武汉鹏湖湾地区老黏土动力响应特性及强度弱化规律研究
|
摘要
岩溶区老黏土在人类工程活动所引起的动荷载作用下,会产生动力变形特性的改变,强度参数也会发生相应的弱化,最终导致土洞上覆盖层结构性的破坏。以武汉市鹏湖湾地区的老黏土为研究对象,结合该岩溶塌陷场地的工程地质条件,开展相应的室内动三轴试验,研究老黏土在围压、动应力比和循环次数等因素变化时的动力响应特性和强度弱化规律,提出其在循环荷载作用下的强度弱化模型。结果表明,随着围压、动应力比及循环次数的增加,老黏土的孔隙水压力有所提高。当其它因素保持不变,且动应力比与循环次数不超过某一临界值时,土体的强度随着动应力比、循环次数的增加而降低,即超孔压的增长引起老黏土强度的衰减。而在围压增长的初期,土体的强度与围压成正比,当围压增大到某一临界值时,老黏土的抗剪强度显著降低。强度折减率随围压、动应力比、循环次数的增加均有不同程度的降低,提取出经验公式,得到的老黏土强度弱化模型具有较高的相关性,进一步得出老黏土的强度弱化机理。
The old clay in the karst area can change its dynamic deformation characteristics and weak the intensity parameters correspondingly under the dynamic load caused by human engineering activities,which may leading to the structural damage on soil cave eventually. The old clay in Penghu Bay of Wuhan City was taken as the study object. Combined with the engineering geological conditions of the karst collapse site,the indoor dynamic triaxial test of the old clay was carried out to study the dynamic deformation characteristics and the strength weakening lawunder the influence of the factors such as dynamic stress ratio,confining pressure and cycle times,then the strength weakening model under cyclic loading was proposed. The results show that the pore water pressure of the old clay increases with the increase of the confining pressure and the dynamic stress ratio and the number of cycles. When the dynamic stress ratio and the cycling numbers do not exceed a certain critical value,the strength of the soil increases with the enhancing of dynamic stress ratio and the number of cycles,that is to say the increase in pore pressure triggers the attenuation of soil strength. In the early raising period of confining pressure,the strength of soil increases with the addition of confining pressure. When the confining pressure increases until the soil structural damaged,the shear strength of the old clay is greatly reduced. The strength reduction rate decreases correspondingly with the increase of the confining pressure,dynamic stress ratio and the number of cycles. The correlation of the old clay strength weakening model obtained with empirical formula is fairly high. The weakening mechanism of the strength of the old clay is further obtained.
The old clay in the karst area can change its dynamic deformation characteristics and weak the intensity parameters correspondingly under the dynamic load caused by human engineering activities,which may leading to the structural damage on soil cave eventually. The old clay in Penghu Bay of Wuhan City was taken as the study object. Combined with the engineering geological conditions of the karst collapse site,the indoor dynamic triaxial test of the old clay was carried out to study the dynamic deformation characteristics and the strength weakening lawunder the influence of the factors such as dynamic stress ratio,confining pressure and cycle times,then the strength weakening model under cyclic loading was proposed. The results show that the pore water pressure of the old clay increases with the increase of the confining pressure and the dynamic stress ratio and the number of cycles. When the dynamic stress ratio and the cycling numbers do not exceed a certain critical value,the strength of the soil increases with the enhancing of dynamic stress ratio and the number of cycles,that is to say the increase in pore pressure triggers the attenuation of soil strength. In the early raising period of confining pressure,the strength of soil increases with the addition of confining pressure. When the confining pressure increases until the soil structural damaged,the shear strength of the old clay is greatly reduced. The strength reduction rate decreases correspondingly with the increase of the confining pressure,dynamic stress ratio and the number of cycles. The correlation of the old clay strength weakening model obtained with empirical formula is fairly high. The weakening mechanism of the strength of the old clay is further obtained.
引文
Ai C J,Tang H M,Luo H M,et al.2006.Research on the Deformation parameter and bearing performance of paleo-clay in Qingshan area of Wuhan[J].China Rural Water and Hydropower,(8):72-74,77.
Chen Y P,Huang B,Chen Y M.2005.Deformation and strength of structural soft clay under cyclic loading[J].Chinese Journal of Geotechnical Engineering,27(9):1065-1071.
