高填方下覆结构性黄土次固结特性研究
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摘要
研究结构性黄土的次固结特性及机制,已成为黄土高填方地基工后沉降计算和控制的有效手段。本文通过对结构性黄土的压缩试验,研究了其次固结特性及变形机制,建立了描述次固结系数时间效应的关系式。试验结果表明,结构性黄土存在明显的次固结效应;荷载-次固结系数曲线(P-Cα)表现出先增加后减小,最终趋于稳定; Cα峰值对应荷载大于Pc,且高荷载将不是次固结系数的主要控制因素;在岩土破损力学框架内,分析了荷载、含水率对次固结系数影响的机制;水对土颗粒胶结作用的弱化使得高含水率结构性黄土的P-Cα曲线只呈现下降段和稳定段;建立了一种描述次固结系数时间效应的关系式,可对计算高填方下覆原有黄土地基的工后沉降提供帮助。
Study on secondary consolidation characteristics and mechanism of structured loess has become an effective means of calculating and controlling post-construction settlement in loess high fill foundation. In this paper,the secondary consolidation characteristics and deformation mechanism are studied by means of compression test of structured loess. Then the formula describing the time effect of secondary settlement coefficient is established.The test results show that an obvious secondary-consolidation effect exists in structured loess. The load coefficient of secondary consolidation curve(P-Cα) increases first and then decreases,and it finally tends to be stable. The peak of Cαcorresponding to the loading value is greater than Pc. High stress loads are not major controlling factor of the secondary consolidation coefficient. The influence mechanism of load and water content on secondary settlement coefficient is analyzed based on geotechnical mechanics. The P-Cαcurve of structured loess in high water content only decreases and tends to be a stable period by weakening effect of water on soil particles. Establishing the formula describing the time effect of secondary settlement coefficient can provide help for post-construction calculation of the covered original loess foundation in high fill engineering.
Study on secondary consolidation characteristics and mechanism of structured loess has become an effective means of calculating and controlling post-construction settlement in loess high fill foundation. In this paper,the secondary consolidation characteristics and deformation mechanism are studied by means of compression test of structured loess. Then the formula describing the time effect of secondary settlement coefficient is established.The test results show that an obvious secondary-consolidation effect exists in structured loess. The load coefficient of secondary consolidation curve(P-Cα) increases first and then decreases,and it finally tends to be stable. The peak of Cαcorresponding to the loading value is greater than Pc. High stress loads are not major controlling factor of the secondary consolidation coefficient. The influence mechanism of load and water content on secondary settlement coefficient is analyzed based on geotechnical mechanics. The P-Cαcurve of structured loess in high water content only decreases and tends to be a stable period by weakening effect of water on soil particles. Establishing the formula describing the time effect of secondary settlement coefficient can provide help for post-construction calculation of the covered original loess foundation in high fill engineering.
引文
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Chai H X,Cheng W M,Qiao Y L.2006.Classification system of 1︰1000000 digital loess geomorphology in China[J].GeoInformation Science,8(2):6-13.
Dong Q,Li Y,Duan X,et al.2016.In-situ tests on deformation laws of high foundation in loess plateau area[J].Journal of Engineering Geology,24(2):309-314.
Feng Z G,Zhu J G.2009.Experimental study on secondary consolidation behavior of soft soils[J].Journal of Hydraulic Engineering,40(5):583-588.
Ge M M,Li N,Zhu J G,et al.2015.Prediction of the post-construction settlement of high filled embankment with considering the time depending deformation of compacted loess[J].China Civil Engineering Journal,48(S2):262-267.
Gui Y,Yu Z H,Liu H M,et al.2015.Secondary consolidation properties and mechanism of plateau lacustrine peaty soil[J].Chinese Journal of Geotechnical Engineering,37(8):1390-1398.
Hu Y Y,Yang P,Yu Q Z.2016.Time effect of secondary consolidation coefficient of over-consolidated soil[J].China Journal of Highway and Transport,29(9):29-37.
Lei H Y,Ren Q,Zhang W Z,et al.2014.Consolidation property of ultra soft soil[J].Journal of Engineering Geology,22(6):1039-1045.
Liu E L,Shen Z J.2005.Binary medium model for structured soils[J].Journal of Hydraulic Engineering,36(4):391-395.
Luo Q Z,Wei X Y,Liu Q M,et al.2015.Experimental study on secondary consolidation of soft dredger fill[J].China Civil Engineering Journal,48(S2):257-261.
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Taylor D W,Merchant W A.1940.A theory of clay consolidation accounting for secondary compression[J].Studies in Applied Mathematics,19(1-4):167-185.
Yu X J,Yin Z Z,Dong W J.2007.Influence of load on secondary consolidation deformation of soft soils[J].Chinese Journal o Geotechnical Engineering,29(6):913-916.
