考虑上覆水综合作用的水下真空预压沉降分析
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摘要
上覆水问题是水下真空预压与陆上真空预压的一大不同点。在水下真空预压中,上覆水会对地基固结和沉降产生一定的影响。通过有限元模拟研究了上覆水对加固区土体的沉降所产生的两方面影响,即荷载作用方面和边界渗透方面。基于有限元结果,结合固结理论和渗流理论,提出一种考虑上覆水综合作用效果的地基沉降计算方法,并通过一则案例分析对该方法进行了验证,同时与传统计算方法进行了对比分析。结果显示,与传统方法相比所得结果与实测数据更加吻合,说明了考虑上覆水对地基沉降的综合影响是可靠的。最后对工程实际中的应用提出了一定的建议。
Covering water is one of the factors that make the underwater vacuum preloading different from the onshore one. It affects the behaviors of consolidation and settlement of the foundation to some degree. FEM analysis is adopted to investigate the loading and the boundary seepage effects of the covering water on the foundation settlement. An analysis method is proposed with the theories of consolidation and seepage to consider the combined effect of the covering water on the settlement on the basis of the FEM results, which is proved to be reasonable and valid with a case study. Comparison is also made between the conventional and the proposed methods. The research results show that the prediction by the proposed method is better in fitting with the measured data than the conventional one, suggesting the reasonability and validity of the proposed method in considering the effect of the covering water. Advices are also given to the application of the method in engineering practice.
Covering water is one of the factors that make the underwater vacuum preloading different from the onshore one. It affects the behaviors of consolidation and settlement of the foundation to some degree. FEM analysis is adopted to investigate the loading and the boundary seepage effects of the covering water on the foundation settlement. An analysis method is proposed with the theories of consolidation and seepage to consider the combined effect of the covering water on the settlement on the basis of the FEM results, which is proved to be reasonable and valid with a case study. Comparison is also made between the conventional and the proposed methods. The research results show that the prediction by the proposed method is better in fitting with the measured data than the conventional one, suggesting the reasonability and validity of the proposed method in considering the effect of the covering water. Advices are also given to the application of the method in engineering practice.
引文
[1]张敬,刘爱民.水下真空预压的加固机理分析[J].岩土工程学报,2007,29(5):644-649.(ZHANG Jing,LIUAi-min.Analysis of mechanism of consolidation of soil improved with underwater vacuum preloading method[J].Chinese Journal of Geotechnical Engineering,2007,29(5):644-649.(in Chinese))
[2]张敬.水下真空预压中真空产生机制、预压加固机理及其应用技术研究[D].天津:天津大学,2007.(ZHANG Jing.Research on the vacuumization method,treatment mechanism and application technology of underwater vacuum preloading[D].Tianjin:Tianjin University,2007.(in Chinese))
[3]HU L.Consolidation behavior of soft soil subjected to on-land and underwater vacuum preloading[D].Hong Kong:The Hong Kong University of Science and Technology,2010.
[4]闫澍旺,李亚奇,林澍,等.泥封法水下真空预压室内模型试验及数值模拟[J].中国港湾建设,2017,37(9):5-10.(YAN Shu-wang,LI Ya-qi,LIN Shu,et al.Indoor model experimental research and numerical simulation of underwater vacuum preloading with clay-sealing method[J].China Harbour Engineering,2017,37(9):5-10.(in Chinese))
[5]刘润,闫澍旺,苗中海,等.水下真空预压中真空产生机制的研究[J].中国港湾建设,2003(5):29-35.(LIU Run,YAN Shu-wang,MIAO Zhong-hai,et al.Study of mechanism of vacuumization in underwater vacuum preloading[J].China Harbour Engineering,2003(5):29-35.(in Chinese))
[6]KARLSRUD K,GREGERSEN O,NERLAND?,et al.Vacuum consolidation of seabed clay-A full scale experiment[C]//Proceedings of the 14th European Conference on Soil Mechanics and Geotechnical Engineering.Madrid,2007:1335-1340.
