Stability Analysis Of Soft Foundation Sluice Structure Based On Three-Dimensional Numerical Simulation

Sluice engineering is the basis of optimal allocation of water resources,and plays an important role in irrigation water supply and water resources utilization.The sluice built on the soft foundation is prone to large compression deformation and even local plastic failure due to the large compressibility,low bearing capacity and poor stability of the soft soil foundation under the self weight and external load of the sluice chamber,which will seriously affect the operation of the sluice.The traditional theoretical calculation method is relatively simple,but the boundary conditions and load treatment are greatly simplified,so it is difficult to reflect the overall role of the structure,and can not reflect the stability and safety of the whole process of sluice construction.For engineering practice,the three-dimensional numerical simulation analysis method should be used for calculation,the interaction between the structure and the foundation should be fully considered,and the whole sluice structure and the foundation should be analyzed as a whole.In this paper,a reconstruction project of the Yellow River diversion sluice is taken as an example.Through the collection of sluice engineering data and hydrogeological investigation,the engineering geological conditions of the sluice are reasonably analyzed and evaluated,and the applicability and effectiveness of the sluice foundation treatment measures are analyzed.A numerical model is established by using the finite difference software to simulate the whole construction process of the sluice.By solving the displacement and deformation in the construction project,The safety of the whole construction process of soft foundation sluice is evaluated to provide basis for on-site construction.The specific research results are as follows:(1)A three-dimensional numerical simulation method is proposed to analyze the safety and stability of sluice construction on soft foundation.Compared with the traditional theoretical calculation method,the three-dimensional numerical simulation method can more clearly and intuitively show the various stress and strain changes on the soft foundation sluice,and can overcome the shortcoming that the traditional theoretical calculation can not reflect the displacement and stress changes of the overall structure of the sluice.In addition,this paper takes a reconstruction project of the Yellow River diversion gate as an example to establish a numerical model for the whole construction process of the Yellow River diversion gate.By analyzing the change characteristics of the stress field and displacement field during the construction process of the gate,the applicability of the adopted foundation treatment method in the soft foundation sluice is verified,which can provide a reference for the construction safety evaluation of the soft foundation sluice in the future.(2)The stability analysis of sluice before and after the foundation treatment measures is carried out.The calculation shows that the stability of sluice without foundation treatment measures can not meet the requirements,and foundation treatment is required;The stability of the sluice after foundation treatment meets the requirements of the specification.According to the stability calculation of sluice chamber and culvert and the calculation of foundation bearing capacity,in order to ensure that the anti sliding stability of sluice chamber of Yellow River Diversion Sluice with foundation treatment measures does not meet the specification requirements,the allowable bearing capacity of sluice chamber bearing layer and underlying layer is less than the foundation stress,the allowable bearing capacity of culvert body bearing layer and underlying layer from section II to Section VI is less than the foundation stress,and the allowable bearing capacity of culvert body bearing layer from Section VII to Section VIII is less than the foundation stress,Therefore,foundation treatment measures shall be taken.Therefore,in combination with the foundation conditions of the gate site and the stability requirements of the gate chamber,the foundation of the first section of culvert is reinforced by high-pressure jet grouting,and the foundation of the tunnel body is reinforced by cement soil mixing piles.According to the theoretical calculation,after the foundation treatment,the stability of the sluice and the bearing capacity of the foundation can meet the specification requirements;The settlement of composite foundation is 3.5 ～ 13.8cm,less than the allowable settlement value of 15 cm,and the settlement difference between adjacent structures is less than 5cm,meeting the requirements.(3)The numerical simulation and stability analysis of the sluice after foundation treatment are carried out.The simulation results show that the sluice stability meets the requirements,and there will be no safety problems during the construction process.Based on the actual geological exploration data of the Yellow River Diversion Sluice,a finite difference model is established to simulate the construction process of the soft foundation sluice and analyze its stability.The simulation results show that the maximum tensile stress of the upstream wing wall structure is 0.4 MPa,the maximum tensile stress of the bottom plate is0.6 MPa,and the maximum settlement is 5 cm,all of which meet the specification requirements;The maximum tensile stress of the downstream wing wall structure is about 0.3MPa,the maximum compressive stress of the bottom plate is 0.5 MPa,and the maximum settlement is 3 cm,all of which meet the specification requirements;The maximum tensile stress of the gate chamber structure is 0.28 MPa,the maximum compressive stress of the gate bottom plate is 0.75 mpa,and the maximum settlement is 2.7 cm,all of which meet the specification requirements;The maximum tensile stress of culvert structure is 0.025 MPa,the maximum compressive stress of culvert bottom plate is 0.018 MPa,and the maximum settlement is 2.4 cm,all of which meet the specification requirements.It can be seen that the deformation and stress of each component of the sluice during the simulated construction meet the requirements of the specification.