Experimental Study On Improving The Performance Of Raw Soil Materials Based On Physical And Chemical Modification

Raw soil buildings will exist for a long time as an important traditional form of residential buildings in my country’s villages and towns due to their low cost,warm in winter and cool in summer,low energy consumption and environmental friendliness.Aiming at the problem of low strength of raw soil materials and damage to the renewability of raw soil by modification methods such as cement,fly ash and other materials,a physical and chemical modification plan based on the property of repatriation is proposed.The contaminated waste modified raw soil can be returned to the farmland for the second time and continue to be used for agricultural planting to realize resource reuse.This article will focus on the technical scheme of raw soil material physical and chemical modification based on the landability,and analyze the mechanical properties of raw soil masonry,the improvement effect of raw soil wall seismic performance and the compressive constitutive relationship with the modification scheme.The main work and conclusions are as follows:(1)In order to improve the compressive and flexural strength of raw soil materials,non-toxic and harmless modified materials are used to carry out physical and chemical modification orthogonal experiments,and the modification mechanism is discussed in combination with microscopic detection.The optimal ratio of modification was obtained through research: 0.8% for water glass,0.4% for potassium alum,1.2% for urea,2% for redispersible latex powder,0.4% for straw,and 1% for water reducing agent.The flexural strength of the test block under the modified optimal mix ratio is 1.77 MPa,an increase of40.4%,and the compressive strength is 5.12 MPa,an increase of 50.1%,and its strength is equivalent to that of the small concrete hollow block MU5.The increase in the strength of raw soil materials is mainly due to the comprehensive physical and chemical interaction between the modified material and the soil,forming a soil skeleton structure supported by silicate gels and crystals,which is manifested as an increase in the strength of raw soil materials on a macroscopic scale.(2)In order to study the Return to farmland of the modified soil under the modification scheme,through the comparative analysis of the main control beneficial and harmful index detection and planting test of the soil by the testing agency,various data show that the modified technical scheme will not damage the soil Structure,the main beneficial indicators of the modified soil basically meet the technical standards of green planting,and all the harmful indicators are within a reasonable range.In the planting test where the modified soil accounts for 0%,50%,and 100%,each soil is The emergence time,emergence rate and plant height of the crops under the combination ratio are similar,indicating that harmless return planting of the modified soil can be achieved.(3)By comparing the compressive test of modified masonry and plain soil masonry and the shear test along the joint,the research results show that the compressive strength of plain adobe brick masonry and modified adobe brick masonry are 0.874 MPa and 1.077,respectively MPa,the compressive strength of the modified masonry is increased by 23.2%,and the damage displacement of the modified masonry is increased compared with that of the plain soil masonry as a whole,that is,the ductility of the modified masonry is improved;The shear strength of plain soil masonry and modified raw soil masonry along the joint is 0.0291 MPa and 0.0341 MPa respectively,and the shear strength of modified masonry is increased by 17.18%,which indicates that the material modification scheme has a good effect on improving the mechanical properties of raw soil masonry.(4)Through the pseudo-static test of the modified raw soil wall and the plain soil raw soil wall,the test phenomenon,failure form and hysteresis curve of the two walls are analyzed.The research results show that: the modified raw soil wall and the plain soil raw soil wall The test phenomena of the soil wall were similar throughout the process,and finally formed through oblique cracks and shear failure;the peak load and ultimate load characteristic points of the modified green soil wall were increased by 19.7% and15.7% respectively compared with the plain soil wall.The bearing capacity of the rear wall has been improved,and the ductility and energy consumption of each load characteristic point have also been improved to some extent,indicating that the material modification scheme has a good effect on improving the seismic performance of the raw earth wall.(5)In order to establish a constitutive equation of raw soil that meets the characteristics of raw soil materials and has certain applicability,the research results are obtained through uniaxial compression tests of raw soil materials under different working conditions and comparative analysis of constitutive equations of existing raw soil materials at home and abroad.It shows that the important feature of the stress-strain curve of raw soil material under compression is that the curve has an initial concave section.The modified constitutive equation can achieve a better simulation of the test curve of this experiment and other researchers through the change of parameters.According to the relationship between the strength of the raw soil material and the parameters of the constitutive equation,the proposed formula of the constitutive equation of the raw soil material under different strength intervals is established,and the constitutive relationship database of the raw soil material is initially formed.