饱和重塑黄土抗剪强度影响因素的试验研究
|
摘要
强降雨和灌溉导致黄土强度劣化并发生饱和破坏现象,进而诱发黄土滑坡,给当地带来严重的灾难。饱和黄土抗剪强度的影响因素较多,本文根据水头饱和与反压饱和相结合的原理,利用改装后的TFB-1型非饱和土应力-应变控制式三轴仪对党川地区马兰黄土重塑土样进行饱和试验和CU试验。分别采用50 kPa、100 kPa、200 kPa、400 kPa围压对饱和重塑黄土进行剪切速率分别为0.02 mm·min~(-1)、0.06 mm·min~(-1)、0.2 mm·min~(-1)、0.4 mm·min~(-1)的CU试验,探讨了围压和剪切速率对饱和重塑黄土抗剪强度的影响。研究发现:同一围压下,饱和重塑黄土的抗剪强度随着剪切速率的增大呈先增大后减小的趋势;同一剪切速率下,饱和重塑黄土的抗剪强度随着围压的增大逐渐增大;在干密度相同的条件下,饱和重塑黄土的总黏聚力及有效黏聚力随着剪切速率的增大先减小后增大,总内摩擦角及有效内摩擦角随着剪切速率的增大先增大后减小。该研究可为黄土滑坡预报和范围预测提供一定依据。
The saturated liquefaction failure of loess occurs frequently in the loess area due to heavy rainfall and irrigation,and induces loess landslide and brings huge economic loss to the local people. The shear strength of saturated loess is influenced by many factors. So saturation experiments of remolded loess of Malan loess in Dangchuan district are carried on the modified TFB-1 type triaxial apparatus of stress and strain controlled for unsaturated soil through the combination of hydraulic saturation and back pressure saturation. The saturated remolded soil samples are conducted on consolidated undrained test under the conditions of the confining pressure of50 kPa,100 kPa,200 kPa and 400 kPa respectively,and the shear rate of 0. 02 mm·min~(-1),0. 06 mm·min~(-1),0. 2 mm·min~(-1) and 0. 4 mm·min~(-1) respectively. The influence of confining pressure and shear rate on the shear strength of saturated loess is discussed. The results show that the shear strength of the saturated remolded loess increases first and then decreases with the increase of shear rate under the same confining pressure. The shearstrength of the saturated remolded loess is higher with the increase of confining pressure under the same shear rate.The total cohesion and the effective cohesion of the remolded loess increase first and then decrease with the shear rate under the same dry density. The total internal friction angle and the effective internal friction angle increase first and then decrease with the increase of shear rate. The study can provide a basis for loess landslide prediction and scope.
The saturated liquefaction failure of loess occurs frequently in the loess area due to heavy rainfall and irrigation,and induces loess landslide and brings huge economic loss to the local people. The shear strength of saturated loess is influenced by many factors. So saturation experiments of remolded loess of Malan loess in Dangchuan district are carried on the modified TFB-1 type triaxial apparatus of stress and strain controlled for unsaturated soil through the combination of hydraulic saturation and back pressure saturation. The saturated remolded soil samples are conducted on consolidated undrained test under the conditions of the confining pressure of50 kPa,100 kPa,200 kPa and 400 kPa respectively,and the shear rate of 0. 02 mm·min~(-1),0. 06 mm·min~(-1),0. 2 mm·min~(-1) and 0. 4 mm·min~(-1) respectively. The influence of confining pressure and shear rate on the shear strength of saturated loess is discussed. The results show that the shear strength of the saturated remolded loess increases first and then decreases with the increase of shear rate under the same confining pressure. The shearstrength of the saturated remolded loess is higher with the increase of confining pressure under the same shear rate.The total cohesion and the effective cohesion of the remolded loess increase first and then decrease with the shear rate under the same dry density. The total internal friction angle and the effective internal friction angle increase first and then decrease with the increase of shear rate. The study can provide a basis for loess landslide prediction and scope.
引文
Chen G X,Jin D D,Chang X D,et al.2013.Review of soil liquefaction characteristics during major earthquakes in recent twenty years and liquefaction susceptibility criteria for soils[J].Rock and Soil Mechanics,34(10):2737-2755,2795.
Chen W W,Liu W,Sun G P,et al.2014.Triaxial test on saturation and consolidation of remolded loess[J].Journal of Engineering Geology,22(5):839-844.
Dang J Q,Jiang C L,Ji Z L.2009.Effects of shear rate on mechanical behavior of structured loess[J].Chinese Journal of Underground Space and Engineering,5(3):459-462,540.
Hu W N,Pan X,Kou M Z,et al.2013.On shear rate on saturated silty clay test results in direct shear test[J].Port and Waterway Engineering,(8):173-177.
Ji H,Zhang T.2015.Influence of shearing rate on strength properties of saturated loess[J].Journal of Electric Power,30(5):451-456.
Lin H Z,Li G X,Yu Y Z,et al.2007.Influence of matric suction on shear strength behavior of unsaturated soils[J].Rock and Soil Mechanics,28(9):1931-1936.
