Numerical Simulation Analysis Of Structured Mechanical For The Gravity Type U-shaped High Abutment

Due to advantages of convenient for construction and materials, gravity type U-shaped abutment is widely used in engineering.The height of the u-shaped abutment of the current standard drawing is under8meters, width within12meters, which is difficult to meet the requirements of the practical design.According to a survey based on the existing and under construction abutment,it has a mass of cracking phenomenon and the integrity was damaged when fill height is greater than8meters or width than15meters of the abutment. Through the finite element analysis simulation and field engineering test,this article studied the high fill Gravity type U-shaped abutment body strain-stress law that with different height, different width,different side wall length,different inner walls slope and different working conditions, to seek high Gravity type U-shaped abutment force characteristic, put forward the design method that makes the high abutment to prevent or alleviate crack disease and makes structure is more stable. Specific research contents and results are as follows:①Analyed the existing high Gravity type u-shaped abutment cracking phenomena in the process of construction and operation, summarize its reason which based on the analysis of a large number of information collection.Concluded the cracking reason is mainly:first, the cross section width of high abutment side wall and front wall is difficult to meet the specification requirements, there is big limitation in the current specification. Second, the active earth pressure calculation is simplified to plane calculation, which cannot really reflect the influence of the lateral earth pressure on wall body.②Analyzed the stress-strain distribution law and its change with height increasing. On the abutment body vertical compressive stress was small under large distribution, and increases with height, compressive stress increases as a whole. The maximum compressive stress appears in the front, side wall heel.Transverse stress distribution pull down on the side wall at the top of the free end as the tensile stress concentration area. The abutment is relatively stable when it’s tall, abutment under load of the table top wall aspect ratio close to1, and the thin tensile stress is large,and is easy to damage, which should be considered in the design or reinforcement.③Analyzed the stress-strain distribution under different length of side wall,which mainly affects the side wall transverse stress distribution. When the side wall length is too small, abutment is filling with smaller volume, and more difficult to maintain stability; long wall on the top is easily excessivly cracking because of the transverse tensile stress. Front, side wall junction is tensile stress concentration area, which is the weak position of disease.④Analyzed the stress-strain distribution rule under different width, narrow high abutment filling is small, filling weight is difficult to maintain the abutment stability; large number of filled soil made wide abutment’s side and front wall produce large horizontal pressure, resulting in wall body deformation. Increasing the front wall to the side wall at the upper part of the width of the transverse tensile deformation to mitigation, but also make the front wall of the tensile zone and transverse tensile stress increases, it can be seen that the front wall width mainly affecting the anterior wall of transverse stress distribution, influence on the side wall wall significantly than before.⑤Analyzed the stress-strain distribution under different inner walls slope.The table body of transverse stress increases with increasing slope, on the backfill filling stage, stress gap produced by the changes of slope is obvious; but on the operational phase which is not obvious.⑥Analyzed the abutment body’s stress-strain distribution.under different working conditions The vertical condition on the table body and the distribution of transverse stress has obvious effect, especially on the front wall of the vertical distribution of the stress and the lateral wall of lateral stress.As the main bearing structure, the front wall of gravity abutment is under vertical pressure, should pay attention to the eccentric of the center gravity and occurring topple under pressure in the design and construction process. Especially when abutment has narrow high form, need to ensure the filling in the abutment is enough in order to maintain body balance. In the operation, the greater the height of the abutment is, the longer are the side walls, bottom and front wall acting on the free end of the sidewall restriction effect is smaller, which deform increasingly intensified, for the above conclusions construction that should pay attention in the construction.⑦Confirm the simulation of the stress-strain distribution law to the tests at the construction project,.