考虑冲刷影响的筒型基础竖向极限承载力研究
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摘要
大直径宽浅式筒型基础,阻水宽度大,在位工作期间受波浪海流作用,其周围土体易被冲刷。为研究单侧地基土体受冲刷后筒型基础的竖向极限承载力变化,通过引进冲刷率的概念,采用有限元方法研究了不同冲刷率下筒型基础的竖向极限承载力;并基于Meyerhof理论建立了计算不同冲刷率下筒型基础竖向极限承载力的极限平衡方法。研究结果表明,随着冲刷率增大,筒型基础的极限承载力出现不同程度的下降,当冲刷率为0.8时,即筒型基础单侧土体冲刷深度达6.4 m时,筒型基础的竖向极限承载力折减率为3.28%。建立的极限平衡算法可准确计算冲刷条件下筒型基础的竖向极限承载力。
The large-diameter wide-shallow bucket foundation has a large water-blocking width,and is subjected to wave and current during the working period,and the surrounding soil can be easily scoured. In order to study the vertical ultimate bearing capacity change of the unilateral foundation soil after scouring,the vertical ultimate bearing capacity of the bucket foundation under different scouring ratios was studied by introducing the concept of scouring ratio and based on the finite element method. Based on the theory of Meyerhof,the limit equilibrium method for calculating the vertical ultimate bearing capacity of the bucket foundation under different scouring ratios is proposed. The calculated results can be consistent with the finite element results,and the errors are controlled within6%. The results also show that as the scouring ratio increases,the ultimate bearing capacity of the bucket foundation decreases to a different extent. When the scouring ratio is 0.8,that is,the scoured depth of the single-sided soil on the bucket foundation is 6.4 m,the vertical ultimate bearing capacity of the bucket foundation reduction rate is 3.28%.
The large-diameter wide-shallow bucket foundation has a large water-blocking width,and is subjected to wave and current during the working period,and the surrounding soil can be easily scoured. In order to study the vertical ultimate bearing capacity change of the unilateral foundation soil after scouring,the vertical ultimate bearing capacity of the bucket foundation under different scouring ratios was studied by introducing the concept of scouring ratio and based on the finite element method. Based on the theory of Meyerhof,the limit equilibrium method for calculating the vertical ultimate bearing capacity of the bucket foundation under different scouring ratios is proposed. The calculated results can be consistent with the finite element results,and the errors are controlled within6%. The results also show that as the scouring ratio increases,the ultimate bearing capacity of the bucket foundation decreases to a different extent. When the scouring ratio is 0.8,that is,the scoured depth of the single-sided soil on the bucket foundation is 6.4 m,the vertical ultimate bearing capacity of the bucket foundation reduction rate is 3.28%.
引文
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[13]刘梅梅.海上风机复合筒型基础承载力及优化设计研究[D].天津:天津大学,2014.(LIU Meimei. Bearing capacity and optimization design of composite foundation for offshore wind turbine[D]. Tianjin:Tianjin University,2014.(in Chinese))
[14]李全辉.河道冲刷对既有桥梁单桩基础竖向承载性状影响的数值分析[D].天津:天津大学,2014.(LI Quanhui.Numerical analyses of the influences of scour on the vertical bearing behavior of single pile foundations for bridges[D]. Tianjin:Tianjin University,2014.(in Chinese))
[15]李驰,王建华,刘振纹.软土地基单桶基础循环承载力研究[J].岩土工程学报,2005,27(9):1040-1044.(LI Chi,WANG Jianhua,LIU Zhenwen. Cyclic bearing capacity of single bucket foundation on soft clay strata[J]. Chinese Journal of Geotechnical Engineering,2005,27(9):1040-1044.(in Chinese))
[16]东南大学,等.土力学.第3版[M].北京:中国建筑工业出版社,2010.(Southeast University,et al. Soil Mechanics.3rd edition[M]. Beijing:China Architecture&Building Press,2010.(in Chinese))
[17]胡卫东.临坡地基破坏模式及极限承载力确定方法研究[D].长沙:湖南大学,2016.(HU Weidong. Study on the failure mode and bearing capacity determination method of ground foundation adjacent to slope[D]. Changsha:Hunan University,2016.(in Chinese))
[18]楼晓明,朱克宏,朱亚娟.圆形基础的临界荷载和形状系数[J].同济大学学报(自然科学版),2012,40(1):33-37.(LOU Xiaoming,ZHU Kehong,ZHU Yajuan. Critical load and shape factors of circular foundations[J]. Journal of Tongji University,Natural Science,2012,40(1):33-37.(in Chinese))
