【作者】 许国辉；

【导师】 刘德辅； 岳中琦；

【作者基本信息】 中国海洋大学 ， 港口、海岸与近海工程， 2006， 博士

【摘要】 在粉质土缓坡海底上,出现塌陷凹坑、土体滑动、粉砂流等工程地质灾害,而在这样的粉质土海岸,人类又有活跃的工程活动,比如黄河三角洲的石油平台建设、海底电缆管线铺设等,因此波致粉质土缓坡海底滑动的研究,对海洋生产的防灾控灾具有重要意义,基于此开展了本论文研究工作。本论文以粉质土缓坡海底为研究对象,根据海底地质调查获得的缓坡海底浅表塌陷凹坑等工程地质灾害问题,确定以波浪作用导致的粉质土缓坡海底滑动为研究目标,并以黄河水下三角洲粉质土海底作为研究实例,利用水槽试验、动三轴试验、现场调查测试试验、理论分析与计算、以及对前人研究成果的归纳总结等方法,展开研究工作。论文研究利用水槽试验手段,观察得到缓坡海底滑动过程,表现为浅表局部软弱土体在波浪波峰波谷的剪切作用下发生成层运动并向深处发展的滑动;利用模拟波浪作用的动三轴试验,得到粉质土在循环荷载作用下强度弱化,强度指标减小的规律,强度降低后的粉质土在波浪剪切作用下能够发生滑动,从而解释了粉质土缓坡海底滑动的机制;利用黄河三角洲潮滩现场的测试试验工作说明了粉质土海底发生滑动等工程地质灾害分布的差异性;利用理论分析给出了波致粉质土缓坡海底滑动的计算方法,并计算得到在波浪作用下粉质土强度弱化后,黄河水下三角洲缓坡海底能够发生滑动;利用多维联合概率采用重点抽样法给出波浪导致海底滑动概率研究的随机模拟方法;基于海底粉质土在大的波浪作用下可以发生强度弱化、指标降低,对粉质土海岸开敞航道在风暴浪作用期间的骤淤问题,提出风暴浪状况下的航道淤积模式为“悬移质+推移质+层移质+泥沙流滑+航道侧面土体滑坡”。更多还原

【Abstract】 In the gentle-slope silty seabed there are various engineering geological hazards such as collapse pits, slope failure, silt flows, as well as intense human activities such as construction of oil rigs and pipe installation of submarine cables in the Yellow River Delta. Therefore, research in seabed landslide on gentle-slope silty seabed is of great significance in the prevention and control of hazards, and on such basis the research work in this paper is carried out.Seabed of gentle silty slope is specifically investigated in this paper. On the basis of data obtained in submarine geological investigation of superficial collapse pits on gentle-slope seabed, wave-induced landslide of such gentle-slope silty seabed is taken as the study objective, and the silty seabed of the Yellow River Delta is taken as a study case. Research work includes flume experiments, dynamic triaxial experiments, in-situ investigation and measurement or experiments, theoretical analysis and calculation, and summing up of previous research results.In this paper, flume experiments are carried out to observe the sliding course of gentle-slope seabed, which exhibits as local superficial soil body, acted upon by the shearing actions of wave peak and wave trough, sliding downwards to form sheet flow. Dynamic triaxial tests are carried out to stimulate wave actions, results of which show that strength of silty soil is weakened under actions of cyclic loads and as a result of reduction of strength indexes the weakened silty soil tends to slide under the shearing actions of waves; this could reasonably explain the sliding mechanism of gentle-slope silty seabed. Results of in-situ measurement and experiments indicate the distribution discrepancy of engineering geological hazards such as landslide in silty seabed. In theoretical analysis, methods are given to calculate wave-induced landslide of gentle-slope silty seabed, which shows that after strength of silty soil is weakened landslide tends to occur in the gentle-slope seabed of the Delta. On the basis of更多还原