Irregular Structure Characterization Parameters And Compressive Performance Of FRP Grid Improved Tibetan Rubble Wall

At present,traditional Tibetan buildings in the form of stone and wood structures are still widely distributed in Tibetan areas.Most of these buildings use rubble masonry as loadbearing walls.The integrity of the rubble masonry is poor,and it is easily damaged under earthquakes.Therefore,it is considered that the FRP grid can be arranged in the horizontal ash joint of the rubble masonry to form a reinforced masonry and improve its mechanical performance.In order to learn more about the mechanical properties of Tibetan rubble masonry improved with FRP grids,it is necessary to carry out research on the pressure properties about this kind of masonry.The influence of the irregularity of the block leads to a large dispersion of the compressive strength of this type of masonry.It is necessary to introduce parameters related to the degree of irregularity of the masonry to predict its basic compressive strength.Based on this,the main research work of this paper is as follows:(1)Compression tests were carried out on 3 unmodified Tibetan rubble masonry and 3 FRP grid-modified Tibetan rubble masonry to obtain the ultimate compressive strength of the masonry and the major deformation characteristics and laws,and failure modes of masonry.(2)Introduce rubble size parameters,rubble shape parameters,masonry horizontal ash joint parameters and vertical ash joint parameters as the surface irregularity characteristic parameters of Tibetan rubble masonry.Based on the two convolutional neural network structures of OCRNet and Deeplabv3+,a model suitable for image segmentation of typical Tibetan rubble masonry surfaces is obtained by training.Based on the images of each specimen segmented by rubble and ash fractures,the calculation program for extracting the above characterization parameters was realized by using Matlab programming.(3)The above four characteristic parameters are linearly combined into the irregular parameters of the masonry by the weight coefficient,which is used to revise the calculation formula of the existing masonry compressive bearing capacity.The modified formula is used to predict the basic compressive bearing capacity of FRP grid improved Tibetan rubble masonry,so as to quantitatively evaluate the improvement of the compressive strength of Tibetan rubble masonry with different layers of FRP grid.