Analysis And Engineering Application Of Ultimate Bearing Capacity Of Concrete Pile-baseplate Wall Structure Anchored With Curved Column

With the development of urban construction and economy,the importance of intensive development and utilization of urban underground space is increasingly prominent.It is a new idea to use pile-wall composite structure to improve the utilization rate of underground space,but there are still few relevant engineering applications at home and abroad.Taking the section of "a city tunnel Project in the northern part of Beijing" as the background,this paper studies the ultimate bearing capacity,deformation characteristics and strength of pile-slab wall integral pull-down trench structure under service conditions.The main contents are as follows:(1)This paper studies and analyzes the connection mode and application practice of the current pile-wall structure,expounds the working mechanism of the rear anchorage reinforcement,obtains the bearing capacity calculation formula of the plane anchorage reinforcement,and analyzes the influence of material strength,anchor solid diameter,anchorage depth,and spacing of the anchorage reinforcement on the bearing capacity of the anchorage reinforcement.(2)Based on the ultimate bearing capacity analysis of the anchorage form of curved reinforcement required for pile-slab wall integral structure connection,a THREE-DIMENSIONAL finite element model of curved reinforcement of circular pile was established to simulate the pult-out failure test of cylindrical curved reinforcement.The failure characteristics and bearing capacity of curved reinforcement and planar reinforcement of circular pile were compared and studied.This paper analyzes the influence of the Angle of curved surface group reinforcement on the failure mode of circular pile concrete and its ultimate bearing capacity,and obtains the reasonable Angle of curved surface group reinforcement,which provides the basis for engineering design and construction.(3)Establish the finite element model of pile-slab wall integral pull-down groove structure with curved anchorage technology.The stress and deformation of pile-plate-wall integral pull-down groove structure and traditional pull-down groove structure under different working conditions are analyzed and compared,and the deformation characteristics and overall stress mechanism of the supporting pile under the structure are explored.Nine construction conditions,such as foundation pit excavation and pull-down trench construction,were analyzed,and the bearing capacity of pile-plate-wall monolithic structure was compared with that of traditional structure.The feasibility and advantages of pile-plate-wall monolithic pull-down trench structure were verified.(4)In view of the overall force characteristics of pile-slab wall integral puller structure with curved bar anchorage technology,the finite element analysis under anti-floating condition and temperature stress condition was carried out.The anti-floating advantages of pile-slab wall monolithic structure compared with traditional structure are analyzed by comparing the upward displacement of structure bottom plate under anti-floating condition.The stress and concrete damage of the side wall structure constrained by the anchorage of curved surface planting bars were analyzed under different limit temperature conditions,and the safety of the structure was verified under temperature conditions,and the corresponding engineering measures were put forward.