| 大直径超长桩打桩过程中桩周土体的疲劳与强度恢复 |
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| 引用本文： | 刘润,闫澍旺.大直径超长桩打桩过程中桩周土体的疲劳与强度恢复[J].岩土力学,2009,30(2):452-456. |
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| 作者姓名： | 刘润 闫澍旺 |
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| 作者单位： | 天津大学,建筑工程学院,天津,300072 |
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| 基金项目： | 国家高技术研究发展计划(863计划)，国家自然科学基金 |
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| 摘 要： | 大直径超长桩的出现给海上的打桩施工增加了难度和复杂性，也使得打桩分析和预估锤击数具有重要的意义。研究表明，当连续进行打桩施工时，桩长时间连续运动导致桩侧土体强度降低，土体产生了疲劳，沉桩相对容易，使得桩体的贯入度与锤击数较预测偏低；当施工停止一段时间后，土体固结排水，强度得到恢复甚至提高，导致继续打桩时难度增加，锤击数增高或出现无法继续贯入的现象。结合一维应力波动理论、桩-土相互作用模型、土体的有效应力原理和固结理论，提出了模拟土体疲劳和强度恢复的数值分析方法，对采油平台的桩基工程进行了打桩分析，计算结果与实测数据吻合较好，说明提出的数值模拟方法具有可靠性。
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| 关 键 词： | 打桩分析 波动理论 土体疲劳 强度恢复 |
| 收稿时间： | 2007-05-15 |
Research on soil fatigue and restoration during deep penetration large diameter pile driving |
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| LIU Run,YAN Shu-wang.Research on soil fatigue and restoration during deep penetration large diameter pile driving[J].Rock and Soil Mechanics,2009,30(2):452-456. |
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| Authors: | LIU Run YAN Shu-wang |
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| Institution: | School of Civil Engineering, Tianjin University, Tianjin 300072, China |
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| Abstract: | Since deep penetration large diameter steel pipe piles have been widely used in platform foundation, pile drivability analysis and blow count prediction play an important role in pipe driving. Research results show that during driving pile by a hammer, the continuous impacts will cause reduction of the strength of the soil around the pile and make the pile penetration easier. This phenomenon is called the fatigue effect. The soil strength fatigue leads to the prediction blow counts are always more than the data. However, it is all known that much more blows are needed in the subsequence driving process. The soil consolidation and strength restoration make the subsequence driving difficult. In order to explain the phenomenon, the mechanism of soil fatigue and restoration is analyzed based on the consolidation theory in soil mechanics. A program has been established based on the one dimensional wave equation, pile and soil interaction model and soil consolidation theory, which consider the soil fatigue effect and strength restoration in pile driving analysis. By simulating the practical pile driving records of blow account versus penetration of several cases, the advantages of the model are identified. The calculation results show that the model of quadratic distribution with penetration can better simulate the pile driving records. And the proposal method to estimate the ratio of the excess pore water pressure converting to effective stress is reliable. |
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| Keywords: | drivability analysis wave theory soil fatigue strength restoration |
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