郝斌　赵玉成　刘珍岩　李占岭　卢二岩

摘要：为研究海上风电桩基在波浪荷载作用下，产生水平向循环荷载对桩基周围土体动力特性的影响，以唐山地区滨海软土为研究对象，通过室内动三轴试验，研究不同围压、动应力幅值和振动次数条件下对软土水平向动力特性的影响。结果表明：软土水平向动强度随围压增加而增加，随振动次数增加而减小；动应力幅值增大，破坏振次减小；水平向动应变εd随振动次数增加变大，且动应力幅值越大，增速越明显，变化规律遵循Monismith模型；动应力幅值改变时，软土水平向动模量变化明显，当围压减小，动弹性模量减小；曹妃甸软土水平向间具有明显的结构性，不同围压条件下，随动应力幅值增加动阻尼比均表现增大趋势。

关键词：滨海软土；循环荷载；水平向动力特性；动三轴试验

中图分类号：TU411.8

文献标志码：A文章编号：16744764（2016）01011606

Abstract：

A series of dynamic triaxle test on soft soil in Tangshan Binhai area was carried out to understand the horizontal dynamic characteristics of the soil around the offshore wind power pile foundation under wave load. The influence of confining pressure， dynamic stress amplitude and vibration frequency on horizontal dynamic characteristics of soft soil were studied. The results show that the horizontal dynamic strength of soft soil increases with the increase of confining pressure increases，and decreases with the increase of vibration. When the dynamic stress amplitude increases， the vibration times decreases. The horizontal dynamic strain εd increases with the increase of vibration frequency， and the larger the dynamic stress amplitude is， the more significant the growth is. The change agrees well with that of the Monismith model. The change of the horizontal dynamic modulus of soft soil is significantly influenced by the dynamic stress amplitude. When confining pressure decreases， dynamic modulus decreases. The Caofeidian soft soil has distinct structural horizontal dynamic characteristics. Under different confining pressures， the damping ratio shows an increasing trend when dynamic stress amplitude increases.

Keywords：coastal soft soil； cyclic loading； horizontal dynamic characteristics； dynamic triaxial test

风电产业迅速发展，受陆地条件制约，地广人稀的海岸滩涂和海上风电产业得到重视，海上风电场建设步入发展的快车道，但沿海地区广泛分布着工程性质较差的软土。风电设施建成后桩基周围土体受到常见的动力循环荷载——波浪荷载[1]长期作用，在波浪荷载作用下土体产生的累积变形、强度及稳定性问题成为众多学者关注的重点[2]。波浪荷载作为一种作用时间长、振动较为规则的循环荷载，需考虑循环效应对桩基周围土体动力特性的影响。应用GDS室内动三轴试验系统研究波浪荷载作用下软土水平向的动力特性。……