Li G X,Zhang B Y,Yu Y Z.2013.Soil Mechanics[M].Beijing:Tsinghua University Press.
Niu J X,Jie Z L,LüY C.2014.Test study on influence of shear rate upon shear strength of unsaturated loess[J].Shanxi Architecture,40(26):68-69.
Shen C N,Fang X W,Wang H W,et al.2009.Research on effects of suction,water content and dry density on shear strength of remolded unsaturated soils[J].Rock and Soil Mechanics,30(5):1347-1351.
The Professional Standards Compilation Group of People's Republic of China.1999.Standard for soil test method(GB/T50123-1999)[S].Beijing:China Planning Press.
Wang Y F,Dong J J,Cheng Q G.2017.Velocity-dependent frictional weakening of large rock avalanche basal facies:Implications for rock avalanche hypermobility?[J].Journal of Geophysical Research Solid Earth,122:1648-1676.
Wu C X,Xu L,Dai F C,et al.2011.Topographic features and initiation of earth flows on Heifangtai loess plateau[J].Rock and Soil Mechanics,32(6):1767-1773.
Xing X L,Li T L,Li P,et al.2014.Variation regularities of loess shear strength with the moisture content[J].Hydrogeology and Engineering Geology,41(3):53-59,97.
Xu L,Dai F C,Kuang G L,et al.2008.Types and characteristics of loess landslides at Heifangtai loess plateau,China[J].Journal of Mountain Science,26(3):364-371.
Xu L,Dai F C,Ming H,et al.2010.Loess landslide types and topographic features at south Jingyang Plateau,China[J].Earth ScienceJournal of China University of Geosciences,35(1):155-160.
Xu Z J,Lin Z G,Zhang M S.2007.Loess in China and loess landslides[J].Chinese Journal of Rock Mechanics and Engineering,26(7):1297-1312.
Yang P.2007.Influence of stress path on deformation and strength characteristics of saturated intact loess[D].Xi'an:Northwestern Polytechnic University.
Zhang X C.2015.Experimental study on mechanism of Shibeiyuan loess landslide triggered by earthquake[D].Chengdu:Chengdu University of Technology.
陈国兴,金丹丹,常向东,等.2013.最近20年地震中场地液化现象的回顾与土体液化可能性的评价准则[J].岩土力学,34(10):2737-2755,2795.
谌文武,刘伟,孙冠平,等.2014.重塑黄土饱和与固结时间三轴试验研究[J].工程地质学报,22(5):839-844.
党进谦,蒋仓兰,吉中亮.2009.剪切速率对结构性黄土力学性状的影响[J].地下空间与工程学报,5(3):459-462,540.
胡伟娜,潘璇,寇明珠,等.2013.剪切速率对饱和粉质黏土快剪指标影响分析[J].水运工程,(8):173-177.
冀慧,张涛.2015.剪切速率对饱和黄土强度特性的影响[J].电力学报,30(5):451-456.
林鸿州,李广信,于玉贞,等.2007.基质吸力对非饱和土抗剪强度的影响[J].岩土力学,28(9):1931-1936.
李广信,张丙印,于玉贞.2013.土力学[M].北京:清华大学出版社.
牛军贤,颉铎铃,吕耀成.2014.剪切速率对非饱和黄土抗剪强度影响的试验研究[J].山西建筑,40(26):68-69.
申春妮,方祥位,王和文,等.2009.吸力、含水率和干密度对重塑非饱和土抗剪强度影响研究[J].岩土力学,30(5):1347-1351.
武彩霞,许领,戴福初,等.2011.黑方台黄土泥流滑坡及发生机制研究[J].岩土力学,32(6):1767-1773.
邢鲜丽,李同录,李萍,等.2014.黄土抗剪强度与含水率的变化规律[J].水文地质工程地质,41(3):53-59,97.
徐张建,林在贯,张茂省.2007.中国黄土与黄土滑坡[J].岩石力学与工程学报,26(7):1297-1312.
许领,戴福初,邝国麟,等.2008.黑方台黄土滑坡类型与发育规律[J].山地学报,26(3):364-371.
许领,戴福初,闵弘,等.2010.泾阳南塬黄土滑坡类型与发育特征[J].地球科学---中国地质大学学报,35(1):155-160.
杨鹏.2007.应力路径对饱和原状黄土的变形强度特性的影响[D].西安:西安理工大学.
张晓超.2015.地震诱发石碑塬低角度黄土滑坡形成机理的试验研究[D].成都:成都理工大学.
中华人民共和国行业标准编写组.1999.土工试验方法标准(GB/T50123-1999)[S].北京:中国计划出版社.
Chen W W,Liu W,Sun G P,et al.2014.Triaxial test on saturation and consolidation of remolded loess[J].Journal of Engineering Geology,22(5):839-844.
Dang J Q,Jiang C L,Ji Z L.2009.Effects of shear rate on mechanical behavior of structured loess[J].Chinese Journal of Underground Space and Engineering,5(3):459-462,540.
