Experimental Research On Mechanical Properties Of Grouted Stone Masonry Short Columns

Stone masonry structures are widely distributed in the southeastern coastal areas of China,but the traditional masonry methods generally exist such problems as unsaturated mortar and hollow lime joints,which result in excessive reliance on stone cushions to transmit force between stone blocks.The irregular shape of cushion blocks used in general masonry results in concentrated stress in stone blocks,which leads to premature cracking of stone blocks.In view of the above problems,this paper uses grouting material to strengthen stone masonry,and carries out the following related research:(1)In order to study the vertical compressive behavior of stone masonry after grouting strengthening,three groups of six specimens were made,with grouting material ratio and mortar strength as research parameters.The vertical compressive bearing capacity of the specimens was tested.The test results show that grouting strengthening can effectively improve the vertical bearing capacity of stone masonry.Two different ratios of grouting strengthening specimens are 68% and 106% higher than that of the non-strengthened specimens,respectively.Grouting strengthening can improve the vertical stiffness of specimens,and the higher the grouting material ratio,the greater the lifting effect of specimens.The failure of grouting strengthened specimens in vertical compression test shows brittle failure characteristics.(2)In order to study the effect of grouting strengthening on the horizontal shear capacity of stone masonry,three groups of six specimens were made,and the shear capacity of the specimens was tested under shear-compression combined action,taking the proportion of grouting material and the strength of mortar as the research parameters.The results show that grouting strengthening can also improve the shear bearing capacity of stone masonry.The results show that grouting strengthening can also improve the horizontal shear bearing capacity of stone masonry.Under the condition of high-strength mortar masonry,the bearing capacity of 10% grouting strengthened specimens is 26% higher than that of 12% grouting strengthened specimens;under the condition of low-strength mortar masonry,the bearing capacity of 10% grouting strengthened specimens is 33% higher than that of 12% grouting strengthened specimens.The effect of grouting strengthening on horizontal shear rigidity of stone masonry is similar to that of vertical compressive rigidity.In the shear test,two nonstrengthened specimens exhibit shear-friction failure,while four strengthened specimens exhibit diagonal compression failure.The failure process occurs rapidly and has obvious brittle failure characteristics.(3)Using ABAQUS finite element software,the vertical compressive and horizontal shear experimental of strengthened stone masonry are analyzed by means of separated modeling.Based on the original model,the influence of grouting filling rate,number of cushions and other parameters on the compressive capacity of original stone masonry is studied.The simulation results show that the finite element separation model can well simulate the mechanical behavior of stone masonry under compression and shear.The simulation results of compressive test parameters show that increasing the strength of grouting material and masonry mortar can improve the vertical compressive bearing capacity of specimens.Increasing the stone cushion block has no obvious effect on the vertical compressive bearing capacity of specimens.The filling rate of grouting material has a greater impact on the compressive bearing capacity of specimens.The lower the filling rate of grouting material,the smaller the vertical bearing capacity of specimens.(4)Based on the results of finite element simulation analysis,the formulas of vertical compressive and shear bearing capacity of strengthened stone masonry are deduced,respectively.Comparing the theoretical calculation value with the test result,the formulas of compressive and shear capacity of stone masonry strengthened by grouting are obtained.