Finite Element Numerical Simulation Analysis Of Modified Rammed Earth Wall Structures

In recent years,due to people's awareness of env ironmental protection,the pursuit of green building began to appear,so the study of raw earth construction is gradually increasing.Although the raw earth construction has such as energy saving and environmental protection,low cost,thermal insulation a nd other advantages,the earth itself has its own defects such as poor mechanical properties,disordered construction and lack of relevant building codes,that making it cannot be compared with the modern building structure s in bearing capacity and seismic performance.This paper focuses on the defects of the traditional rammed earth wall in mechanical properties.Through the field investigation,mechanical test and the numerical simulation method are used to analysis the mechanical performance and crack resistance of the rammed earth wall and the seismic performance of rammed earth farmhouse.First,the raw earth farmhouses in southwest region was investigated.Summarized and analyzed its main structural form,damage characteristics and seismic performance.Take the s ymmetrical-single layer-rammed earth farmhouse,most appearing during the investigation,as an example.Through adding fibers,curable powder and gravel to the earth to explore an effectively earth modification method that can improve the mechanical properties of rammed earth wall.Through mechanical test to seek the best solution among all the alternative options,Comparing the compressive strength test,shear strength test and tensile strength test of different modified materials,the modification method of 1% fiber 5% gravel(5mm,10 mm,15mm equal ratio)was determined to be the most effective one among all the alternatives.Using the finite element numerical simulation method to c ompare the displacement,cracking and destruction performances under the vertical load and monotonic horizontal load between the modified and unmodified rammed earth wall and compare the analysis of the seismic time-history response results between the modified and unmodified rammed earth farmhouse.The results show that the modification method of 1% fiber 5% gravel has significant effect on improvement of the bearing capacity and seismic performance of the rammed earth farmhouse.