本文關(guān)鍵詞： 巖土參數(shù) 小樣本 置信水平 變異性 邊坡穩(wěn)定　出處：《鐵道科學(xué)與工程學(xué)報(bào)》2017年04期 　論文類型：期刊論文

【摘要】：巖土工程勘察規(guī)范統(tǒng)一使用95%保證率單側(cè)置信下限值作為土體強(qiáng)度指標(biāo)標(biāo)準(zhǔn)值,用于補(bǔ)償小樣本抽樣帶來(lái)的安全風(fēng)險(xiǎn),但在變異性較大時(shí)可能造成過(guò)盈估計(jì)。基于均值相同的小、中、大變異水平強(qiáng)度參數(shù)總體,采用固定容量的小樣本多批次隨機(jī)抽樣方法,構(gòu)建不同保證率的c和φ標(biāo)準(zhǔn)值分布空間,分析與之映射的均質(zhì)土坡安全系數(shù)結(jié)果空間的分布特征,討論等安全系數(shù)原則下參數(shù)保證率與土體變異水平的內(nèi)在關(guān)系。研究結(jié)果表明:安全系數(shù)的離散程度與土體變異性和參數(shù)置信水平均呈正相關(guān),采用95%置信水平統(tǒng)一值將導(dǎo)致對(duì)變異性較大土體的邊坡安全程度估計(jì)過(guò)低;以安全系數(shù)結(jié)果空間的分位值相等為控制條件,提出土體變異性增大可相應(yīng)降低參數(shù)置信水平的建議。
[Abstract]:In geotechnical engineering survey code, 95% guarantee rate one-sided confidence lower limit value is used as the standard value of soil strength index, which is used to compensate for the safety risk caused by small sample sampling. However, the interference estimation may be caused when the variability is high. Based on the small, medium and large variation level strength parameters of the same mean, the method of multi-batch random sampling of small samples with fixed capacity is adopted. The distribution space of c and 蠁 standard values of different guarantee rates is constructed, and the distribution characteristics of the result space of safety factor of homogeneous soil slope mapped with it are analyzed. This paper discusses the intrinsic relationship between the guarantee rate of parameters and the variation level of soil under the principle of equal safety coefficient. The results show that the dispersion degree of safety factor is positively correlated with the variability of soil and the confidence level of parameters. Using the unified value of 95% confidence level will lead to the overestimation of the slope safety degree of the high variability soil mass, and take the equal quantile value of the result space of the safety factor as the control condition. It is suggested that the increase of soil variability can reduce the confidence level of parameters.
【作者單位】： 西南交通大學(xué)土木工程學(xué)院;高速鐵路線路工程教育部重點(diǎn)實(shí)驗(yàn)室;
【基金】：國(guó)家重點(diǎn)基礎(chǔ)研究發(fā)展規(guī)劃(973計(jì)劃)項(xiàng)目(2013CB036204)
【分類號(hào)】：TU43
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本文編號(hào)：1517988