Material Performance Testing And Visual Collapse Simulation Analysis Of The Great Wall Of Masonry

The Great Wall is an important cultural and historical heritage of China,and an important carrier of national self-confidence.So far,the repair of the Great Wall is almost always based on experience and lacks the basis of analysis based on modern mechanics.In order to improve the repair and protection of the Great Wall of masonry and to provide a theoretical basis for the repair design of the Great Wall,this project will use static tests to test the performance of the Great Wall bricks,mortar,soil and other materials,and perform a collapse simulation analysis of the Great Wall based on Blender visualization software.The main research contents and results are as follows:(1)Sampling of Great Wall bricks,mortar and soil will be carried out,and static tests will be conducted on Great Wall bricks to obtain the density,compressive strength and elastic modulus of Great Wall bricks;single-joint shear test and interfacial friction test will be conducted on mortar to obtain the shear strength and friction coefficient of mortar;triaxial unconsolidated undrained shear test will be conducted on soil to obtain the cohesion and internal friction angle of Great Wall fill.(2)Non-destructive testing was conducted for the Great Wall bricks and mortar.Ultrasonic and rebound nondestructive tests were performed on the Great Wall bricks to obtain their sound velocity and rebound value distributions,and the rebound strength curves of the Great Wall bricks and the strength curves of the integrated ultrasonic rebound method were obtained by fitting.The penetration test was performed on the Great Wall mortar,and the penetration values of the foundation grout mortar,stone hook mortar and brick mortar were obtained.The penetration values revealed that the strengths of the three mortars increased sequentially,among which the compressive strength of the hook mortar was similar to that of the masonry mortar at the age of 400 d,and the compressive strength of the brick mortar was similar to that of the mortar.(3)The basic principle of the physical engine is introduced and verified.Blender software is used for block unit modeling,and the simulation analysis of the masonry Great Wall enemy platform base and enemy platform internal arch ring is carried out,and the feasibility and accuracy of Blender software for the Great Wall collapse simulation method is verified by comparing the simulation results with ABAQUS software and the current situation.(4)Blender software was used to establish the original dimensional model of the masonry Great Wall enemy platform base and to study the influence of five factors on the safety of the Great Wall,such as internal filler soil cohesion and corner tie stones.Through the visualization simulation results and related data presented by Blender software,the following conclusions are obtained:(i)the overall stability of the enemy platform decreases as the cohesive force of the internal filler soil decreases;(ii)some of the corner bars are ding stones,which have a tie effect,and their displacement does not change significantly when the enemy platform undergoes large deformation.Blender software was used to predict four kinds of damage states of the existing masonry Great Wall: external bulging of the foundation wall,missing internal rubble of the strip stone layer,missing lower rubble of the stepping layer of the slope section,and inward tilting of the palisade wall.The results of the visualization simulation show that three types of damage,namely,external bulging of the foundation wall,missing internal rubble exposure in the stone layer and missing lower rubble exposure in the slope section,will cause extensive collapse of the Great Wall and should be repaired in time;the inward tilting of the palisade wall will only affect the local treads of the Great Wall,which can be repaired relatively quickly.