CAJ | 학술논문

　　考虑土体材料的黏性阻尼和桩-土扭转耦合振动，把桩看作一维杆，将土体视作三维轴对称黏弹性介质，对黏弹性地基中现浇混凝土大直径管桩（简称 PCC桩）扭转振动频域特性进行了理论研究，采用 Laplace 变换和分离变量的方法求得了桩顶扭转频域响应解析解。将所得解完全退化到实心桩的解，并与经典平面应变解进行对比，验证了解析解的合理性。分析了桩长以及土体黏性阻尼系数对桩顶速度导纳和复动刚度的影响，得到了各参数对桩扭转振动特性影响的规律。分析表明：桩周土黏性阻尼系数增大可以显著提高桩顶扭转复动刚度和减小速度导纳振荡幅值，而桩芯土黏性阻尼系数的影响不明显；桩长越长，桩顶复动刚度越大，速度导纳振荡幅值越小，但当桩长增大到一定程度时，再继续增加桩长，桩顶复动刚度基本没有改变。
　　고필토체재료적점성조니화장-토뉴전우합진동，파장간작일유간，장토체시작삼유축대칭점탄성개질，대점탄성지기중현요혼응토대직경관장（간칭 PCC장）뉴전진동빈역특성진행료이론연구，채용 Laplace 변환화분리변량적방법구득료장정뉴전빈역향응해석해。장소득해완전퇴화도실심장적해，병여경전평면응변해진행대비，험증료해석해적합이성。분석료장장이급토체점성조니계수대장정속도도납화복동강도적영향，득도료각삼수대장뉴전진동특성영향적규률。분석표명：장주토점성조니계수증대가이현저제고장정뉴전복동강도화감소속도도납진탕폭치，이장심토점성조니계수적영향불명현；장장월장，장정복동강도월대，속도도납진탕폭치월소，단당장장증대도일정정도시，재계속증가장장，장정복동강도기본몰유개변。
Considering the viscous damping of the soil and the soil-pile torsional coupled vibration, regarding the pile as a one-dimensional rod and the soil as three dimensional axisymmetric viscoelastic medium, the frequency-domain torsional vibration response of cast-in-place concrete large-diameter pipe pile (PCC pile)in viscoelastic soil is theoretically investigated. The analytical solution in frequency domain is obtained by Laplace transformation method and the method of separation of variables. The solution is compared with the solution of a solid pile and plane strain solution extended to pipe pile to verify its rationality. Moreover, by analyzing the effects of pile length and viscous damping coefficient of soil on the velocity admittance and complex dynamic stiffness, the regularity of variations of the torsional vibration characteristics with parameters is obtained. Analysis shows that the complex dynamic stiffness at the top of pile increases with the increase of viscous damping coefficient of outer soil and the oscillation amplitudes of the velocity admittance decrease; while the effect of viscous damping of inner soil on the complex dynamic stiffness and velocity admittance is little. The complex dynamic stiffness increases and the oscillation amplitudes of the velocity admittance decrease with the increase of the pile length. However, when the pile length increases to a critical length, the effect trends to vanish.