| In recent years,with the continuous increase of per capita GDP,people’s pursuit of quality of life is getting higher and higher.However,the usable land area in a lot is limited,and a large number of high-rise buildings have sprung up to effectively utilize the ground space,and there is still a broad development space for the development and utilization of underground space.In some large and medium-sized cities,for improving the living environment and building functional requirements,there have been new infrastructure as well as some tall buildings emerging,these new buildings around generally exist a large number of historical buildings and underground pipeline,such as complicated construction conditions,surrounding environment threat level is high,in construction process to ensure the safety of neighboring buildings is very important.Especially for some landmark buildings,the whole process of excavation should be carefully protected.Many experts and scholars have made great contributions to the field of deep foundation pit engineering.However,first of all,foundation pit engineering itself has strong regional characteristics,and secondly,there are many deficiencies in these studies.On the basis of previous studies,the author took a deep foundation pit project with neighboring buildings in Changsha city as an example,analyzed the simplified numerical model of the foundation pit project by using FLAC3D finite difference software,and compared the simulation results with the actual monitoring data to verify the rationality of the numerical model.Then on the basis of the model,the relationship between foundation pit excavation and adjacent buildings is analyzed by changing related parameters by controlling variables.The mutual influence between foundation pit excavation and building was analyzed from the angles of building parameters,supporting parameters and excavation scheme,and the following conclusions were drawn:(1)The interaction of building structure,support form and foundation will significantly change the curve shape of surface settlement trough outside the pit;Especially in the main settlement affected area there are independent foundation buildings easy to produce differential settlement,it is necessary to consider the joint influence of buildings,supporting structure and foundation,which may underestimate the differential settlement of buildings caused by foundation pit excavation and cause potential safety risks.(2)Reasonable pile-anchor design can effectively limit ground deformation,and foundation pit excavation has little influence on the safety and normal use of existing buildings.However,it should be noted that the selection of prestress value of anchor rod should not be too large or too small,otherwise it will cause insufficient anchorage strength or uneven settlement and tilt of buildings.(3)From the perspective of deformation control,it is more beneficial to reduce deformation and reduce the risk of foundation pit engineering for asymmetric foundation pit excavation with adjacent shallow foundation frame structure.(4)In practical engineering,the adjacent building weight has a significant influence on the deformation of supporting structure and the surface settlement,the relation between the building weight and the horizontal displacement of pile and the surface settlement is exponential.At the same time,the increased weight of the building will cause the building to tilt more. |
