was carried out to study the broken ring shape and damage characteristics of the reinforced wall.The shear strength and stiffness degradation of the walls with different reinforcement methods were evaluated and analyzed.The results showed that the reinforcement indexes of the rammed earth wall with steel wire mesh inclined reinforcement were relatively good The shear strength of each wall is calculated,which has a high degree of compliance.The ABAQUS finite element software is used to build the model of each diagonal loading specimen,and the validity of the model is verified by comparing with the test.The finite element model of reinforced bearing rammed earth wall is established,the shear resistance and failure mechanism of each reinforced wall are analyzed,and the influence of steel wire diameter,mesh size of steel wire mesh and thickness of reinforcement layer on the shear capacity and deformation capacity of the wall is simulated and analyzed.According to the formula of load-bearing wall in masonry code,the shear capacity of each reinforced wall is calculated,and the corresponding reinforcement suggestions are given.