不同荷载振动模式下软黏土动力特性试验研究
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摘要
针对宁波轨道交通影响范围内的④2层淤泥质黏土开展了不同振动模式下的动三轴试验,获得了单向纯压振动和单向拉压振动模式下的孔压、累积塑形应变和动弹性模量的变化规律,建立了孔压—振动次数、累积塑性应变—振动次数的指数函数关系,结果表明:静偏应力的不同为两种振动模式的本质区别;单向拉压振动下的孔压稳定所需的振动次数较单向纯压振动大,累积塑性应变比单向纯压振动小一个数量级;单向拉压振动产生的弹性应变较单向纯压振动大,动弹性模量则反之;所建立的描述孔压、累积塑性应变与振动次数关系的指数函数能较好地反映孔压、累积塑性应变斜率随振动次数的变化规律,研究结果可以为轨道交通设计和施工提供理论依据。
Dynamic triaxial tests for different cycle loading modes were carried out on the④2 layer silty clay of Ningbo rail transit,and the pore pressure,cumulative shaping strain and dynamics of the clay under one-way load vibration mode and two-way load vibration modes were obtained.Also an exponential function of pore pressure and vibration frequency,and cumulative plastic strain and vibration frequency was established.The results show that the difference of static deviator stress is the essential difference between the two vibration modes;the number of vibrations required for the stability of pore pressure under unidirectional tension and pressure vibration is greater than that of one-way pure pressure,and the cumulative plastic strain ratio is more than one-way pure pressure.The vibration is an order of magnitude smaller;the elastic strain generated by the unidirectional tension and compression vibration is greater than the unidirectional pure pressure vibration,and the dynamic elastic modulus is the reverse;the exponential function established to describe the relationship between the pore pressure,cumulative plastic strain and the number of vibrations revealed greatly the variation of pore pressure and cumulative plastic strain slope with the number of vibrations.The research results can provide a theoretical basis for rail transit design and construction.
Dynamic triaxial tests for different cycle loading modes were carried out on the④2 layer silty clay of Ningbo rail transit,and the pore pressure,cumulative shaping strain and dynamics of the clay under one-way load vibration mode and two-way load vibration modes were obtained.Also an exponential function of pore pressure and vibration frequency,and cumulative plastic strain and vibration frequency was established.The results show that the difference of static deviator stress is the essential difference between the two vibration modes;the number of vibrations required for the stability of pore pressure under unidirectional tension and pressure vibration is greater than that of one-way pure pressure,and the cumulative plastic strain ratio is more than one-way pure pressure.The vibration is an order of magnitude smaller;the elastic strain generated by the unidirectional tension and compression vibration is greater than the unidirectional pure pressure vibration,and the dynamic elastic modulus is the reverse;the exponential function established to describe the relationship between the pore pressure,cumulative plastic strain and the number of vibrations revealed greatly the variation of pore pressure and cumulative plastic strain slope with the number of vibrations.The research results can provide a theoretical basis for rail transit design and construction.
引文
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[3]陈颖平,黄博,陈云敏.循环荷载作用下软黏土不排水累积变形特性[J].岩土工程学报,2008,30(5):764-768.Chen Y L,Huang B,Chen Y M.Reliability analysis of high level backfill based on chaotic optimization[J].Chinese Journal of Geotechnical Engineering,2008,30(5):764-768.(in Chinese)
[4]黄茂松,李进军,李兴照.饱和软黏土的不排水循环累积变形特性[J].岩土工程学报,2006,28(7):891-895.Huang M S,Li J J,Li X Zh.Cumulative deformation behaviour of soft clay in cyclic undrained tests[J].Chinese Journal of Geotechnical Engineering,2006,28(7):891-895.(in Chinese)
[5]蔡骁,高洪梅,赵晖,等.轨道交通荷载作用下EPS颗粒轻质混合土的动力特性研究[J].防灾减灾工程学报,2015(5):651-658.Cai X,Gao H M,Zhao H,et al.Dynamic characteristics of EPS composite lightweight soil under railway load[J].Journal of Disaster Prevention and Mitigation Engineering,2015(5):651-658.(in Chinese)
[6]王炳辉,陈国兴,王晶华.宁波近海沉积土动力特性的试验研究[J].自然灾害学报,2007,16(4):55-60.Wang B H,Chen G X,Wang J H.Experimental study on dynamic characteristics of Ningbo’s offshores ediment soils[J].Journal of Natural Disasters,2007,16(4):55-60.(in Chinese)
[7]刘干斌,范思婷,陈斌,等.考虑温度影响的饱和软黏土累积变形特性研究[J].岩土工程学报,2016,38(7):1 238-1 245.Liu G B,Fan S T,Chen B,et al.Characteristics of cumulative deformation of saturated soft clay considering temperature effect[J].Chinese Journal of Geotechnical Engineering,2016,38(7):1 238-1 245.(in Chinese)
[8]王军,陈春雷,丁光亚.循环荷载下温州超固结软土动强度与变形分析[J].自然灾害学报,2009,18(4):125-131.Wang J,Chen Ch L,Ding G Y.Analysis of dynamic strength and deformation of Wenzhou over consolidated soft clay under cyclic loading[J].Journal of Natural Disasters,2009,18(4):125-131.(in Chinese)
[9]刘文化,杨庆,唐小微,等.交通荷载作用下非饱和土的动力特性试验研究[J].防灾减灾工程学报,2015(2):263-269.Liu W H,Yang Q,Tang X W,et al.Experimental study on dynamic characteristics of unsaturated soil under traffic loading[J].Journal of Disaster Prevention and Mitigation Engineering,2015(2):263-269.(in Chinese)
[10]陈成,周正明,张先伟,等.循环荷载作用下泥炭质土动力累积特性试验研究.岩石力学与工程学报,2017,36(5):1 247-1 254.Chen Ch,Zhou Zh M,Zhang X W,et al.Experimental study on accumulative behaviour of peaty soil under cyclic loading[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(5):1 247-1 254.(in Chinese)
[11]Yasuhara K,Hirao K,Hyde A F L.Effects of cyclic loading on undrained strength and compressibility of clay[J].Soils and Foundations,1992,32(1):100-116.
[12]Andersen K H,Lauritzsen R.Bearing capacity for foundations with cyclic loads[J].Journal of Geotechnical Engineering,ASCE,1988,114(5):540-555.
[13]土工试验方法标准:GB/TS0123-1999[S].北京:中国计划出版社,1999.Geotechnical test method standard:GB/TS0123-1999[S].Beijing:China Planning Press,1999.(in Chinese)