[2]史忠强.海上风电复合筒型基础周围局部冲刷研究[D].天津:天津大学,2013.(SHI Zhongqiang. Study on local scour around composite bucket foundation of offshore wind turbines[D]. Tianjin:Tianjin University,2013.(in Chinese))
[3]于通顺,练继建,齐越,等.复合筒型风电基础单向流局部冲刷试验研究[J].岩土力学,2015,36(4):1015-1020.(YU Tongshun,LIAN Jijian,QI Yue,et al. Experimental study of the local scour around the composite bucket foundations of wind turbines under unidirectional current[J]. Rock and Soil Mechanics,2015,36(4):1015-1020.(in Chinese))
[4]蒋杏雨.宽浅式筒型基础在粉质粘土中的承载力研究[D].天津:天津大学,2016.(JIANG Xingyu. Analysis on bearing capacity of wide and shallow bucket foundation in silty clay[D]. Tianjin:Tianjin University,2016.(in Chinese))
[5]乐丛欢.筒型基础动静荷载下承载力研究[D].天津:天津大学,2006.(LE Conghuan. Study on bearing capacity of bucket foundation under the static and dynamic[D]. Tianjin:Tianjin University,2006.(in Chinese))
[6]闫澍旺,霍知亮,孙立强,等.海上风电机组筒型基础工作及承载特性研究[J].岩土力学,2013(7):2036-2042.(YAN Shuwang,HUO Zhiliang,SUN Liqiang,et al. Study of working mechanism and bearing capacity behavior of bucket foundation for offshore wind turbine[J]. Rock and Soil Mechanics,2013(7):2036-2042.(in Chinese))
[7]贾素华.筒型基础承载力研究[D].天津:天津大学,2006.(JIA Suhua. The study on bearing capacity of bucket foundation[D]. Tianjin:Tianjin University,2006.(in Chinese))
[8]刘润,陈广思.砂土中带裙板防沉板基础坚向承载力的上限解[J].海洋工程,2015,33(4):45-52.(LIU Run,CHEN Guangsi. Upper bound solutions of vertical bearing capacity of skirted mudmat in sand[J]. The Ocean Engineering,2015,33(4):45-52.(in Chinese))
[9]丁红岩,翟少华,张浦阳.海上风电大尺度顶承式筒型基础承载力特性有限元分析[J].工程力学,2013,30(6):124-132.(DING Hongyan,ZHAI Shaohua,ZHANG Puyang. Finite element analysis of bearing capacity behavior of cover-load bearing large-scale bucket foundation for offshore wind turbines[J]. Engineering Mechanics,2013,30(6):124-132.(in Chinese))
[10]丁红岩,胡彩清,张浦阳,等.桩—筒组合基础在单层黏土中水平承载性能分析[J].海洋工程,2014,32(2):30-37.(DING Hongyan,HU Caiqing,ZHANG Puyang,et al. Analysis of horizontal bearing capacity performance of pile-bucket foundation for offshore wind turbines in single-layer clay[J]. The Ocean Engineering,2014,32(2):30-37.(in Chinese))
[11]刘梅梅,练继建,杨敏.宽浅式筒型基础竖向承载力研究[J].岩土工程学报,2015,37(2):379-384.(LIU Meimei,LIAN Jijian,YANG Min. Vertical bearing capacity of wide-shallow bucket foundation[J]. Chinese Journal of Geotechnical Engineering,2015,37(2):379-384.(in Chinese))
[12]刘梅梅.海上风电宽浅式筒型基础失效模式及承载力研究[D].天津:天津大学,2011.(LIU Meimei. A study on failure mode and bearing capacity of offshore wind power bucket foundation with wide and shallow dimension[D]. Tianjin:Tianjin University,2011.(in Chinese))
[13]刘梅梅.海上风机复合筒型基础承载力及优化设计研究[D].天津:天津大学,2014.(LIU Meimei. Bearing capacity and optimization design of composite foundation for offshore wind turbine[D]. Tianjin:Tianjin University,2014.(in Chinese))
[14]李全辉.河道冲刷对既有桥梁单桩基础竖向承载性状影响的数值分析[D].天津:天津大学,2014.(LI Quanhui.Numerical analyses of the influences of scour on the vertical bearing behavior of single pile foundations for bridges[D]. Tianjin:Tianjin University,2014.(in Chinese))
[15]李驰,王建华,刘振纹.软土地基单桶基础循环承载力研究[J].岩土工程学报,2005,27(9):1040-1044.(LI Chi,WANG Jianhua,LIU Zhenwen. Cyclic bearing capacity of single bucket foundation on soft clay strata[J]. Chinese Journal of Geotechnical Engineering,2005,27(9):1040-1044.(in Chinese))
[16]东南大学,等.土力学.第3版[M].北京:中国建筑工业出版社,2010.(Southeast University,et al. Soil Mechanics.3rd edition[M]. Beijing:China Architecture&Building Press,2010.(in Chinese))
[17]胡卫东.临坡地基破坏模式及极限承载力确定方法研究[D].长沙:湖南大学,2016.(HU Weidong. Study on the failure mode and bearing capacity determination method of ground foundation adjacent to slope[D]. Changsha:Hunan University,2016.(in Chinese))
[18]楼晓明,朱克宏,朱亚娟.圆形基础的临界荷载和形状系数[J].同济大学学报(自然科学版),2012,40(1):33-37.(LOU Xiaoming,ZHU Kehong,ZHU Yajuan. Critical load and shape factors of circular foundations[J]. Journal of Tongji University,Natural Science,2012,40(1):33-37.(in Chinese))