波浪荷载下粉质土动应变和动强度的试验研究

Experimental study on dynamic strain and strength of silt under wave load

为寻找不同振动频率的波浪荷载作用下海底粉质土的动应变和动强度发展规律,进行了一系列的模拟不同振动频率的波浪荷载的动三轴试验.试验选用杭州湾地区分布较广的粉土,研究了振动频率的变化对粉土动应变和动强度的影响.试验结果表明,粉土的动应变和动强度的发展与土样所受的固结应力、围压、循环应力比和振动频率有关;在等向固结条件下围压对土样的累积轴向应变增长的影响作用是由波浪荷载振动频率的高低决定的;波浪荷载振动频率的改变对不同围压作用下粉土的动强度影响很大,并且在该类粉土中存在临界循环应力比.

In order to investigate the behavior of dynamic strain and dynamic strength of seafloor silt under wave load with different vibration frequency,a series of tests by using cyclic dynamic triaxial device were carried out in this paper.The silt distributing abroad in Hangzhou bay was chosen as research object to evaluate the effect of vibration frequency on dynamic strain and dynamic strength of silt.It is shown that the development of dynamic strain and dynamic strength of silt was in relation to the consolidation stress,ambient pressure,critical cycling stress ratio and vibration frequency.In the case of isotropic consolidation,the effect of ambient pressure on the increment of the cumulated axial strain was determined by the vibration frequency of wave load.The vibration frequency of wave load has considerable effect on dynamic strength of silt under different pressures.