Zeng L L,Liu S Y,Hong Z S,et al.2010.Deformation mechanism o secondary consolidation of natural clays[J].Chinese Journal o Geotechnical Engineering,32(7):1042-1046.
Zhou Q J,Chen X P.2006.Experimental study on creep characteristics o soft soils[J].Chinese Journal of Geotechnical Engineering,28(5):626-630.
Zhou Q J,Chen X P.2006.Test study on properties of secondary consolidation of soft soil[J].Rock and Soil Mechanics,27(3):404-408.
Zhu C H,Li N.2015.Post-construction settlement analysis of loess-high filling based on time-dependent deformation experiments[J].Rock and Soil Mechanics,36(10):3023-3031.
Zhu J G,Feng Z G.2009.Experimental study on behaviour of secondary consolidation of soft soils under repeatedly dumped loads[J].Chinese Journal of Geotechnical Engineering,31(3):341-345.
曹光栩,宋二祥,徐明.2011.山区机场高填方地基工后沉降变形简化算法[J].岩土力学,32(增1):1-5.
柴慧霞,程维明,乔玉良.2006.中国“数字黄土地貌”分类体系探讨[J].地球信息科学,8(2):6-13.
董琪,李阳,段旭,等.2016.黄土梁峁区高填方地基变形规律研究[J].工程地质学报,24(2):309-314.
冯志刚,朱俊高.2009.软土次固结变形特性试验研究[J].水利学报,40(5):583-588.
葛苗苗,李宁,郑建国,等.2015.考虑黄土时效变形特性的高填方工后沉降预测[J].土木工程学报,48(增刊2):262-267.
桂跃,余志华,刘海明,等.2015.高原湖相泥炭土次固结特性及机理分析[J].岩土工程学报,37(8):1390-1398.
胡亚元,杨平,余启致.2016.超固结土次固结系数的时间效应[J].中国公路学报,29(9):29-37.
雷华阳,任倩,张文振,等.2014.吹填超软土固结特性试验分析[J].工程地质学报,22(6):1039-1045.
刘恩龙,沈珠江.2005.结构性土的二元介质模型[J].水利学报,36(4):391-395.
罗庆姿,韦潇旖,刘荃铭,等.2015.吹填软土次固结特性的试验研究[J].土木工程学报,48(S2):257-261.
沈珠江,陈铁林.2002.岩石破损力学:基本概念、目标和任务[C]//中国岩石力学与工程学会第7次学术大会.宝鸡:中国岩石力学与工程学会:9-12.
孙明乾,王清,牛岑岑,等.2015.考虑次固结效应的流变固结理论研究[J].工程地质学报,23(4):675-680.
余湘娟,殷宗泽,董卫军.2007.荷载对软土次固结影响的试验研究[J].岩土工程学报,29(6):913-916.
曾玲玲,刘松玉,洪振舜,等.2010.天然沉积软黏土的次固结变形机理分析[J].岩土工程学报,32(7):1042-1046.
周秋娟,陈晓平.2006.软土次固结特性试验研究[J].岩土力学,27(3):404-408.
周秋娟,陈晓平.2006.软土蠕变特性试验研究[J].岩土工程学报,28(5):626-630.
朱才辉,李宁.2015.基于黄土变形时效试验的高填方工后沉降研究[J].岩土力学,36(10):3023-3031.
朱俊高,冯志刚.2009.反复荷载作用下软土次固结特性试验研究[J].岩土工程学报,31(3):341-345.
Cao G X,Song E X,Xu M.2011.Simplified calculation methods of postconstruction settlement of high-fill foundation in mountain airport[J].Rock and Soil Mechanics,32(S1):1-5.
Chai H X,Cheng W M,Qiao Y L.2006.Classification system of 1︰1000000 digital loess geomorphology in China[J].GeoInformation Science,8(2):6-13.
Dong Q,Li Y,Duan X,et al.2016.In-situ tests on deformation laws of high foundation in loess plateau area[J].Journal of Engineering Geology,24(2):309-314.
Feng Z G,Zhu J G.2009.Experimental study on secondary consolidation behavior of soft soils[J].Journal of Hydraulic Engineering,40(5):583-588.
Ge M M,Li N,Zhu J G,et al.2015.Prediction of the post-construction settlement of high filled embankment with considering the time depending deformation of compacted loess[J].China Civil Engineering Journal,48(S2):262-267.
Gui Y,Yu Z H,Liu H M,et al.2015.Secondary consolidation properties and mechanism of plateau lacustrine peaty soil[J].Chinese Journal of Geotechnical Engineering,37(8):1390-1398.
Hu Y Y,Yang P,Yu Q Z.2016.Time effect of secondary consolidation coefficient of over-consolidated soil[J].China Journal of Highway and Transport,29(9):29-37.
