通过室内模型试验研究钙质砂中桩的承载性状,并采用石英砂进行对比。试验结果表明:在钙质砂和石英砂中桩的承载性状差异显著;开、闭口对桩的承载性能影响不大,相对密实度越大表现越明显;相同相对密实度下钙质砂中闭口桩的承载力较石英砂中低很多;钙质砂中桩侧荷载分担较小,大部分荷载由桩端土体承担,桩身下部与上部轴力相差不大,密实度越大,桩端轴力分担比例越高;石英砂中,桩身轴力沿桩身呈迅速减少,轴力衰减速率随深度增加而增大;与钙质砂相比,石英砂中桩侧摩阻力大很多;钙质砂和石英砂中桩侧摩阻力分布形式相似,近似呈抛物线型,表现出相同的性质;钙质砂中桩侧摩阻力未随相对密实度的增大而明显增加,而石英砂中桩侧摩阻力随相对密实度的增大而增加十分显著。
Abstract
The bearing behaviors of pile in calcareous soil foundation were studied by model test. Silica sand was also tested for comparison. Results reveal that the bearing behaviors of single pile in calcareous sand are different with those in silica sand. The bearing capacity of end-open pipe pile hardly differs from that of end-closed pipe pile. But in the presence of the same relative compaction, the bearing capacity of end-closed pipe pile in calcareous sand is much lower than that in silica sand. Moreover, in calcareous sand, the soil at pile’s endpoint undertakes most of the loads, and the axial force on the upper part of the pile has no big difference with that on the lower part. The greater the soil compactness, the more the ratio of load sharing by pile’s axial force. In silica sand, the axial force of pile reduces rapidly along the depth direction, and the rate of decay grows with the increase of depth. The side friction of pile in silica sand is larger than that in calcareous soils. The side friction of pile in calcareous sand distributes in a parabola shape, which is similar with that in silica sand. In calcareous sand, the side friction resistance of pile does not increase with the increase of relative compactness; whereas in silica sand, the increase is remarkable.
关键词
钙质砂 /
模型试验 /
承载力 /
桩侧摩阻力 /
颗粒破碎
Key words
calcareous sand /
model test /
bearing capacity /
side frictional resistance /
grain crushing
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 汪 稔, 宋朝景, 赵焕庭, 等. 南沙群岛珊瑚礁工程地质[M]. 北京: 科学出版社, 1997.
[2] 刘崇权, 杨志强, 汪 稔. 钙质土力学性质研究现状与进展[J]. 岩土力学, 1995, 16(4):75-83.
[3]ALBA J L,AUDIBERT J M. Pile Design in Calcareous and Carbonaceous Granular Materials, and Historic Review[C]∥Proceedings of the 2nd International Conference on Engineering for Calcareous Sediments. Bahrain, February 21-24, 1999: 29-44.
[4]NYLAND G. Detailed Engineering Geological Investigation of North Rank in a Platform Site[C]∥ Engineering for Calcareous Sediments: Proceedings of the International Conference on Calcareous Sediments, Perth, Australia, March 15-18, 1988: 503-512.
[5] RAINES R D,SICILIANO R J,HYDEN A M. Pile Driving Experience in Bass Strait Calcareous Soils[C]∥ Engineering for Calcareous Sediments: Proceedings of the International Conference on Calcareous Sediments, Perth, Australia, March 15-18, 1988: 173-181.
[6] DUTT R N ,INGRAM W B. Significance of In-situ and Laboratory Tests for Design of Foundations in Granular Carbonate Soils[C]∥Proceedings of the 23rd Annual Offshore Technology Conference in Houston. Houston, May 6-9, 1991: 155-163.
[7] 单华刚.珊瑚礁钙质土中桩基工程承载性状研究[D]. 武汉:中国科学院武汉岩土力学研究所, 2000.
[8] 江 浩.钙质砂中桩基工程承载性状研究[D]. 武汉:中国科学院武汉岩土力学研究所, 2009.
[9] 秦 月, 孟庆山, 汪 稔, 等. 钙质砂地基单桩承载特性模型试验研究[J]. 岩土力学, 2015, 36(6): 1714-1720.
[10]秦 月, 姚 婷, 汪 稔, 等. 基于颗粒破碎的钙质沉积物高压固结变形分析[J]. 岩土力学, 2014, 35(11): 3123-3128.
[11]江 浩, 汪 稔, 吕颖慧, 等. 钙质砂中模型桩的试验研究[J].岩土力学, 2010, 31(3): 780-784.
[12]江 浩, 汪 稔, 吕颖慧, 等. 钙质砂中群桩模型试验研究[J]. 岩石力学与工程学报, 2010, 29( 增1): 3023-3028.
[13]杨俊杰. 相似理论与结构模型试验[M]. 武汉: 武汉理工大学出版社, 2005.
[14]DATTA M, GULBATI S K, RAO G V. Crushing of Calcareous Sand during Shear[C]∥Proceedings of Offshore Technology Conference. Houston, April 30-May 3, 1979. DOI: http:∥dx.doi.org/10.4043/3525-MS.
基金
国家自然科学基金项目(51308209,51608192);水能资源利用关键技术湖南省重点实验室开放基金项目(PKLHD201602);湖南科技大学科研启动基金(E51497)
PDF(1481 KB)