Fan S K.2006.A discussion on karst collapse in Wuhan(Hubei)[J].Resources Environment&Engineering,20(S1):608-616.
Ge S P,Yao X J.2015.Response characteristics of pore pressure in soils nearby metro tunnel due to train vibration loading[J].Journal of Engineering Geology,23(6):1093-1099.
Gu Z H.2007.The excess pore-water pressure model of anisotropic consolidated saturated clay under cyclic loading[J].Chinese Journal of Underground Space and Engineering,3(4):776-780,786.
Li F.2004.The geological characteristic of old clay in Dongxi Lake in Wuhan[J].Soil Engineering and Foundation,18(3):55-56.
Luo X J.2013.Features of the shallow karst development and control of karst collapse in Wuhan[J].Carsologica Sinica,32(4):419-432.
Mao X P,Wu C L,Shi X M.2016.In-situ investigation on causes of road surface sinking at Haitai district of Tianjin hi-tech industrial park[J].Journal of Engineering Geology,24(2):299-308.
Tang H M,Zhou Y T,Chen H K,et al.2015.Stability analysis for wedge rockmass of underground cavities under dynamic load[J].Journal of Engineering Geology,23(3):485-490.
Wang C Y,Wang J Y.2007.The pattern of soil nail wall destroying in old clay area of Wuhan and prevention measures[J].Journal of Hubei University of Technology,22(2):50-53.
Wang S Y,Lou Z G.2000.The degradation of undrained shear strength of undisturbed and remolded marine clay after cyclic loading[J].Rock and Soil Mechanics,21(1):20-24.
Wang Y Z,Yan Z.2015a.Research on and application of undrained strength softening model of Tianjin soft clay under cyclic loading[J].Journal of Tianjin University(Science and Technology),48(4):347-354.
Wang Y Z,Yang P B,Sun X P,et al.2015b.Strength weakening of soft clay under cyclic loading and its dynamic calculation[J].Chinese Journal of Geotechnical Engineering,37(5):821-828.
Wu M Z,Zhou H,Chen Z C.1998.Test analysis of degradation behavior of saturated soft clay after cyclic loading[J].Journal of Tongji University,26(3):274-278.
Xu C J,Zhou H B.1998.Pore pressure increase model of saturated soft clay under undrained cyclic load[J].Site Investigation Science and Technology,(1):3-7.
Yan M C,Wang G Q,Li B S.2001.Geological Hazards and Their Countermeasures in the Land along the Guangdong Coast[J].Geography and Territorial Research,17(4):85-90.
Yasuhara K,Hirao K,Hyde A F L.1992.Effects of cyclic loading on undrained strength and compressibility of clay[J].Soils and Foundations,32(1):100-116.
Zhang K L,Tao Z Y.1994.The prediction of pore pressure of saturated clay under cyclic loading[J].Rock and Soil Mechanics,15(3):9-17.
Zhao C Y,Zhou S H,Zhuang L.2012.Cyclic accumulative pore pressure model of sofe clay in the Shanghai region[J].Journal of the China Railway Society,(1):77-82.
Zhou J,Gong X N.2001.Strain degradation of saturated clay under cyclic loading[J].Canadian Geotechnical Journal,38(1):208-212.
Zhou J.1998.Research on character of saturated soft clay under cyclic loading[D].Hangzhou:Zhejiang University.
Zhou X Q,Zhang Y Q,Chen M C,et al.2014.Application of H-shaped pile toe of square piles in old clay in Zhangjiang area[J].Coastal Engineering,33(2):20-26.
艾传井,唐辉明,罗红明,等.2006.武汉市青山地区老黏土的变形参数及承载性能研究[J].中国农村水利水电,(8):72-74,77.
陈颖平,黄博,陈云敏.2005.循环荷载作用下结构性软黏土的变形和强度特性[J].岩土工程学报,27(9):1065-1071.
范士凯.2006.武汉(湖北)地区岩溶地面塌陷[J].资源环境与工程,20(S1):608-616.
葛世平,姚湘静.2015.地铁振动荷载下隧道周边土体孔压响应特征研究[J].工程地质学报,23(6):1093-1099.
顾中华.2007.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,3(4):776-780,786.
