荷载频率对土体动强度影响分析

Analysis of loading frequency on dynamic strength of soil

基于目前开展的受不同频率波浪荷载作用的土体动强度研究较少,而我国的港口岸线土质大多为粘性土和粉土,根据波浪荷载的特点,文章对不同类别的土样分别进行了不同振动频率的固结不排水动三轴剪切试验。试验表明,加荷频率对土体动强度有一定影响,而影响程度还受到土性条件的制约。通过试验得出,振动频率对粉质粘土和粉土的动强度有一定影响,在0.05~1.0 Hz范围内是单调增加;荷载频率对粉砂的动强度也有影响,但不是单调增加或递减,f=0.2 Hz时,动强度最高,f=0.5~1.0 Hz时,粉砂动强度变化不大。

At present, little research has been done on the dynamic strength of soil that bears different frequen-cy wave loads, and there are mostly clayey soil and silt in Chinese port shoreline. According to the characteristics ofwave load, the method of consolidated undrained dynamic triaxial test was designed. When soil of the retaining wallfoundation was under different frequency of dynamic loads, the effects of different soils dynamic strength were stud-ied. Experiments show that the loading frequency has a certain influence on the soil strength, and the influence is af-fected by soil conditions. Some conclusions drew through tests are that vibration frequency has certain effect on dy-namic strength of silty clay and silty soil. In the 0.05~1.0 Hz range, the dynamic strength increases. There are ef-fects of loading frequency on dynamic strength of silty sand, but it is not monotonically increasing or decreasing. Dy-namic strength of silty sand is highest when loading frequency equals to 0.2 Hz, and when the load frequency is inthe 0.5 Hz to 1.0 Hz range, the dynamic strength of silt changes little.