Dragging ball test on flow characteristics of liquefied silt under wave loading
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摘要: 粉质土大量存在于黄河水下三角洲地区,粉土液化过程中具有类似流体的性质,可以把液化过程中的粉土视为黏性流体进行研究。基于流体力学中Stokes黏滞阻力原理,在波浪水槽试验基础上,设计了一套测量液化过程中粉土流变特性的拖球装置,并对其实用性进行验证。在铺设有粉土底床的波浪水槽中埋入可以水平滑动的小球,通过拖动小球在粉土中水平运动,测量小球所受阻力值的大小,用以计算液化粉土表观动力黏度。充分考虑试验中波浪要素、超孔压比等因素的影响。结果表明,该装置能够满足试验要求;波浪循环荷载作用下,观察到了孔压的累积至液化的过程;波浪参数对结果有较大影响,其中波高越大,表观黏度值越小;同一波高情况下,表观黏度随时间缓慢增加;随着超孔压比的升高,波浪作用下粉土表观黏度值逐渐减小。Abstract: Silty seabed exists widely in the Yellow River Subaqueous Delta. Liquefied silt has properties similar to fluid. It has found that the behavior of liquefied silt can be simulated appropriately by modeling the liquefied silt as viscous fluid. According to the theory of Stokes Law,the test apparatus of flow characteristics of liquefied silt is developed based on the wave flume tests. A steel sphere,embedded in the wave flume,can be moved in the horizontal direction when the silt liquefaction occurs. Resistance force and velocity of the steel sphere are measured during sphere dragging,then apparent viscosity can be evaluated. Considering fully the infection of wave parameters and excess pore pressure ratio in the tests. The results indicate that this apparatus can meet the test requirements. It can be observed the processes of pressure buildup when it is forced by the cyclic loading of wave. Wave parameters have great influence on the results,apparent viscosity decreased as wave height increase. Apparent viscosity slowly enlarge with the passing of time at the same wave heights. Along with the increasing of pore pressure ratio,the apparent viscosity of the liquefied silt apparently decreases.
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Key words:
- silt /
- liquefaction /
- fluid /
- dragging ball test
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Prior D B,Suhayda J N,Lu N Z,et al. Storm wave reactivation of a submarine landslide[J]. Nature,1989,341(7):47-50. 刘涛,冯秀丽. 黄河水下三角洲低角度斜坡失稳模式探讨[C]//渤海湾油气田勘探开发技术论文集. 北京:中国石化出版社,2010(7):72-78. Liu Tao,Feng Xiuli. Slope failure mode of low angle on Yellow River Delta[C]//Bohai Bay Oil and Gas Field Exploration and Development Technology Proceedings. Beijing:China Petrochemical Press,2010(7):72-78. 刘汉龙,周云东,高玉峰. 砂土地震液化后大变形特性试验研究[J]. 岩土工程学报,2002,24(2):142-146. Liu Hanlong,Zhou Yundong,Gao Yufeng. Study on the behavior of large ground displacement of sand due to seismic liquefaction[J]. Chinese Journal of Geotechnical Engineering,2002,24(2):142-146. Sasaki Y,Towhata I,Tokida K I,et al. Mechanism of permanent displacement of ground caused by seismic liquefaction[J]. Soils and Foundations,1992,32(3):79-96. Towhata I,Vargas-monge W,Orense R P,et al. Shaking table tests on subgrade reaction of pipe embedded in sandy liquefied subsoil[J]. Soil Dynamics and Earthquake Engineering,1999,18(5):347-361. Nishimura S,Towhata I,Honda T. Laboratory sheartests on viscous nature of liquefied sand[J]. Soils and Foundations,2002,42(4):89-98. 陈育民,刘汉龙,周云东. 液化及液化后砂土的流动特性分析[J]. 岩土工程学报,2006,28(9):1139-1143. Chen Yumin,Liu Hanlong,Zhou Yundong. Analysis on flow characteristics of liquefied and post-liquefied sand[J]. Chinese Journal of Geotechnical Engineering,2006,28(9):1139-1143. Hwang J I,Kim C Y,Chung C K,et al. Viscous fluid characteristics of liquefied soils and behavior of piles subjected to flow of liquefied soils[J]. Soil Dynamics and Earthquake Engineering,2006,26(2):313-323. Miyajima M,Kitaura M,Koike T,et al. Experimental study on characteristics of liquefied ground flow[C]//The First International Conference on Earthquake Geotechnical Engineering. Rotterdam:A A Balkema Publishers,1995:969-974. 刘汉龙,陈育民. 砂土液化后流动特性分析[C]//第一届全国岩土本构理论研讨会论文集. 北京:北京航空航天大学出版社,2008. Liu Hanlong,Chen Yumin. Analysis on flow characteristics of dynamic tests on post liquefied sand[C]//Symposium of the First National Geomaterial Seminar. Beijing:Beihang University Press,2008. 刘晓瑜. 黄河三角洲埕岛海域波浪作用下液化分区[D]. 青岛:中国海洋大学,2007. Liu Xiaoyu. Liquefaction zone devision of silty strata in Chengdao Sea area,Huanghe delta with wave load[D]. Qingdao:Ocean University of China,2007. 王立忠,潘冬子,潘存鸿,等. 波浪对海床作用的试验研究[J]. 土木工程学报,2007,40(9):101-109. Wang Lizhong,Pan Dongzi,Pan Cunhong,et al. Experimental investigation on wave-induced response of seabed[J]. China Civil Engineering Journal,2007,40(9):101-109. 杨琳,蒋学炼,李炎保. 波浪引起的海床失稳机理及有关孔隙水压力的讨论[J]. 海洋技术,2004,23(4):75-80. Yang Lin,Jiang Xuelian,Li Yanbao. Seabed instability mechanism and discuss the wave-induced pore water pressure[J]. Ocean Technology,2004,23(4):75-80. 张民生,刘红军,李晓东,等. 波浪作用下黄河口粉土液化与"铁板砂"形成机制的模拟试验研究[J]. 岩土力学,2009,30(11):3347-4456. Zhang Minsheng,Liu Hongjun,Li Xiaodong,et al. Study of liquefaction of silty soil and mechanism of development of hard layer under wave actions at Yellow River Estuary[J]. Rock and Soil Mechanics,2009,30(11):3347-4456. 刘茜,郑西来,刘红军. 黄河三角洲粉土液化的试验研究[J]. 世界地震工程,2007,23(2):161-166. Liu Qian,Zheng Xilai,Liu Hongjun. Experimental studies on liquefaction behavior of silt in the Yellow River delta[J]. World Earthquake Engineering,2007,23(2):161-166.
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