Hu W N,Pan X,Kou M Z,et al.2013.On shear rate on saturated silty clay test results in direct shear test[J].Port and Waterway Engineering,(8):173-177.
Ji H,Zhang T.2015.Influence of shearing rate on strength properties of saturated loess[J].Journal of Electric Power,30(5):451-456.
Lin H Z,Li G X,Yu Y Z,et al.2007.Influence of matric suction on shear strength behavior of unsaturated soils[J].Rock and Soil Mechanics,28(9):1931-1936.
Li G X,Zhang B Y,Yu Y Z.2013.Soil Mechanics[M].Beijing:Tsinghua University Press.
Niu J X,Jie Z L,LüY C.2014.Test study on influence of shear rate upon shear strength of unsaturated loess[J].Shanxi Architecture,40(26):68-69.
Shen C N,Fang X W,Wang H W,et al.2009.Research on effects of suction,water content and dry density on shear strength of remolded unsaturated soils[J].Rock and Soil Mechanics,30(5):1347-1351.
The Professional Standards Compilation Group of People's Republic of China.1999.Standard for soil test method(GB/T50123-1999)[S].Beijing:China Planning Press.
Wang Y F,Dong J J,Cheng Q G.2017.Velocity-dependent frictional weakening of large rock avalanche basal facies:Implications for rock avalanche hypermobility?[J].Journal of Geophysical Research Solid Earth,122:1648-1676.
Wu C X,Xu L,Dai F C,et al.2011.Topographic features and initiation of earth flows on Heifangtai loess plateau[J].Rock and Soil Mechanics,32(6):1767-1773.
Xing X L,Li T L,Li P,et al.2014.Variation regularities of loess shear strength with the moisture content[J].Hydrogeology and Engineering Geology,41(3):53-59,97.
Xu L,Dai F C,Kuang G L,et al.2008.Types and characteristics of loess landslides at Heifangtai loess plateau,China[J].Journal of Mountain Science,26(3):364-371.
Xu L,Dai F C,Ming H,et al.2010.Loess landslide types and topographic features at south Jingyang Plateau,China[J].Earth ScienceJournal of China University of Geosciences,35(1):155-160.
Xu Z J,Lin Z G,Zhang M S.2007.Loess in China and loess landslides[J].Chinese Journal of Rock Mechanics and Engineering,26(7):1297-1312.
Yang P.2007.Influence of stress path on deformation and strength characteristics of saturated intact loess[D].Xi'an:Northwestern Polytechnic University.
Zhang X C.2015.Experimental study on mechanism of Shibeiyuan loess landslide triggered by earthquake[D].Chengdu:Chengdu University of Technology.
陈国兴,金丹丹,常向东,等.2013.最近20年地震中场地液化现象的回顾与土体液化可能性的评价准则[J].岩土力学,34(10):2737-2755,2795.
谌文武,刘伟,孙冠平,等.2014.重塑黄土饱和与固结时间三轴试验研究[J].工程地质学报,22(5):839-844.
党进谦,蒋仓兰,吉中亮.2009.剪切速率对结构性黄土力学性状的影响[J].地下空间与工程学报,5(3):459-462,540.
胡伟娜,潘璇,寇明珠,等.2013.剪切速率对饱和粉质黏土快剪指标影响分析[J].水运工程,(8):173-177.
冀慧,张涛.2015.剪切速率对饱和黄土强度特性的影响[J].电力学报,30(5):451-456.
林鸿州,李广信,于玉贞,等.2007.基质吸力对非饱和土抗剪强度的影响[J].岩土力学,28(9):1931-1936.
李广信,张丙印,于玉贞.2013.土力学[M].北京:清华大学出版社.
牛军贤,颉铎铃,吕耀成.2014.剪切速率对非饱和黄土抗剪强度影响的试验研究[J].山西建筑,40(26):68-69.
申春妮,方祥位,王和文,等.2009.吸力、含水率和干密度对重塑非饱和土抗剪强度影响研究[J].岩土力学,30(5):1347-1351.
武彩霞,许领,戴福初,等.2011.黑方台黄土泥流滑坡及发生机制研究[J].岩土力学,32(6):1767-1773.
邢鲜丽,李同录,李萍,等.2014.黄土抗剪强度与含水率的变化规律[J].水文地质工程地质,41(3):53-59,97.
徐张建,林在贯,张茂省.2007.中国黄土与黄土滑坡[J].岩石力学与工程学报,26(7):1297-1312.
许领,戴福初,邝国麟,等.2008.黑方台黄土滑坡类型与发育规律[J].山地学报,26(3):364-371.
许领,戴福初,闵弘,等.2010.泾阳南塬黄土滑坡类型与发育特征[J].地球科学---中国地质大学学报,35(1):155-160.
杨鹏.2007.应力路径对饱和原状黄土的变形强度特性的影响[D].西安:西安理工大学.
张晓超.2015.地震诱发石碑塬低角度黄土滑坡形成机理的试验研究[D].成都:成都理工大学.
中华人民共和国行业标准编写组.1999.土工试验方法标准(GB/T50123-1999)[S].北京:中国计划出版社.