Stress Charactersistics Of Steel Casing Rock-socketed Pile And Contact Supports Joints In Inland Overhead Vertical Wharf

Steel casings rock-socketed pile framework wharf as a new wharf structure type is widely used in inland port terminal construction.The wharf framework setting two layer of horizontal and vertical support,the upper layer is vertical and horizontal reinforced concrete support,while the lower is vertical and horizontal steel supports.Stress state of the framework pier wharf structure joints act as a control role when the wharf is in a complex stress condition,but research on joints of the framework wharf structure is very rare.In this paper,joints stress characteristics were studied through large scale model test and numerical simulation method based on the twelfth Five-Year plan of the National Science & Technology Pillar Program about Key technologies Research on port construction in canalized mountain rivers.The main research work and achievements are as follows.Firstly,the test scheme is developed rely on the wharf structure overall model.In order to obtain the distribution of shear stress and strain of components under different load,104 measuring points and 7 kinds of impact force loading conditions are setted.Secondly,stress and strain of the steel casings rock-socketed pile and contact supports joints are analyzed based on the model test.The shear stress of member cross-section in steel casings rock-socketed pile and steel contacet supports joints under the impact force in descending order is steel horizon support,steel vertical support and steel casing.In terms to steel casings rock-socketed pile and reinforced concret contacets support joints,the order is steel casing,column,reinforced concret horizon support and reinforced concret vertical support.The impact force transmitted between each node along the path presented a decreasing trend through analyzing the strain of steel horizon support.Thirdly,the effect on each joint member,pile and the bent are investigated by analyzing the strain curves under different impact while the water level changes.For steel casings rock-socketed pile and steel contacet supports anti-L type joint,the strain of steel horizon support increased while the water level drops,the strain of steel vertical support decreased while the water level turns lower.For steel casings rock-socketed pile and steel contacet supports L type joint,the strain of steel horizon support decreased while the water level drops,and water level changes have less affect on strain of steel vertical support.There is a mutation on the strain of steel casing where the joint isformed,and the point of impact force get closer to the joint the mutant became more obvious.Maximum strain pile will change under the impact force,pile of the last row arise maximum strain at high water level hit,and pile of the front row arise maximum strain at low water level hit.Finally,Reasonable material constitutive relations and steel-reinforced concrete core pile casing contacting relationship are chosen to build partial joint finite element model to propose structure optimization program.For steel casings rock-socketed pile and steel contacet supports anti-L type joint,oblique bracing could be set at the lower side between steel contacts support and steel casing.For steel casings rock-socketed pile and steel contacet supports L type joint,taking steel casing get into the reinforced concrete contact supports 10 mm as optimization program.