| 黏土强度指标的测定和选取 |
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| 引用本文： | 胡海军,魏丽敏,冷伍明.黏土强度指标的测定和选取[J].岩土力学,2007,28(12):2698-2704. |
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| 作者姓名： | 胡海军 魏丽敏 冷伍明 |
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| 作者单位： | 中南大学,土木建筑学院、长沙,410075 |
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| 摘 要： | 在岩土工程界,强度指标的测定和选取存在着不统一的现象。具体表现在(1)强度试验的划分;(2)不排水强度的测试;(3)加载工程强度指标的选取;(4)卸载工程强度指标的选取。针对上述问题,指出不固结不排水试验宜称为天然固结不排水。讨论和比较了国内外常用的地基天然强度测试方法。对国内的改进有效应力法和有效固结应力法进行了理论分析,指出二者均低估了现场固结不排水强度。建立了采用各向等压固结试验模拟现场K0固结时的等效围压计算公式及等效于CK0U试验的有效固结应力法强度增长公式。分析了国外的不排水有效应力法、QRS法和不排水强度分析法的特点和适用条件,指出不排水强度分析法所采用的SHANSEP试验方法能合理考虑分期施工过程中地基土的强度增长,适合在国内采用并对国内常用的加载-卸载-加载方式获取卸载强度指标的适用情况做了分析。
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| 关 键 词： | 抗剪强度 改进有效应力法 有效固结应力法 SHANSEP试验 |
| 文章编号： | 1000-7598-（2007）12-2698-07 |
| 收稿时间： | 2005-11-18 |
| 修稿时间： | 2006-07-26 |
Determination and choice of strength index of clay |
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| HU Hai-jun,WEI Li-min,LENG Wu-ming.Determination and choice of strength index of clay[J].Rock and Soil Mechanics,2007,28(12):2698-2704. |
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| Authors: | HU Hai-jun WEI Li-min LENG Wu-ming |
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| Institution: | School of Civil and Architectural Engineering, Central South University, Changsha 410075, China |
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| Abstract: | There exists disunity, even wrong phenomenon in geotechnical community when determining and choosing strength index. The detailed several aspects are shown as follows: (1) the classification of strength test; (2) the measurement of undrained strength; (3) the strength index determination and choice for loading project; (4) the strength index determination and choice for unloading project. In above mentioned several aspects, it’s pointed out that unconsolidated-undrained test is fit to be named “natural consolidated-undrained test”. All kinds of methods measuring natural foundation soil strength are discussed and compared. Theoretical analysis of modified effective stress method and effective consolidation stress method created by Chinese scientists is made; and the results indicate that both methods conservatively estimate in-situ strength. The correspondent confining pressure formula of isotopic consolidation to model K0 consolidated state and the strength increase formula by effective consolidation stress method adopting CIU strength index equivalent to CK0U strength index are derived. The “undrained” effective stress analysis, QRS method, undrained strength analysis method are introduced. It’s pointed out that SHANSEP method adopted by undrained strength analysis can well model strength increase of foundation soil during construction stage and is fit for China to adopt. The application occasions of loading -unloading - loading way to get the unloading strength index commonly used in China are analyzed. |
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| Keywords: | shear strength modified effective stress method effective consolidation stress method SHANSEP method |
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