Study On Evaluation Of Surrounding Buildings Affected By Precipitation Of Loess Foundation Pit Excavation

Super high-rise buildings are constantly emerging in densely populated areas of the city,with the emergence of a large number of deep foundation pit engineering.In the excavation of deep foundation pit dewatering process,extremely easy to cause the surrounding ground settlement and the surrounding buildings of buildings damaged,causing irreparable damage to persons and property.Therefore,in order to avoid risks and reduce losses in time,it is necessary to evaluate the impact of the surrounding buildings in advance.In this paper,the damage caused by the excavation of the foundation pit in loess area is the focus of the study,fuzzy comprehensive evaluation method and catastrophe theory evaluation method are used as research methods,finally,the results are compared with the actual situation,and some results are obtained.1.This paper summarizes the factors that affect the damage of surrounding buildings in the excavation of loess foundation pit.According to the rainfall on the surrounding built large excavation for foundation pit buildings damage data,summed up the impact of buildings the main factors of buildings damage for foundation pit design and construction,buildings its own characteristics,and the main factors are further subdivided into 12 sub factors.The results show that these factors play an important role in evaluating the degree of the damage of the foundation pit.2.Study on the influence of the fuzzy comprehensive evaluation on the damage of surrounding building.The effect of loess foundation pit excavation on the surrounding building damage is evaluated,the hierarchical structure system with the object of evaluation is established,the factor weight of the building damage is determined by the analytic hierarchy process,and the factors are divided into 4 grades,finally,combined with the theory of fuzzy mathematics,a fuzzy comprehensive evaluation model is established based on the effect of loess foundation pit excavation dewatering on the surrounding buildings,according to the masonry structure buildings around the foundation pit,the appraisal table of the degree of damage caused by the dewatering of the foundation pit excavation is designed,the rationality of the model is verified,the results show that the fuzzy comprehensive evaluation model can effectively judge the damage degree of the surrounding buildings,and is superior to the traditional empirical method.3.Study on the influence of catastrophe theory evaluation on the damage of surrounding building.Based on the catastrophe theory,the influence of buildings main factors of buildings damage(the pit design and construction,building its own characteristics)of multi-level decomposition,the data were normalized,combined with catastrophe progression theory,quantitative calculation,the damage evaluation model of buildings was established,The 4 levels of the evaluation of the damage of the surrounding rock in the excavation of the foundation pit are obtained,which are mild,moderate,serious and very serious.According to the masonry structure buildings around the foundation pit,the degree of damage of the building is designed and the rationality of the model is verified by an engineering example.The results show that the catastrophe progression model can effectively evaluate the influence of surrounding building damage.The model is simple and easy to operate,and has good operability and practicability.It does not use the weight of the factor index,and reduces the subjective supposition.4.Comparative analysis on the rationality of evaluation system.The advantages and disadvantages of the two evaluation methods and the two evaluation methods are compared and analyzed.The results show that the two methods can be used to evaluate the effect of the foundation pit dewatering on the surrounding buildings.5.The paper puts forward the engineering measures to reduce the ground subsidence caused by the excavation of the foundation pit and the damage to the surrounding buildings.The ground subsidence caused by dewatering of foundation pit based on the law,puts forward some engineering measures such as intermittent rainfall,the foundation pit waterproof curtain,recharge.The results show that these measures can effectively reduce the ground settlement and control the damage of surrounding buildings,and receive good results.