摘要
在黄河口潮坪上选择典型研究区,进行了模拟波浪荷载的现场振动试验,利用轻型静力触探仪测记振动前、振动刚刚结束以及静置一段时间后土体贯入阻力的强度值,研究了海床土强度的丧失、恢复过程及影响因素。研究结果发现:模拟波浪荷载振动导致土体强度丧失发生在海底面下一定深度范围内,强度丧失量和恢复量沿深度呈抛物线型变化。振动后,土体表面排出的水和细粒物质环绕振动点周围形成一系列微型“泥火山”。振动导致土强度最大恢复量值与强度最大丧失量值出现在同一深度处;振动结束 2 h 后,土体强度超过振动前原状土体强度,振动使土体强度丧失与恢复受土体曾经历的水动力作用强弱、振动前土体的原始强度、振动荷载的循环次数、振动能量大小、土体的深度、静置的时间等因素的影响显著。黄河口海床土体强度独特变化规律的成因机理有待进一步研究。
To simulate the sea bed strength's loss and recovery due to the wave load, we chose typical study areas on the tidal flat of the Yellow River Mouth, and carried out in-situ impactive vibration test. We got the silt's penetration value before and just after the vibration, also the silt's penetration value after several periods of time. Using these penetration values, we have done some research on the procedure and influential factors of silt strength's loss and recovery. From the research, we found that the strength loss caused by vibration occurs at certain depth under the sea bed, and the variation of silt strength's loss and recovery appears like a parabola along the depth. After the vibration, water and fine object appear at the surface layer of the silt, and a series of minimal mud volcanoes come into being around the vibration site. The silt's maximum strength recovery appears at the same depth as the maximum loss. After three-hour recovery, the silt strength surpassed the silt strength before the vibration. The following factors remarkably affect the silt strength's loss and recovery, the hydrodynamic action that the silt had experienced, the silt's original strength, circular times of vibration load, the vibration energy, the silt depth and the time of recovery, etc. The mechanism of silt's strength variation due to vibration and recovery is very special and further study of the mechanism is required.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2005年第3期351-358,共8页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.40172088)
山东省自然科学基金资助项目(No.Q99E10)
国家重点规划项目(973)(No.2002CB412400)
关键词
黄河口粉土
强度丧失与恢复
现场振动试验
Hydrodynamics
Mechanical properties
Silt
Vibration measurement
Water wave effects
