Research On Bearing Capacity Of The Wharf With Steel Casing Reinforced Concrete Pile Based On The Theory Digital Speckle

Digital Speckle Correlation Method is the nondestructive examination that measure the object surface deformation field depends on Optoelectronic information technology and digital image processing technology.The DSCM is the non-contact measure that takes photos of the surface of natural or man-made speckle before and after deformation the calculates and get the date of displacement stress and strain.The DSCM can be used in full court and is highly precise and simple.Since 1980 s,DSCM has been wildly used in Material engineering,Bridge engineering and medical science researchIn this paper,the DSCM used in mechanical experiment of steel pipes-reinforced concrete piles in wharf experiment.We used both traditional method and DSCM to measure the displacement of the piles under the horizontal load.By comparing results,the analysis shows that it is electronic noise and light that influence the gray scale image and cause errors.So,in this paper,it uses stable light and avoids vibrationg in order to improve the accuracy of the experiment and decrease random errors.Also,we had a model experiment on All-vertical-pile Frame Wharf,trying to find out nod mechanical characteristics when reinforced concrete piles node connected with steel rungs and reinforced concrete piles node connected with concrete are loaded.By calculating the speckle image,we get the strain nephogram of node and find that when loaded,the stress concentration was happened at welding construction area of node in wharf.The result is that there is a large stress concentration phenomenon in the welded structure area of the Wharf under the action of the load.Through the finite element software simulation,the calculation of the node parts of the stress,the comparative analysis of experimental and numerical simulation of the causes of error.Finally,the finite element software is used to simulate the welding process of the node.We chose 18 different geometric parameters nodes,get them loaded and analyze their bearing capacity.We discuss the influence of diameter-thickness ratio on distribution of residual stress,and test whether residual stress is related to bearing capacity.We come up with a method of improving welding technology to reduce the effect of welding structure‘s residual stress on wharf bearing capacity.