Research On Dynamic Response For Diaphragm Wall Sheet-pile Structures Under Earthquake Motion

With simple structure, short construction period, cheap cost, good durability and good adaptability to local overloading, sheet pile wharfs are widely used in coastal and inland areas. Since the sheet pile wharfs are in sea and river bank slope area, the stress mechanism is very complex, and the current calculation theory and method of sheet pile wharfs are still in not fully mature stage, researches on sheet pile structures are mostly in static state, researches of dynamic response of sheet pile structures under seismic loads are relatively less. In recent years, earthquakes occur frequently all over the word, news about damage of building structures, property damage and human casualties are often reported, which also attracted people’s attention. With respect to building bridges and other structures, seismic design of port structures is in a relatively slow state, therefore, as one of the three port structure, researches on seismic aspects of sheet pile wharfs are significant. Based on a ground wall sheet pile practical engineering, numerical simulation method is adopted, static and dynamic characteristics of the sheet pile structure are researched by using nonlinear finite element software, while nonlinear constitutive model of soil is introduced, contact nonlinear characteristic of pile-soil is considered, reasonable two-dimensional model of finite-infinite element coupling is established, the main contents are as follows:(1) Three main theoretical calculation method of sheet pile structure are systematic summarized. Based on a ground wall sheet pile actual projects, calculated by using finite element software ABAQUS and PLAXIS 2D, compared calculation results with vertical elastic foundation beam method which is recommend by standard. The similarities and differences between the three methods are analyzed in detail, the reasonableness and accuracy of finite element model are verified. Moreover, influences of buried depth and front wall stiffness to sheet pile structure stress are emphasis studied.(2) The nonlinear characteristics of soil and pile-soil contact are considered, infinite units are used to eliminate the influence of seismic wave reflection, reasonable two-dimensional model of sheet pile wall structure is established, nonlinear dynamic response of single anchor sheet pile structure under seismic loads is studied. Variety regularity from moment of front wall, rod force, moment of anchorage wall, acceleration and Fourier spectrum of front wall and horizontal displacement are summarized. Moreover, influences of vertical motion to structural vibration are emphasis studied. On the background of previous chapter, different finite element models are established, influences of structure feature (buried depth and front wall stiffness) and grounds feature to dynamic response of sheet pile are analyzed in detail.(3) Research status of sheet pile wharf with barrier piles are summarized in detail and practical simplified calculation method is putted forward. Dynamic response regularity of this type of structure is studied, compared calculation results with single anchor sheet pile structure, blinds effect of blind piles is verified. Moreover, respect to this kind of structure, seismic reinforcement measures from ground slope and hydraulic structures are putted forward...