Finite Element Analysis Of Pile Foundation Treatment And Lock Chamber Structure Of Soft Ground Sluice Gate

Due to low bearing capacity of the foundation,the sluice gates built on soft ground may have excessive uneven settlement,which may even endanger the safety of the project.In the treatment of sluice soft soil foundation,the composite foundation formed by pile reinforcement has the advantages of high stability,fast construction and easy control,which makes it widely used.However,the selection of pile parameters in the treatment of composite foundation piles strengthened by piles is mostly based on engineering experience,without considering the interaction between pile,soil and sluice chamber structure.Only the upper load is used to select pile parameters,which may exaggerate the role of piles and cause engineering safety.Therefore,it is of great engineering significance to study the bearing characteristics and the joint action of pilesoil and lock chamber structure under different pile parameters when treating the pile foundation of sluice gates in soft soil foundation.Taking an open sluice gate as the research object and with the help of threedimensional finite element analysis software ABAQUS,the sluice gate base plate and group pile model,a joint sluice gate chamber with three holes model and the overall of pile foundation model are established.Based on the above model,the load-bearing characteristics law with different pile foundation treatment and the stress-strain law of the gate chamber structure under different working conditions are researched.The main work of this paper is as follows:(1)Relevant research literature at home and abroad has been consulted,The theory of composite foundation,foundation treatment technology and the current situation of pile soil superstructure interaction are understood,and the bearing capacity and settlement calculation of pile-soil composite foundation and the calculation method of gate chamber structure are analyzed and studied.(2)The three-dimensional models of sluice floor,cushion and pile group foundation are established,and the vertical bearing characteristics under different pile types,pile diameters,pile lengths and pile spacing are analyzed.The research results shows that: Under the action of load,due to the difference of pile modulus,the cement mixing pile shows the compression of pile body;Because of the large rigidity of precast pile,it is manifested in the penetration of pile end bearing layer.According to the geological conditions of the sluice studied in this paper,for the sluice composite foundation strengthened by cement mixing piles,increasing the pile diameter and pile length within a certain range can effectively improve the bearing capacity,but the effect of increasing the pile diameter and pile length after the pile diameter is greater than600 mm and the pile length is greater than 8m is no longer significant.When the pile spacing is greater than 2d,the role of the pile will be weakened due to the low replacement rate and the excessive compression of the pile body.Therefore,the flexible pile should be arranged in a short and dense manner.(3)The above pile foundation treatment scheme is adopted,the overall model of three hole one connection sluice chamber structure and pile soil foundation is established,and the foundation settlement,pile group displacement and stress of sluice chamber structure under four working conditions are analyzed and studied.The results show that the maximum settlement and the maximum settlement difference of the sluice reinforced by cement mixing pile meet the requirements of the specification,and the whole structure of the sluice chamber keeps healthy operation.(4)The composite modulus method is used,and the soil layer within the pile length is assumed to be homogeneous composite soil,the three-dimensional finite element analysis of the sluice under four working conditions is carried out,and compared with the sluice strengthened by original cement mixing pile.The results show that there is little difference in the stress of sluice structure under the two methods,but there is a large difference in the settlement of sluice foundation soil.Therefore,when using the composite modulus method to calculate the settlement of sluice foundation soil,the modulus of composite soil layer should be reasonably determined.