Improved Optimization Of Load-Bearing Rammed Earth Wall

Raw soil building construction is not only in our country,but also used oldest and most widely distributed form of traditional architecture in the world.This structure has a series of advantages: using local materials,b iodegradable renewable,simple construction,low cost,outstanding thermal performance,low energy consumption and pollution-free.The research of its wall performance has a great significance to the structural design.T hrough to the bearing wall oframmed earth’s literature and field investigation,analyze the wall damage feature and bearing capacity,beside discuss the effect factors of the wall shear bearing capacity,put forward the formula for calculating the shear bearing capacity of rammed earth wall.Aiming at the defects of the material on the mechanical and water resistance propert y which is made by adding the clay petrochemical agent to improvethe optimization and use the finite element method to simulate the mechanical properties of the wall under horizontal shear,related work and conclusions are as follows :1.Through to the bearing wall oframmed earth’sfield investigation in parts of Sichuan,gained the related information the local raw soil building wall structure form of the village,building materials,construction technology and quality disease.The wall structure form have adobe walls and rammed earth wall,in the aspect of building materials us e cohesive soil and mixed with sand,gravel,stone chips two kinds,the soil wall construction technology has built and mud brick rafter,the wall damage caused by mainly reflected in several aspects: the foundation and improper handling of foundation,insufficient bearing capacity of wall,improper construction measures,irregular structure system,the natural factors and long-term use.2.Analyze the effectof vertical pressure,high aspect ratio,the rammed earth material for the shear capacity of the adobe building,due the rammed earth wall shear failure mode fit the shear frictiontheory to establish the formula for calculating the shear bearing capacity of rammed earth walland put forward some suggestions of the seismic measures from the aspect of selection of materials,selection of wall size,construction measures and construction technology.The studying is obtained which with the increase of the vertical pressure is as same as the shear bearing capacity of the wall,but the vertical pressure will appear the shear destruction of predominantly compressive damage,Height to width is smaller,improve the shear bearing capacity and stability of the wall,the height to width is larger,the wall of shear bearing capacity is low which is prone to collapse of lateral tilt,the more changer of moisture content,the moreof the drying shrinkage cracks on wall and its shear strength is weaken obviously,the increase of the cohesive force and Angle of internal friction onthe rammed earth materials,which can improve the shear bearing capacity of the wall.3.By mixing the different raw soil materials with the clay petrochemical agent,the study found that the clay petrochemical agent have the improvement of obvious effect for the compaction function,shear strength and water resistance performance,establish modeling of rammed earth wall shear bearing capacity containedthe clay petrochemical agent,finally simulate of shear test,verify the accuracy of the simulation.Experiment shows that with the increase of clay petrochemical agent content,the maximum dry density of soil is increases,the optimum moisture content is reduced,shear strength and water resistance was improved accordingly,the effect of loess is better than that of the clayand the numerical simulation shows that its results is not more than 10% with the actual test value which verify the feasibility of simulation.4.Through finite element simulation analysis under different clay petrochemical agent dosage and different soil samples of load-bearing rammed earth wall under the action of vertical load and horizontal shear situation,the research on the mechanical properties and the load deformation.T he simulation found mixed clay petrochemical agent wall about the shear strength is higher than the soil wall,and clay petrochemical agent improve shear strength of the wall and the loess is better than the clay wall,for the deformation of the wall,the clay petrochemical agent has obvious improve effect,the loess wall is better than the clay wall.