李书兆, 李亚, 鲁晓兵. 桩基贯入过程中土体大变形分析与流动机理研究[J]. 工程力学, 2017, 34(6): 157-165. DOI: 10.6052/j.issn.1000-4750.2016.01.0018
引用本文: 李书兆, 李亚, 鲁晓兵. 桩基贯入过程中土体大变形分析与流动机理研究[J]. 工程力学, 2017, 34(6): 157-165. DOI: 10.6052/j.issn.1000-4750.2016.01.0018
LI Shu-zhao, LI Ya, LU Xiao-bing. LARGE DEFORMATION ANALYSIS AND FLOW MECHANISM STUDY OF THE SOIL DURING PILE PENETRATION[J]. Engineering Mechanics, 2017, 34(6): 157-165. DOI: 10.6052/j.issn.1000-4750.2016.01.0018
Citation: LI Shu-zhao, LI Ya, LU Xiao-bing. LARGE DEFORMATION ANALYSIS AND FLOW MECHANISM STUDY OF THE SOIL DURING PILE PENETRATION[J]. Engineering Mechanics, 2017, 34(6): 157-165. DOI: 10.6052/j.issn.1000-4750.2016.01.0018

桩基贯入过程中土体大变形分析与流动机理研究

LARGE DEFORMATION ANALYSIS AND FLOW MECHANISM STUDY OF THE SOIL DURING PILE PENETRATION

  • 摘要: 土体大变形问题是海洋岩土工程界研究的难点,由于其变形梯度较大、流动机理复杂等特点,常规的岩土工程分析方法在求解该问题时表现出明显的局限性。因此,该文研究了求解土体大变形问题的解析方法,即Strain Path Method (SPM)和Shallow Strain Path Method (SSPM),详细介绍了这两种方法的计算原理;并基于大、小应变理论,采用SSPM分析了理想土性条件下桩基础贯入过程中周围土体的流动机理和位移场变化规律;最后,将SPM和SSPM计算结果进行比较分析,阐明了两者之间的内在关系。基于大应变理论,采用SSPM计算得到的土体位移场与Sagaseta给出的结果具有较好的一致性,验证了计算结果的准确性。研究结果显示桩端上部土体会发生隆起现象,而桩端附近及底部土体具有下沉的位移,且在贯入深度位置处,土体下沉位移达到最大值。在径向位置r/R=3(距桩壁1倍直径)处,基于大、小应变理论计算结果具有较好的一致性。研究成果有助于了解土体的大变形特性,也可为数值计算结果的校验提供基本数据。

     

    Abstract: Large deformation of soil mass is a challenge in marine geotechnical engineering. Conventional geotechnical engineering analysis methods are limited to large deformation issues on account of complexity of flow mechanics and high gradient of deformation. The analytical methods solving the large soil deformation issues, Strain Path Method (SPM) and Shallow Strain Path Method (SSPM), are studied in the paper. The paper presents the calculated theory, analyzes the change rule and flowing mechanism of soil displacement field induced by pile penetration based on large and small strain theory under ideal soil conditions. Finally, the comprasions of calculation resultes by SPM and SSPM clarify the internal relation of both methods. Results show that the soil deformation field determined by using SSPM based on the large strain theory agrees well with that given by Sagaseta, which illustrates the validity of the calculated results. The soil upheaval occurs on the upper of the pile tip, but the soil moves downward in the vicinity and bottom of the pile tip. The settlement reaches the maximum value when the vertical position is equal to the depth of pile penetration. Calculating results based on the large and small strain theory are generally consistent when the radial position lies in the 3 times pile radius which is 1 times pile diameter away from the pile edge. Research findings in the paper help elucidate the large soil deformation behavior in a consistent and rational manner, and also provide the basic data for validating numerical simulations.

     

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