Study Of The Safety Assessment Method Of Influence Of Foundation Excavation On Nearly Buildings

With the accelerating development of urbanization in China, city increasinglycrowded problem become more and more obvious. To the underground and high-risedevelopment is one of the best ways to solve the problem. And also a number ofhousing built in the sixties and seventies needs renovation, which accounted for themajority of brick and concrete. This kind of structure is very sensitive to the foundationsettlement. Therefore, on one hand, foundation pit engineering constantly refresh thedifficulty and depth. On the other hand, around the pit face a large number of intensiveconstruction and pipeline which need to be protected. In actual engineering as thefoundation and surrounding environment complexity, its failure often occurs. Therefore,the study of the influence of foundation pit excavation on nearly buildings has becomean important issue.This paper does study on the influence of foundation pit on buildings combinedwith the practical research and treatment of brick and concrete structure damage underthe influence of foundation pit. It studies the deformation of foundation pit, mainly theinfluence on the surface subsidence at the top of slope, and tries to find the variationrule. The stress and damage cracking of buildings nearby are discussed under thesurface settlement. A evaluation model based on cracks is given. Finally this paperstudies the damage influence degree of the foundation pit on adjacent buildings from theoverall and gives an evaluation model. The main contents are embodied in the followingpoints:Firstly, this paper has derived the stress and strain of surrounding soil on elasticmechanics theory under the influence of foundation excavation with the external load. Itincludes the solution of stress and strain of the soil and values of ground surfacesettlement.Secondly, this paper establishes a model of foundation pit excavation with piles assupporting structure using numerical simulation software FLAC3D and analysis onsurface settlement of foundation pit excavation. It makes a comparative analysis of theground settlement curve based on numerical and analytical solutions above. Theanalysis has been made about the ground settlement curve on condition of differentdepth of foundation pit excavation. This paper also discusses ground settlement curve ofthe different distance from load to foundation pit and tries to find a safe distance from the building foundation pit and tries to find the impact range of foundation pit on the topbuilding.Thirdly, this paper discusses on the classification of masonry structure and makesan in-depth analysis of settlement cracks. And then this paper judges the actualengineering cracks based on the above analysis.Fourthly, the paper analyses stress and deformation the wall with deep beam modelby the different settlement caused by foundation pit excavation. The analysis of themasonry crack criterion has been made. An assessment model based on crack isproposed with engineering verification.Fifth, by using the fuzzy mathematics, this paper builds models of the buildingsafety evaluation and foundation pit safety risk evaluation, and puts forward the effectevaluation model of the foundation on building based on the evaluation of the buildingand foundation pit above. Taking actual project as an example, this paper tries to testand verify the model above.