Experimental Research On The Shear Property Of Interfacial Bonding Of Concrete And Stone

It has a long history for stone arch bridge.It has been used very commonly in our country.As the time goes on,some defects appared in these bridges,such as low bearing capacity and aging structure,which can't meet the needs of traffic development.Therefore,it is of great significance to study the reinforcement theory and method of stone arch bridge to ensure traffic safety.The concrete enlarged section method is widely used in the reinforcement of stone arch bridges.It can effectively increase the stress section of the main arch ring and improve the structural bearing capacity.There are many engineering examples.However,there is still a lack of necessary experimental and theoretical research on the complex mechanical behavior of the composite structure formed by new concrete and old stone arch ring.In this dissertation,the theoretical and experimental research work on the shear performance of concrete-stone bonding interface is carried out.The main research contents are as follows:(1)Two specimens of Z-type and hoop-type were designed,and the mechanical test of shear performance of concrete-stone bonding interface was carried out.The stress process,crack initiation and failure process of concrete and stone interface were studied.The shear strength of the two specimens was compared.The influencing factors and influence mechanism of shear strength were analyzed according to the test results.(2)According to the test results and the microstructure characteristics of concrete and stone,a "double-interface three-zone-three-layer" bond model for concrete and stone interfaces is established.The model is used to analyze the bonding mechanism,shear mechanism and interface bond-slip performance,and a solution method for the interface bond-slip relationship in the case of mixed failure under the condition of planted is proposed.(3)Using the finite element analysis method,the frictional contact interface model with viscous behavior is selected,and the finite element analysis model of the test specimen is established.The nonlinear calculation analysis is carried out by loading mode and boundary conditions in the test.The results show that the finite element results agree well with the experimental results,and the difference is less than 7%.Through analysis,the whole process of loading of specimens from loading to failure parts and force transfer mechanism of interface loadwas is deeply understood.Finally,the influence of the thickness of hoop layer and the size of the test piece on the interfacial shear strength is discussed.(4)Based on the experimental results and finite element calculation result,the shear capacity calculation model of concrete-stone interface is established.The formulas for calculating the shear strength of the interface considering the increasing effect of hoop action are presented.The calculated results and the experimental results agree well,the difference is less than 10%.Furthermore,a method for calculating the shear strength of interface shear strength in engineering is proposed.(5)Combined with the example of maintenance and reinforcement of a stone arch bridge,the application of concrete-stone interface shear performance theory in bridge repair and reinforcement was studied.Applying the research results of this paper,the shear strength of the concrete-stone bonding interface in the actual bridge span structure is calculated.The results show that the interface between concrete and stone is well combined and the shear strength meets the requirements.By using the program of plane bridge,the whole bridge structure after reinforcement is analyzed and calculated,which indicates that the bridge is repaired and strengthened by the method of increasing section of concrete,and the reinforcement effect is good,and the expected effect is achieved.