基于累积动应力水平的间歇加载下超孔压预测
|
摘要
设计一系列不同动应力幅值、间歇时长、振动时长的波形,对杭州地铁沿线淤泥质软黏土进行不排水单向循环加载试验,精确观测孔压累积过程。引入累积偏应力水平描述应力状态,分析对比各试验方案下归一化孔压随其变化的发展规律;分析动应力比、间歇时长、振动次数对超孔压累积的影响,发现动应力水平和振次的影响最为关键;从孔压增长机制的角度分析了间歇对于超孔压累积的影响;利用双曲函数拟合关系曲线,建立预测模型;通过分步拟合各振次关系曲线函数,发现振次不同时该模型的常数取值略有不同,分析常数随振动次数变化的规律,提出常数获取方法;最后利用该模型和既有模型预测新试样的超孔压发展,发现该模型表现良好。
This paper has performed a group of undrained unidirectional cyclic loading tests on undisturbed clay samples near planned metro line of Hangzhou. To simulate subway load, this paper has considered the characteristic that the trains always leave at intervals, so cyclic load is designed to consider regular intervals. Under cyclic loading with different amplitudes, dynamic loading durations and intervals durations, excess pore water pressure accumulations are observed. In this paper, the critical dynamic amplitude under cyclic loading with intervals is obtained and is found to be similar with that under cyclic loading without intervals. After that,an explicit model to calculate excess pore water pressure is built with an independent variable that describes cumulative dynamic deviator stress level. It is a new stress state parameter that can describe the effect of long-term dynamic loading in a cumulative way.The influence regulation of cumulative dynamic deviator stress level, vibration number and interval duration are presented and the dynamic deviator stress level and vibration number are much more important to excess pore water pressure accumulation than intervals. This explicit model is in the form of hyperbolic function with one major variable and a few constants. When predicting excess pore water pressure under different vibration numbers, these constants are also different but has relation with vibration number.The method to calculate the constants is also presented. In the end of this paper, testing results of several samples are presented to verify this model. Comparing the results predicted by the new model with an existing model with the measured data, the new model performs well.
This paper has performed a group of undrained unidirectional cyclic loading tests on undisturbed clay samples near planned metro line of Hangzhou. To simulate subway load, this paper has considered the characteristic that the trains always leave at intervals, so cyclic load is designed to consider regular intervals. Under cyclic loading with different amplitudes, dynamic loading durations and intervals durations, excess pore water pressure accumulations are observed. In this paper, the critical dynamic amplitude under cyclic loading with intervals is obtained and is found to be similar with that under cyclic loading without intervals. After that,an explicit model to calculate excess pore water pressure is built with an independent variable that describes cumulative dynamic deviator stress level. It is a new stress state parameter that can describe the effect of long-term dynamic loading in a cumulative way.The influence regulation of cumulative dynamic deviator stress level, vibration number and interval duration are presented and the dynamic deviator stress level and vibration number are much more important to excess pore water pressure accumulation than intervals. This explicit model is in the form of hyperbolic function with one major variable and a few constants. When predicting excess pore water pressure under different vibration numbers, these constants are also different but has relation with vibration number.The method to calculate the constants is also presented. In the end of this paper, testing results of several samples are presented to verify this model. Comparing the results predicted by the new model with an existing model with the measured data, the new model performs well.
引文
[1]张炜,李亚,周松望,等.南海北部区域黏土循环动力特性试验研究[J].岩土力学,2018,39(7):2413-2423.ZHANG Wei,LI Ya,ZHOU Song-wang,et al.Experimental research on cyclic behaviors of clay in the northern region of South China Sea[J].Rock and Soil Mechanics,2018,39(7):2413-2423.
[2]胡秀青,张艳,符洪涛,等.水平双向荷载耦合对饱和软黏土动力特性的影响[J].岩土力学,2018,39(3):839-847.HU Xiu-qing,ZHANG Yan,FU Hong-tao,et al.Effect of horizontal bidirectional coupled loads on dynamic properties of saturated soft clay[J].Rock and Soil Mechanics,2018,39(3):839-847.
[3]沈扬,徐海东,王保光,等.列车荷载引起心形应力路径下软土非共轴应变特征研究[J].岩土力学,2017,38(1):1-9.SHEN Yang,XU Hai-dong,WANG Bao-guang,et al.Strain characteristics of non-coaxiality under heartshaped stress path caused by train loads in soft clay[J].Rock and Soil Mechanics,2017,38(1):1-9.
[4]GUO L,WANG J,CAI Y Q,et al.Undrained deformation behavior of saturated soft clay under long-term cyclic loading[J].Soil Dynamics and Earthquake Engineering,2013,50:28-37.