李芳.2004.武汉市东西湖区老黏土的工程地质特性浅析[J].土工基础,18(3):55-56.
罗小杰.2013.武汉地区浅层岩溶发育特征与岩溶塌陷灾害防治[J].中国岩溶,32(4):419-432.
毛小平,吴冲龙,师学明.2016.天津高新技术产业园区海泰小区路面塌陷成因[J].工程地质学报,24(2):299-308.
唐红梅,周云涛,陈洪凯,等.2015.动荷载作用下地下洞室楔形体稳定性分析[J].工程地质学报,23(3):485-490.
王翠英,王家阳.2007.武汉老黏土地区土钉墙破坏形式及其防治措施[J].湖北工业大学学报,22(2):50-53.
王淑云,楼志刚.2000.原状和重塑海洋黏土经历动载后的静强度衰减[J].岩土力学,21(1):20-24.
王元战,焉振.2015a.循环荷载下天津软黏土不排水强度弱化模型研究及应用[J].天津大学学报(自然科学与工程技术版),48(4):347-354.
王元战,杨攀博,孙熙平,等.2015b.循环荷载下软黏土强度弱化研究及其动力计算应用[J].岩土工程学报,37(5):821-828.
吴明战,周洪波,陈竹昌.1998.循环加载后饱和软黏土退化性状的试验研究[J].同济大学学报,26(3):274-278.
许才军,周红波.1998.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,(1):3-7.
闫满存,王光谦,李保生.2001.广东沿海陆地地质灾害及其防治对策[J].地理学与国土研究,17(4):85-90.
章克凌,陶振宇.1994.饱和黏土在循环荷载作用下的孔压预测[J].岩土力学,15(3):9-17.
赵春彦,周顺华,庄丽.2012.上海地区软土的循环累积孔压模型[J].铁道学报,(1):77-82.
周建.1998.循环荷载作用下饱和软黏土特性研究[D].杭州:浙江大学.
周鑫强,张永强,陈木灿,等.2014.方桩H型桩尖在湛江地区老黏土中的应用[J].海岸工程,33(2):20-26.
Chen Y P,Huang B,Chen Y M.2005.Deformation and strength of structural soft clay under cyclic loading[J].Chinese Journal of Geotechnical Engineering,27(9):1065-1071.
Fan S K.2006.A discussion on karst collapse in Wuhan(Hubei)[J].Resources Environment&Engineering,20(S1):608-616.
Ge S P,Yao X J.2015.Response characteristics of pore pressure in soils nearby metro tunnel due to train vibration loading[J].Journal of Engineering Geology,23(6):1093-1099.
Gu Z H.2007.The excess pore-water pressure model of anisotropic consolidated saturated clay under cyclic loading[J].Chinese Journal of Underground Space and Engineering,3(4):776-780,786.
Li F.2004.The geological characteristic of old clay in Dongxi Lake in Wuhan[J].Soil Engineering and Foundation,18(3):55-56.
Luo X J.2013.Features of the shallow karst development and control of karst collapse in Wuhan[J].Carsologica Sinica,32(4):419-432.
Mao X P,Wu C L,Shi X M.2016.In-situ investigation on causes of road surface sinking at Haitai district of Tianjin hi-tech industrial park[J].Journal of Engineering Geology,24(2):299-308.
Tang H M,Zhou Y T,Chen H K,et al.2015.Stability analysis for wedge rockmass of underground cavities under dynamic load[J].Journal of Engineering Geology,23(3):485-490.
Wang C Y,Wang J Y.2007.The pattern of soil nail wall destroying in old clay area of Wuhan and prevention measures[J].Journal of Hubei University of Technology,22(2):50-53.
Wang S Y,Lou Z G.2000.The degradation of undrained shear strength of undisturbed and remolded marine clay after cyclic loading[J].Rock and Soil Mechanics,21(1):20-24.
Wang Y Z,Yan Z.2015a.Research on and application of undrained strength softening model of Tianjin soft clay under cyclic loading[J].Journal of Tianjin University(Science and Technology),48(4):347-354.
Wang Y Z,Yang P B,Sun X P,et al.2015b.Strength weakening of soft clay under cyclic loading and its dynamic calculation[J].Chinese Journal of Geotechnical Engineering,37(5):821-828.
