Study On Mechanical Property And Numerical Simulation Of Gradient Raw-Soil Based Wall Materials

Raw-soil is that processed simply and has not been roasted. Raw-soil material has many superior performances, for example, thermal insulation, humidity-conditioning,economy, and it can return to nature after finish its job, however, the application and development of raw-soil construction is limited by its deformation and low strength.Raw-soil may become one of the most important building materials if we can increase its strength and water resistance by technical means and reasonable structure design.The researches on raw-soil materials modified by plant fiber and inorganic cementitions materials respectively showed that the appropriate proportion of jute fiber is0.2wt.%, and the mass ratio of cement/coal ash/slaked lime was 5:3:2.The results indicated that the bending and compressive strength of the test block both increase compared the raw-soil birquettes modified by inorganic cementitions materials. It also showed that the 7days and 28 days flexural strength and compressive strength of compound modified row-soil material increase as the added inorganic cementations materials increasing; and the growth rate of the bending and compressive strength in28 days were higher than t 7days strength.The gradient design was conducted for the structure of the raw-soil briquette, The flexural strength, compressive strength and force-displacement relationship of the gradient briquettes were determined in the laboratory. The test showed that the flexural strength and compressive strength of gradient briquettes were both increased compared the uniform birquettes which contain the same volume of the inorganic cementitious materials, and the increase of blending strength was more apparent. The 28 days blendingstrength and compressive strength of these birquettes which had the same gradient difference between the adjacent two layers were both increased compared the uniform birquettes which contain the same volume of the inorganic cementitious materials, but the rate of increase of the flexural strength of gradient briquettes compared the uniform birquettes which had the same volume of the inorganic cementitious materials descend.The finite element simulation was carried out by numerical analysis software on the gradient briquettes and their corresponding layered briquettes which contain the same volume of the inorganic cementitious materials. The comparison of the simulation result indicated that the total displacement and the Components of stress, strain and displacement at different directions of gradient briquettes were lower than these of layered briquettes. the maximum displacement of layered briquette is 4.32 times in X direction, 1.94 times in Y direction and 2.27 times in Z direction of the corresponding gradient birquettes, the maximum strain of the layered briquettes in the direction of X, Y,and Z is respectively 1.91 times, 1.99 times and 1.79 times of the gradient briquettes; the maximum normal stress of the layered briquettes in the direction of X, Y, and Z is respectively 1.94 times, 1.30 times and 1.42 times of the gradient briquettes; compared the corresponding layered birquettes, the gradient structure can obviously improve the shear stress in XY direction; and the maximum Shear Stress of the layered briquettes in the direction of X, Y, and Z is respectively 7.05 times, 1.58 times and 1.09 times of the gradient briquettes;...