[5]周建.循环荷载作用下饱和软黏土的孔压模型[J].工程勘察,2000(4):7-9.ZHOU Jian.Pore pressure model of saturated soft clay under circulating load[J].Geotechnical Investigation and Surveying,2000(4):7-9.
[6]王元东,唐益群,廖少明,等.地铁行车荷载下隧道周围加固软黏土孔压特性试验[J].吉林大学学报(地球科学版),2011,41(1):188-194.WANG Yuan-dong,TANG Yi-qun,LIAO Shao-ming,et al.Experimental of pore pressure of reinforced soft clay around tunnel under subway vibrational loading[J].Journal of Jilin University(Earth Science Edition),2011,41(1):188-194.
[7]许才军,周红波.不排水循环荷载作用下饱和软黏土的孔压增长模型[J].勘察科学技术,1998(1):3-7.XU Cai-jun,ZHOU Hong-bo.Pore pressure increase model of saturated soft clay under undrained cyclic load[J].Site Investigation Science and Technology,1998(1):3-7.
[8]叶俊能,陈斌.海相沉积软土动强度与孔压特性试验研究[J].岩土力学,2011,32(增刊1):55-60.YE Jun-neng,CHEN Bin.Dynamic strength and pore pressure property of marine deposit soft clay[J].Rock and Soil Mechanics,2011,32(Suppl.1):55-60.
[9]章克凌,陶振宇.饱和黏土在循环荷载作用下的孔压预测[J].岩土力学,1994,15(3):9-17.ZHANG Ke-ling,TAO Zhen-yu.The prediction of pore pressure of saturated clay under cyclic loading[J].Rock and Soil Mechanics,1994,15(3):9-17.
[10]OHARA S,MATSUDA H,KONDO Y.Cyclic simple shear tests on saturated clay with drainage[J].Doboku Gakkai Ronbunshu,1984(352):149-158.
[11]MONISMITH C L,OGAWA N,FREEME C R.Permanent deformation characteristics of subgrade soils due to repeated loading[J].Transportation Research Record,1975,537:1-17.
[12]MATASOVIC N,VUCETIC M.Generalized cyclicdegradation-pore-pressure generation model for clays[J].Journal of Geotechnical Engineering,1995,121(1):33-42.
[13]雷华阳.天津地区海积软土的孔压模型建立及参数确定[J].吉林大学学报(地球科学版),2003,33(1):76-79.LEI Hua-yang.Pore pressure model of marine soft soil and its parameters in Tianjin region[J].Journal of Jilin University(Earth Science Edition),2003,33(1):76-79.
[14]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 Mao-song,LI Jin-jun,LI Xing-zhao.Cumulative deformation behaviour of soft clay in cyclic undrained tests[J].Chinese Journal of Geotechnical Engineering,2006,28(7):891-895.
[15]赵春彦,周顺华,庄丽.上海地区软土的循环累积孔压模型[J].铁道学报,2012,34(1):77-82.ZHAO Chun-yan,ZHOU Shun-hua,ZHUANG Li.Cyclic accumulative pore pressure model of soft clay in the Shanghai region[J].Journal of the China Railway Society,2012,34(1):77-82.
[16]MATSUDA H,NHAN T T,ISHIKURA R.Prediction of excess pore water pressure and post-cyclic settlement on soft clay induced by uni-directional and multi-directional cyclic shears as a function of strain path parameters[J].Soil Dynamics and Earthquake Engineering,2013,49:75-88.
[17]顾中华.循环荷载作用下偏压固结饱和黏土孔压模型[J].地下空间与工程学报,2007,3(4):776-780.GU Zhong-hua.The excess pore-water pressure model of anisotropic consolidated saturated clay under cyclic loading[J].Chinese Journal of Underground Space and Engineering,2007,3(4):776-780.
[18]周建,龚晓南,李剑强.循环荷载作用下饱和软黏土特性试验研究[J].工业建筑,2000,30(11):43-47,4.ZHOU Jian,GONG Xiao-nan,LI Jian-qiang.Experimental study of saturated soft clay under cyclic loading[J].Industrial construction,2000,30(11):43-47,4.
[2]胡秀青,张艳,符洪涛,等.水平双向荷载耦合对饱和软黏土动力特性的影响[J].岩土力学,2018,39(3):839-847.HU Xiu-qing,ZHANG Yan,FU Hong-tao,et al.Effect of horizontal bidirectional coupled loads on dynamic properties of saturated soft clay[J].Rock and Soil Mechanics,2018,39(3):839-847.
