成层土中桩土耦合扭转振动特性理论研究-地震工程与工程振动.PDF

29 5 Vo.l 29 No. 5 2009 10 JOURNAL OF EARTHQUAKE ENGINEER ING AND ENG INEERING V IBRATION Oct. 2009 : 1000- 1301( 2009) 05- 0138- 09 胡昌斌, 张涛 (, 350108) : , , , , , , , , , ; , , , , , , : ; ; ; : P315985 : A Torsional vibration of pile in layered soils w ith considering soi-l pile in teraction HU Changb in, ZHANG T ao ( Co llege of Civ ilEng ineering, FuzhouU niversity, Fuzhou 350108, China) Abs tract: Considering the interaction bewt een visco-elastic layered soils and integral pile, the dynam ic response at the pile head to an arb itrary dynam ic load is theoretically investigated. By Laplace transforms and the transm it prop- erty of mi pedance function, the analytical expression of the mi pedance function and disp lacement and velocity re- sponse function at the pile head in frequency dom ain and in tmi e dom ain are derived. The characteristic of interac- tion betw een soil layers and p ile is theoretically investigated. The results indicate that dynam ic characteristics of up- per layer soil are major factors that affect the comp lex stiffness of pile. P ile stiffness increases and damping decrea- sesw ith increasing modulus of upper soil. Because of the change of soilmodu lus, adm ittance curves of pile have cycle characteristicsw hich have big peak and sm all peak. When the modu lus of upper soil is h igher than that of low er layer soil, the reflectionw ave shape in tmi e domain at soild ivision surface and in itial pulses are on the contra- ry. Conversely, they are the sam e. In genaral, reflection w ave shape in tmi e domain at soil d ivision surface is flat and the amp litude is not very large. K ey w ord s: layered s