Research On Risk Analysis And Control Of Tile Shedding Of Building External Insulation Finish Layer

As the external insulation wall is approaching the design life,the existing building external insulation wall finish layer tiles off has become the norm,tile shedding problem needs to be solved.This paper analyzes the current situation of shedding of existing building walls and the volume of shedding through research,and carries out risk assessment of factors affecting the durability of external insulation walls by using the combined assignment method-cloud model.Based on the results of risk assessment,numerical simulation analysis is carried out for the indicators with higher risk degree,and governance measures for the problem of shedding of tiles of external insulation wall finishes of existing buildings are proposed,taking Xi’an city as an example,to provide suggestions for the rectification of external walls of existing buildings in Xi’an.This paper covers the following main topics:(1)grasp the status of existing building facade tile shedding.Through a three-month mapping survey of tile shedding on the exterior walls of Xi’an,the current situation of shedding such as the degree of tile shedding,shedding parts and consequences of shedding on the finish layer of existing buildings was statistically analyzed,the hazards of tile shedding were analyzed,and the trend of tile shedding was predicted by using gray prediction algorithm.(2)Risk analysis of factors affecting the durability of external insulation walls.According to the research to grasp the situation of building exterior tile shedding,establish the risk evaluation index system affecting exterior tile shedding and build the accident cause structure map.Screening of accident causation node indicators in accident causation structure diagram based on graph theory method.Risk analysis of indicators using the risk assessment method of combined assignment method-cloud model to determine the risk level of indicators,where the indicators with higher risk level are: bonding layer adhesion performance,temperature,hot and cold alternation,wind pressure,and irregularities in construction personnel operation during patching.(3)Finite element software(ABAQUS)was used to further analyze the effect of indicators with higher risk levels on the durability of the exterior insulation system.The results show that:Under the action of wind load,the corner part of the external insulation wall finish layer tiles have the largest displacement perpendicular to the direction of the wall;Under the action of different temperatures,high temperature causes the outer insulation wall finish layer tiles perpendicular to the wall direction displacement changes are most obvious;bond strength intact and bonding material aging serious two states of the insulation wall in the role of temperature,wind load,bonding material aging serious wall finish layer tiles perpendicular to the wall direction displacement degree is greater;Different broken area of the wall under the influence of environmental factors,the larger the broken area of the wall around the finish layer tiles perpendicular to the direction of the wall more obvious displacement.(4)For wind load,temperature impact on the external insulation wall proposed control measures.Through the neural network prediction model,we analyze the time when the displacement of the external insulation wall finish layer tiles perpendicular to the wall direction under the action of temperature reaches the limit threshold and establish the monitoring and control mechanism.According to the numerical simulation analysis of different heights and different wind levels,the displacement of the external insulation wall finish layer tiles perpendicular to the wall direction reaches the limit threshold conditions,and the corresponding control measures are proposed for the wind situation.Finally,based on the analysis of the research data,a risk inspection system was established to provide a reference for the control of the facades of existing buildings in Xi’an.