黄土湿陷性分布不连续对湿陷变形的影响研究
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摘要
分析导致湿陷量计算值与实测值差异的原因对黄土湿陷性的准确评价具有重要作用,目前相关研究的深度和系统性还不足。以西安黄土塬区的黄土现场试坑浸水试验为依托,采用数值计算手段,对湿陷土与非湿陷土不同比例、排列方式和湿陷程度下土体的湿陷变形特征进行了对比研究,揭示了黄土中湿陷土分布不连续对湿陷变形产生的抑制作用是导致湿陷量计算值和实测值差异的重要原因之一。当黄土体中湿陷土单元和非湿陷土单元分布越杂乱,非湿陷土单元所占的比例越高时,这种抑制作用越明显;而湿陷土单元的湿陷程度对抑制作用的影响相对较弱。在计算湿陷量时,应考虑黄土湿陷性不连续效应的影响,并在工程实践中逐渐积累反映这种效应影响的经验数据。
Investigating the difference between the calculated and measured values of the collapsible settlement is useful and necessary to accurately evaluate the loess collapsibility. Although the difference has been noted by many researches, it has not yet been examined deeply and systematically. Based on the results of two field loess immersion tests in Xi'an loess tableland area, the numerical method is used to compare the collapsible deformations of loess foundation with different proportions and arrangements of collapsible and non-collapsible soils as well as with different collapsible degrees of collapsible soils. The results reveal that the inhibition effect on collapsible deformation, which is caused by the discontinuous distribution of collapsible loess, is one of the main reasons for the discrepancy between the calculated and measured values of the collapsible settlement. In addition, this inhibition effect is more significant for the cases with more random distribution of collapsible and non-collapsible soils, or with higher proportion of non-collapsible soils. Through comparison, the impact on the inhibition effect caused by the collapsible degree of collapsible soils is not very strong. The inhibition effect should be taken into account in calculating the collapsible deformation, and the related data should be collected and summarized in future engineering practice.
Investigating the difference between the calculated and measured values of the collapsible settlement is useful and necessary to accurately evaluate the loess collapsibility. Although the difference has been noted by many researches, it has not yet been examined deeply and systematically. Based on the results of two field loess immersion tests in Xi'an loess tableland area, the numerical method is used to compare the collapsible deformations of loess foundation with different proportions and arrangements of collapsible and non-collapsible soils as well as with different collapsible degrees of collapsible soils. The results reveal that the inhibition effect on collapsible deformation, which is caused by the discontinuous distribution of collapsible loess, is one of the main reasons for the discrepancy between the calculated and measured values of the collapsible settlement. In addition, this inhibition effect is more significant for the cases with more random distribution of collapsible and non-collapsible soils, or with higher proportion of non-collapsible soils. Through comparison, the impact on the inhibition effect caused by the collapsible degree of collapsible soils is not very strong. The inhibition effect should be taken into account in calculating the collapsible deformation, and the related data should be collected and summarized in future engineering practice.
引文
[1]刘祖典.黄土力学与工程[M].西安:陕西科学技术出版社,1997.(LIU Zu-dian.Mechanics and engineering of loess[M].Xi'an:Shaanxi Science and Technology Press,1997.(in Chinese))
[2]GB 50025—2004湿陷性黄土地区建筑规范[S].2004.(GB50025—2004 Code for building construction in collapsible loess regions[S].2004.(in Chinese))