Lei H Y,Ren Q,Zhang W Z,et al.2014.Consolidation property of ultra soft soil[J].Journal of Engineering Geology,22(6):1039-1045.
Liu E L,Shen Z J.2005.Binary medium model for structured soils[J].Journal of Hydraulic Engineering,36(4):391-395.
Luo Q Z,Wei X Y,Liu Q M,et al.2015.Experimental study on secondary consolidation of soft dredger fill[J].China Civil Engineering Journal,48(S2):257-261.
Nash D F T,Sills G C,Davison L R.1992.One-dimensional consolidation testing of soft clay from Bothkennar[J].Géotechnique,42(2):241-256.
Shen Z J,Chen T L.2002.Breakage mechanics for geological materials basic concepts,goal and task[C]//Chinese Society for Rock Mechanics&Engineering Seventh Academic Conference.Baoji:Chinese Society for Rock Mechanics&Engineering:9-12.
Sun M Q,Wang Q,Niu C C,et al.2015.Rheological consolidation theory of soft soils with secondary consolidation effect[J].Journal o Engineering Geology,23(4):675-680.
Taylor D W,Merchant W A.1940.A theory of clay consolidation accounting for secondary compression[J].Studies in Applied Mathematics,19(1-4):167-185.
Yu X J,Yin Z Z,Dong W J.2007.Influence of load on secondary consolidation deformation of soft soils[J].Chinese Journal o Geotechnical Engineering,29(6):913-916.
Zeng L L,Liu S Y,Hong Z S,et al.2010.Deformation mechanism o secondary consolidation of natural clays[J].Chinese Journal o Geotechnical Engineering,32(7):1042-1046.
Zhou Q J,Chen X P.2006.Experimental study on creep characteristics o soft soils[J].Chinese Journal of Geotechnical Engineering,28(5):626-630.
Zhou Q J,Chen X P.2006.Test study on properties of secondary consolidation of soft soil[J].Rock and Soil Mechanics,27(3):404-408.
Zhu C H,Li N.2015.Post-construction settlement analysis of loess-high filling based on time-dependent deformation experiments[J].Rock and Soil Mechanics,36(10):3023-3031.
Zhu J G,Feng Z G.2009.Experimental study on behaviour of secondary consolidation of soft soils under repeatedly dumped loads[J].Chinese Journal of Geotechnical Engineering,31(3):341-345.
曹光栩,宋二祥,徐明.2011.山区机场高填方地基工后沉降变形简化算法[J].岩土力学,32(增1):1-5.
柴慧霞,程维明,乔玉良.2006.中国“数字黄土地貌”分类体系探讨[J].地球信息科学,8(2):6-13.
董琪,李阳,段旭,等.2016.黄土梁峁区高填方地基变形规律研究[J].工程地质学报,24(2):309-314.
冯志刚,朱俊高.2009.软土次固结变形特性试验研究[J].水利学报,40(5):583-588.
葛苗苗,李宁,郑建国,等.2015.考虑黄土时效变形特性的高填方工后沉降预测[J].土木工程学报,48(增刊2):262-267.
桂跃,余志华,刘海明,等.2015.高原湖相泥炭土次固结特性及机理分析[J].岩土工程学报,37(8):1390-1398.
胡亚元,杨平,余启致.2016.超固结土次固结系数的时间效应[J].中国公路学报,29(9):29-37.
雷华阳,任倩,张文振,等.2014.吹填超软土固结特性试验分析[J].工程地质学报,22(6):1039-1045.
刘恩龙,沈珠江.2005.结构性土的二元介质模型[J].水利学报,36(4):391-395.
罗庆姿,韦潇旖,刘荃铭,等.2015.吹填软土次固结特性的试验研究[J].土木工程学报,48(S2):257-261.
沈珠江,陈铁林.2002.岩石破损力学:基本概念、目标和任务[C]//中国岩石力学与工程学会第7次学术大会.宝鸡:中国岩石力学与工程学会:9-12.
孙明乾,王清,牛岑岑,等.2015.考虑次固结效应的流变固结理论研究[J].工程地质学报,23(4):675-680.
余湘娟,殷宗泽,董卫军.2007.荷载对软土次固结影响的试验研究[J].岩土工程学报,29(6):913-916.
曾玲玲,刘松玉,洪振舜,等.2010.天然沉积软黏土的次固结变形机理分析[J].岩土工程学报,32(7):1042-1046.
周秋娟,陈晓平.2006.软土次固结特性试验研究[J].岩土力学,27(3):404-408.
周秋娟,陈晓平.2006.软土蠕变特性试验研究[J].岩土工程学报,28(5):626-630.
朱才辉,李宁.2015.基于黄土变形时效试验的高填方工后沉降研究[J].岩土力学,36(10):3023-3031.
朱俊高,冯志刚.2009.反复荷载作用下软土次固结特性试验研究[J].岩土工程学报,31(3):341-345.