Experimental Study On Ladder-type Variable Cross-section Pile In Clay Stratum

Since the 20 th century,a large number of high-rise,large-span bridges and other buildings to build,to meet the above-mentioned structure of the large span,high-level,heavy load and different complex geological conditions,pile foundation has been widely used.In order to improve the bearing capacity of the bridge foundation,the previous practice is to increase the pile length and pile diameter accordingly,thus greatly improving the project cost.Therefore,on the basis of ensuring safety,the optimization of pile foundation is very important to the construction of the project.In this engineering background,many domestic and foreign scholars and technical staff of the pile foundation(especially the shape of the pile optimization)for more in-depth study.In the efforts of many scholars,more and more new piles were studied and developed,ladder-type variable cross-section pile is one of them.In the project proved that the ladder-type variable cross-section pile with more reasonable force,the cost is more economical and other advantages.However,there are few theoretical studies on ladder-type variable cross-section piles and do not form a perfect system.Based on the previous research results,this paper uses the method of field test and numerical simulation to analyze the bearing characteristics of stepped variable cross-section piles.First of all,this paper introduces the origin of the subject,the research background,the purpose and significance of the study and the existing problems of the step-type variable cross-section pile.Secondly,the axial force transmission mechanism,the side friction resistance distribution,the pile end resistance and the load-displacement curve of the stepped variable cross-section pile and the diameter pile are analyzed and compared by the static load test of single pile.The finite element software ABAQUS is used to simulate the bearing behavior of stepped variable cross-section piles and diameter piles.The results of the simulation and the results of the test are confirmed,and the vertical bearing mechanism of the stepped variable cross-section pile is further studied.