[7]韩雪峰,邝国麟,谭国焕,等.水下真空预压过程中孔隙水压力变化规律研究[J].岩土工程学报,2008,30(5):658-662.(HAN Xue-feng,KWONG A K L,THAM L G,et al.Variation law of pore water pressure in soil improved by underwater vacuum preloading method[J].Chinese Journal of Geotechnical Engineering,2008,30(5):658-662.(in Chinese))
[8]刘爱民.变动水压荷载对真空预压加固效果的影响[J].地震工程学报,2015,2:467-471.(LIU Ai-min.Influence of varied water pressure loading on strengthening effect of vacuum preloading[J].China Earthquake Engineering Journal,2015,2:467-471.(in Chinese))
[9]CHU J,GUO W.Land reclamation using clay slurry or in deep water:challenges and solutions[J].Japanese Geotechnical Society Special Publication,2016,51(2):1790-1793.
[10]王传成.水下真空预压的机理研究[D].天津:天津大学,2005.(WANG Chuan-cheng.Study of mechanism of underwater vacuum preloading[D].Tianjin:Tianjin University,2005.(in Chinese))
[11]GOURVENEC S M,WHITE D J.Elastic solutions for consolidation around seabed pipelines[C]//Proceedings of the Annual Offshore Technology Conference.Houston,2010.
[2]张敬.水下真空预压中真空产生机制、预压加固机理及其应用技术研究[D].天津:天津大学,2007.(ZHANG Jing.Research on the vacuumization method,treatment mechanism and application technology of underwater vacuum preloading[D].Tianjin:Tianjin University,2007.(in Chinese))
[3]HU L.Consolidation behavior of soft soil subjected to on-land and underwater vacuum preloading[D].Hong Kong:The Hong Kong University of Science and Technology,2010.
[4]闫澍旺,李亚奇,林澍,等.泥封法水下真空预压室内模型试验及数值模拟[J].中国港湾建设,2017,37(9):5-10.(YAN Shu-wang,LI Ya-qi,LIN Shu,et al.Indoor model experimental research and numerical simulation of underwater vacuum preloading with clay-sealing method[J].China Harbour Engineering,2017,37(9):5-10.(in Chinese))
[5]刘润,闫澍旺,苗中海,等.水下真空预压中真空产生机制的研究[J].中国港湾建设,2003(5):29-35.(LIU Run,YAN Shu-wang,MIAO Zhong-hai,et al.Study of mechanism of vacuumization in underwater vacuum preloading[J].China Harbour Engineering,2003(5):29-35.(in Chinese))
[6]KARLSRUD K,GREGERSEN O,NERLAND?,et al.Vacuum consolidation of seabed clay-A full scale experiment[C]//Proceedings of the 14th European Conference on Soil Mechanics and Geotechnical Engineering.Madrid,2007:1335-1340.
[7]韩雪峰,邝国麟,谭国焕,等.水下真空预压过程中孔隙水压力变化规律研究[J].岩土工程学报,2008,30(5):658-662.(HAN Xue-feng,KWONG A K L,THAM L G,et al.Variation law of pore water pressure in soil improved by underwater vacuum preloading method[J].Chinese Journal of Geotechnical Engineering,2008,30(5):658-662.(in Chinese))
[8]刘爱民.变动水压荷载对真空预压加固效果的影响[J].地震工程学报,2015,2:467-471.(LIU Ai-min.Influence of varied water pressure loading on strengthening effect of vacuum preloading[J].China Earthquake Engineering Journal,2015,2:467-471.(in Chinese))
[9]CHU J,GUO W.Land reclamation using clay slurry or in deep water:challenges and solutions[J].Japanese Geotechnical Society Special Publication,2016,51(2):1790-1793.
[10]王传成.水下真空预压的机理研究[D].天津:天津大学,2005.(WANG Chuan-cheng.Study of mechanism of underwater vacuum preloading[D].Tianjin:Tianjin University,2005.(in Chinese))
[11]GOURVENEC S M,WHITE D J.Elastic solutions for consolidation around seabed pipelines[C]//Proceedings of the Annual Offshore Technology Conference.Houston,2010.