| 考虑桩底沉渣的灌注桩可靠度分析方法 |
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| 引用本文： | 李典庆,鄢丽丽.考虑桩底沉渣的灌注桩可靠度分析方法[J].岩土力学,2008,29(1):155-160. |
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| 作者姓名： | 李典庆 鄢丽丽 |
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| 作者单位： | 武汉大学 水资源与水电工程科学国家重点实验室，武汉 430072 |
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| 摘 要： | 基桩的完整性检测不一定都能够检测到基桩中的缺陷，这些缺陷将会影响到基桩的安全性。为此，提出了考虑基桩可能出现缺陷时的基桩可靠度分析方法。以单桩桩底可能出现的沉渣缺陷为例，采用全概率理论将完整桩的失效概率和桩底含有沉渣的桩的失效概率有机地结合起来，得到了单桩的失效概率。采用基桩承载力折减系数来定量地考虑沉渣对基桩承载力的影响，并进一步推导了桩底含沉渣的基桩承载力偏差系数和变异系数的计算公式。算例分析表明，所提方法能够定量地反映基桩中可能出现的沉渣对基桩可靠度的影响。桩底沉渣对桩的可靠指标具有明显的不利影响。随着沉渣厚度和桩的直径的增加，桩底含有沉渣的桩的可靠指标逐渐减小；桩的可靠指标随着桩长的增加逐渐增大。如果不考虑桩可能出现沉渣的质量问题，基桩的安全性将明显地被高估。基桩的完整性检测可以有效地提高基桩的安全性。
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| 关 键 词： | 灌注桩 桩底沉渣 失效概率 可靠度 桩承载力 |
| 文章编号： | 1000-7598-（2008）01-0155-06 |
| 收稿时间： | 2006-06-07 |
| 修稿时间： | 2006年6月7日 |
Reliability evaluation of bored pile considering possibility of toe debris presence |
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| LI Dian-qing,YAN Li-li.Reliability evaluation of bored pile considering possibility of toe debris presence[J].Rock and Soil Mechanics,2008,29(1):155-160. |
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| Authors: | LI Dian-qing YAN Li-li |
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| Institution: | State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China |
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| Abstract: | Defects present in a pile may not always be detected by integrity tests, which will adversely affect safety of the pile. This paper aims to propose a methodology to quantitatively evaluate the reliability of pile foundations considering the possibility of pile defects presence. Taking the toe debris present in a single pile for example, the probability of failure of the pile considering the possibility of toe debris presence is formulated by integrating the probabilities of failure for an intact pile and a pile with toe debris systematically within the framework of the total probability theory. The pile capacity reduction factor is presented to account for the effect of toe debris on the pile capacity. Moreover formulae for calculating the bias factor and coefficient of variation of the pile with toe debris are derived. The results indicate that the impact of the possibility of toe debris presence on the reliability of piles can be quantitatively evaluated using the proposed method in a rational way. The reliability of the pile is adversely affected by the presence of toe debris. The reliability index of the pile with toe debris decreases with the thickness of toe debris and the pile diameter; and it increases with the pile length. When the possibility of toe debris presence is not taken into account, the safety of the pile is highly overestimated. The reliability of piles can be highly improved with the implementation of pile integrity tests. |
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| Keywords: | bored piles toe debris probability of failure reliability pile capacity |
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