Wu M Z,Zhou H,Chen Z C.1998.Test analysis of degradation behavior of saturated soft clay after cyclic loading[J].Journal of Tongji University,26(3):274-278.
Xu C J,Zhou H B.1998.Pore pressure increase model of saturated soft clay under undrained cyclic load[J].Site Investigation Science and Technology,(1):3-7.
Yan M C,Wang G Q,Li B S.2001.Geological Hazards and Their Countermeasures in the Land along the Guangdong Coast[J].Geography and Territorial Research,17(4):85-90.
Yasuhara K,Hirao K,Hyde A F L.1992.Effects of cyclic loading on undrained strength and compressibility of clay[J].Soils and Foundations,32(1):100-116.
Zhang K L,Tao Z Y.1994.The prediction of pore pressure of saturated clay under cyclic loading[J].Rock and Soil Mechanics,15(3):9-17.
Zhao C Y,Zhou S H,Zhuang L.2012.Cyclic accumulative pore pressure model of sofe clay in the Shanghai region[J].Journal of the China Railway Society,(1):77-82.
Zhou J,Gong X N.2001.Strain degradation of saturated clay under cyclic loading[J].Canadian Geotechnical Journal,38(1):208-212.
Zhou J.1998.Research on character of saturated soft clay under cyclic loading[D].Hangzhou:Zhejiang University.
Zhou X Q,Zhang Y Q,Chen M C,et al.2014.Application of H-shaped pile toe of square piles in old clay in Zhangjiang area[J].Coastal Engineering,33(2):20-26.
艾传井,唐辉明,罗红明,等.2006.武汉市青山地区老黏土的变形参数及承载性能研究[J].中国农村水利水电,(8):72-74,77.
陈颖平,黄博,陈云敏.2005.循环荷载作用下结构性软黏土的变形和强度特性[J].岩土工程学报,27(9):1065-1071.
范士凯.2006.武汉(湖北)地区岩溶地面塌陷[J].资源环境与工程,20(S1):608-616.
葛世平,姚湘静.2015.地铁振动荷载下隧道周边土体孔压响应特征研究[J].工程地质学报,23(6):1093-1099.
顾中华.2007.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,3(4):776-780,786.
李芳.2004.武汉市东西湖区老黏土的工程地质特性浅析[J].土工基础,18(3):55-56.
罗小杰.2013.武汉地区浅层岩溶发育特征与岩溶塌陷灾害防治[J].中国岩溶,32(4):419-432.
毛小平,吴冲龙,师学明.2016.天津高新技术产业园区海泰小区路面塌陷成因[J].工程地质学报,24(2):299-308.
唐红梅,周云涛,陈洪凯,等.2015.动荷载作用下地下洞室楔形体稳定性分析[J].工程地质学报,23(3):485-490.
王翠英,王家阳.2007.武汉老黏土地区土钉墙破坏形式及其防治措施[J].湖北工业大学学报,22(2):50-53.
王淑云,楼志刚.2000.原状和重塑海洋黏土经历动载后的静强度衰减[J].岩土力学,21(1):20-24.
王元战,焉振.2015a.循环荷载下天津软黏土不排水强度弱化模型研究及应用[J].天津大学学报(自然科学与工程技术版),48(4):347-354.
王元战,杨攀博,孙熙平,等.2015b.循环荷载下软黏土强度弱化研究及其动力计算应用[J].岩土工程学报,37(5):821-828.
吴明战,周洪波,陈竹昌.1998.循环加载后饱和软黏土退化性状的试验研究[J].同济大学学报,26(3):274-278.
许才军,周红波.1998.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,(1):3-7.
闫满存,王光谦,李保生.2001.广东沿海陆地地质灾害及其防治对策[J].地理学与国土研究,17(4):85-90.
章克凌,陶振宇.1994.饱和黏土在循环荷载作用下的孔压预测[J].岩土力学,15(3):9-17.
赵春彦,周顺华,庄丽.2012.上海地区软土的循环累积孔压模型[J].铁道学报,(1):77-82.
周建.1998.循环荷载作用下饱和软黏土特性研究[D].杭州:浙江大学.
周鑫强,张永强,陈木灿,等.2014.方桩H型桩尖在湛江地区老黏土中的应用[J].海岸工程,33(2):20-26.