[3]沈扬,徐海东,王保光,等.列车荷载引起心形应力路径下软土非共轴应变特征研究[J].岩土力学,2017,38(1):1-9.SHEN Yang,XU Hai-dong,WANG Bao-guang,et al.Strain characteristics of non-coaxiality under heartshaped stress path caused by train loads in soft clay[J].Rock and Soil Mechanics,2017,38(1):1-9.
[4]GUO L,WANG J,CAI Y Q,et al.Undrained deformation behavior of saturated soft clay under long-term cyclic loading[J].Soil Dynamics and Earthquake Engineering,2013,50:28-37.
[5]周建.循环荷载作用下饱和软黏土的孔压模型[J].工程勘察,2000(4):7-9.ZHOU Jian.Pore pressure model of saturated soft clay under circulating load[J].Geotechnical Investigation and Surveying,2000(4):7-9.
[6]王元东,唐益群,廖少明,等.地铁行车荷载下隧道周围加固软黏土孔压特性试验[J].吉林大学学报(地球科学版),2011,41(1):188-194.WANG Yuan-dong,TANG Yi-qun,LIAO Shao-ming,et al.Experimental of pore pressure of reinforced soft clay around tunnel under subway vibrational loading[J].Journal of Jilin University(Earth Science Edition),2011,41(1):188-194.
[7]许才军,周红波.不排水循环荷载作用下饱和软黏土的孔压增长模型[J].勘察科学技术,1998(1):3-7.XU Cai-jun,ZHOU Hong-bo.Pore pressure increase model of saturated soft clay under undrained cyclic load[J].Site Investigation Science and Technology,1998(1):3-7.
[8]叶俊能,陈斌.海相沉积软土动强度与孔压特性试验研究[J].岩土力学,2011,32(增刊1):55-60.YE Jun-neng,CHEN Bin.Dynamic strength and pore pressure property of marine deposit soft clay[J].Rock and Soil Mechanics,2011,32(Suppl.1):55-60.
[9]章克凌,陶振宇.饱和黏土在循环荷载作用下的孔压预测[J].岩土力学,1994,15(3):9-17.ZHANG Ke-ling,TAO Zhen-yu.The prediction of pore pressure of saturated clay under cyclic loading[J].Rock and Soil Mechanics,1994,15(3):9-17.
[10]OHARA S,MATSUDA H,KONDO Y.Cyclic simple shear tests on saturated clay with drainage[J].Doboku Gakkai Ronbunshu,1984(352):149-158.
[11]MONISMITH C L,OGAWA N,FREEME C R.Permanent deformation characteristics of subgrade soils due to repeated loading[J].Transportation Research Record,1975,537:1-17.
[12]MATASOVIC N,VUCETIC M.Generalized cyclicdegradation-pore-pressure generation model for clays[J].Journal of Geotechnical Engineering,1995,121(1):33-42.
[13]雷华阳.天津地区海积软土的孔压模型建立及参数确定[J].吉林大学学报(地球科学版),2003,33(1):76-79.LEI Hua-yang.Pore pressure model of marine soft soil and its parameters in Tianjin region[J].Journal of Jilin University(Earth Science Edition),2003,33(1):76-79.
[14]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 Mao-song,LI Jin-jun,LI Xing-zhao.Cumulative deformation behaviour of soft clay in cyclic undrained tests[J].Chinese Journal of Geotechnical Engineering,2006,28(7):891-895.
[15]赵春彦,周顺华,庄丽.上海地区软土的循环累积孔压模型[J].铁道学报,2012,34(1):77-82.ZHAO Chun-yan,ZHOU Shun-hua,ZHUANG Li.Cyclic accumulative pore pressure model of soft clay in the Shanghai region[J].Journal of the China Railway Society,2012,34(1):77-82.
[16]MATSUDA H,NHAN T T,ISHIKURA R.Prediction of excess pore water pressure and post-cyclic settlement on soft clay induced by uni-directional and multi-directional cyclic shears as a function of strain path parameters[J].Soil Dynamics and Earthquake Engineering,2013,49:75-88.
[17]顾中华.循环荷载作用下偏压固结饱和黏土孔压模型[J].地下空间与工程学报,2007,3(4):776-780.GU Zhong-hua.The excess pore-water pressure model of anisotropic consolidated saturated clay under cyclic loading[J].Chinese Journal of Underground Space and Engineering,2007,3(4):776-780.
[18]周建,龚晓南,李剑强.循环荷载作用下饱和软黏土特性试验研究[J].工业建筑,2000,30(11):43-47,4.ZHOU Jian,GONG Xiao-nan,LI Jian-qiang.Experimental study of saturated soft clay under cyclic loading[J].Industrial construction,2000,30(11):43-47,4.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |