Numerical Analysis And Experimental Study On Forming Mechanism And Preventive Measures Of Cracks In Transmission Tower Foundation Columns

The foundation pillar plays a vital role in the entire transmission structure.It connects the upper structure and the lower foundation.Once the pillar fails,it will affect the normal operation of the entire transmission tower.The bearing capacity and cracks under uniform load have been considered in the design of the foundation column.However,due to construction and installation errors in the actual project,the flange and the concrete did not make sufficient contact,thus causing excessive local pressure and cracking of foundation columns.In this paper,the actual engineering transmission structure foundation is taken as the research object.Numerical simulation and experimental research are carried out from the bearing capacity of the base column and damage cracking.The main research contents and results are as follows:(1)The damage development law of the foundation column was explored by using damage simulation calculation technology,and the cracking mechanism of the foundation column was revealed.The simulation results show that the load is mainly concentrated at the bottom of the steel pipe under compression,which results in large compressive stress and deformation in the concrete area at the bottom of the steel pipe.The existence of deformation causes large tensile stress and strain at the concrete outside the bottom of the steel pipe.When the tensile strain exceeds the limit tensile strain of the concrete,cracks in the concrete beyond the bottom of the steel tube will begin to occur;under tensile conditions,the load mainly acts on the anchor bolts,and the load is extremely unevenly distributed along the anchor bolts.The top of the hole is cracked and develops outwards.(2)Aiming at the reinforcement mesh reinforcement measures,the effects of different mesh spacings,different mesh reinforcement diameters,and different mesh layout heights on the tensile and compression bearing capacity and damage of concrete were studied,and comprehensive considerations were made from concrete specifications,economics,and construction.80mm pitch is selected as the optimal mesh layout interval,diameter 14mm is the optimal mesh reinforcement diameter,and the outer diameter of the steel pipe with the height of the bottom mesh layer being 2 times the concrete surface height is used as the optimal mesh layout height.(3)The tensile and compression tests of ordinary concrete and mesh-embedded concrete were carried out.Under compression conditions,the conventional concrete was compared with the mesh-embedded concrete in terms of bearing capacity.The results show that the mesh's compressive bearing capacity is has seen an increase.Through one test and repeated loading tests,it was found that the implanted mesh can effectively prevent cracking;under tensile conditions,the concrete bearing capacity of conventional concrete and implanted mesh is compared,and the results show that the implanted mesh can improve the concrete to some extent Anti-pull load capacity.