Long-term Deformation And Stability For The Slope Of Open Type Wharf On Piles Considering The Creepage Characteristics Of Soft Clay

In recent years,many structure safety problems of large differences in structure deformation due to the creep deformation of the soil of the wharf slope were found in coastal areas of our country,which eventually led to the occurrence of cracking damage to its important components.In addition,the creepage characteristics of bank soil will not only make the deformation of wharf-bank system more complicated,but also will lead to the slope soil strength gradually decay with time.At the present stage,most researches related to creep of soil on wharf bank are mostly based on the analysis of the effect of soil creep on the deformation characteristics of wharf bank slope,and the time dependent characteristics of shear strength parameters of wharf bank slope caused by it are not considered.Therefore,it is necessary to study the effect of soil creep on the strength of the slope and to analyze the time-variant stability of the slope of the open type wharf on piles.In this paper,the creep deformation characteristics of the open type wharf on piles are analyzed firstly,and then the attenuation effect of soil shear strength caused by creep of soft soil is considered.The long-term strength model of soft soil is established.Time-variant reliability algorithm of the slope is put forward to quantitatively evaluate the time-varying stability of slope of wharfs.The specific research work of this paper is as follows:1.A three dimensional elastic-plastic finite element model of pile-foundation soil interaction is established.The simulation method of pile-soil contact was established and the analysis flow of creep calculation was put forward.The influence of soft soil creep on the deformation characteristics of the bank slope of the wharf as well as the deformation and stress characteristics of the wharf is analyzed.2.Creep characteristics of bank slope soil will not only make the deformation characteristics of the bank more complex,but also will lead to soil strength gradually decayed over time.Therefore,in this paper,the influence of soil creep on shear strength is considered,and the criterion of long-term strength failure of soil is analyzed.Based on the Singh-Mitchell creep model,the long-term strength model of soft soil on bank slope is established to quantitatively evaluate the variation of soil shear strength parameters with time due to soil creep.3.Combining the time-dependent reliability theory and the finite element batch method for stability of bank slope,a time-dependent reliability assessment method is proposed for the open type wharf on piles considering the time-variant characteristics of shear strength index.The traditional Monte Carlo random sampling method is optimized by using Latin hypercube sampling technique and the safety factor of the bank slope is solved by finite element analysis based on the strength reduction method.By writing finite element batch program,the interface framework of bank slope reliability analysis and general finite element software is established.Based on the proposed algorithm,the time-varying reliability of the wharf slope is quantitatively evaluated.The time-variant law of bank stability is discussed.The variation of the shear strength index and the reliability of the soil of the bank slope are analyzed influences.