[3]李大展,何颐华,隋国秀.Q2黄土大面积浸水试验研究[J].岩土工程学报,1993,15(2):1–11.(LI Da-zhan,HE Yi-hua,SUI Guo-xiu.Study and test on immersion of Q2 loess in large area[J].Chinese Journal of Geotechnical Engineering,1993,15(2):1–11.(in Chinese))
[4]黄雪峰,陈正汉,哈双,等.大厚度自重湿陷性黄土场地湿陷变形特征的大型现场浸水试验研究[J].岩土工程学报,2006,28(3):382–389.(HUANG Xue-feng,CHEN Zheng-han,HA Shuang,et al.Large area field immersion tests on characteristics of deformation of self weight collapse loess under overburden pressure[J].Chinese Journal of Geotechnical Engineering,2006,28(3):382–389.(in Chinese))
[5]任海波.某黄土场地试坑浸水试验[J].陕西建筑,2008(158):29–30.(REN Hai-bo.An in-site immersion test of loess site[J].Shaanxi Architecture,2008(158):29–30.(in Chinese))
[6]马侃彦,张继文,刘争宏,等.自重湿陷性黄土场地的试坑浸水试验[J].勘察科学技术,2009(5):33–36.(MA Kan-yan,ZHANG Ji-wen,LIU Zheng-hong,et al.Immersion test of test pit at self weight collapse loess site[J].Site Investigation Science and Technology,2009(5):33–36.(in Chinese))
[7]杨庆义.湿陷性黄土现场浸水试验研究[J].水电能源科学,2011,29(6):58–60.(YANG Qing-yi.Field immersion tests of collapsible loess[J].Water Resources and Power,2011,29(6):58–60.(in Chinese))
[8]王小军,米维军,熊治文,等.郑西客运专线黄土地基湿陷性现场浸水试验研究[J].铁道学报,2012,34(1):83–90.(WANG Xiao-jun,MI Wei-jun,XIONG Zhi-wen,et al.Water immersion field tests of collapsibility of loess foundation of Zhengzhou-Xi'an passenger dedicated line[J].Journal of the China Railway Society,2012,34(1):83–90.(in Chinese))
[9]石怀清,张继文,王东红.西安塬区中更新世Q2黄土场地浸水试验研究[J].岩土工程技术,2012,26(4):177–180.(SHI Huai-qing,ZHANG Ji-wen,WANG Dong-hong.In-situ tests and analysis of Medio Pleistocene Q2 loess at Xi’an Tableland[J].Geotechnical Engineering Technique,2012,26(4):177–180.(in Chinese))
[10]黄雪峰,杨校辉,朱彦鹏,等.大厚度自重湿陷性黄土现场浸水和地基处理深度综合试验研究[C]//第十二届全国地基处理学术讨论会论文集.昆明:云南人民出版社,2012:31–43.(HUANG Xue-feng,YANG Xiao-hui,ZHU Yan-peng,et al.Combined experimental study of loess immersion test and foundation treatment thickness for collapse loess with lager thickness[C]//The 12th China Symposium on Foundation Treatment.Kunming:Yunnan People's Publishing House,2012:31–43.(in Chinese))
[11]王延辉,张希宏,袁勤刚.大厚度黄土自重湿陷性试验分析研究[J].勘察科学技术,2013(3):5–8.(WANG Yan-hui,ZHANG Xi-hong,YUAN Qin-gang.Analysis and study on self-weight collapsible test of big thickness loess under overburden press[J].Site Investigation Science and Technology,2013(3):5–8.(in Chinese))
[12]黄雪峰,杨校辉.湿陷性黄土现场浸水试验研究进展[J].岩土力学,2013,34(增刊2):222–228.(HUANG Xue-feng,YANG Xiao-hui.A study progress on in-situ soaking test on collapsible loess[J].Rock and Soil Mechanics,2013,34(S2):222–228.(in Chinese))
[13]武小鹏,楚华栋,屈耀辉,等.自重湿陷性黄土下限深度判定方法探讨[J].西北地震学报,2011,33(增刊):218–222.(WU Xiao-peng,CHU Hua-dong,QU Yao-hui,et al.Discussion on judging methods for the maximum depth of collapsible loess under overburden pressure[J].Northwestern Seismological Journal,2011,33(S0):218–222.(in Chinese))
[14]彭建兵.西安地裂缝灾害[M].北京:科学出版社,2012.(PENG Jian-bing.Ground fissures disaster in Xi'an[M].Beijing:Science Press,2012.(in Chinese))
[15]陈正汉,刘祖典.黄土的湿陷变形机理[J].岩土工程学报,1986,8(2):1–12.(CHEN Zheng-han,LIU Zu-dian.Mechanism of collapse deformation of loess[J].Chinese Journal of Geotechnical Engineering,1986,8(2):1–12.(in Chinese))
[16]高国瑞.黄土湿陷变形的结构理论[J].岩土工程学报,1990,12(4):1–10.(GAO Guo-rui.A structure theory for collapsing deformation of loess soils[J].Chinese Journal of Geotechnical Engineering,1990,12(4):1–10.(in Chinese))
[2]GB 50025—2004湿陷性黄土地区建筑规范[S].2004.(GB50025—2004 Code for building construction in collapsible loess regions[S].2004.(in Chinese))
[3]李大展,何颐华,隋国秀.Q2黄土大面积浸水试验研究[J].岩土工程学报,1993,15(2):1–11.(LI Da-zhan,HE Yi-hua,SUI Guo-xiu.Study and test on immersion of Q2 loess in large area[J].Chinese Journal of Geotechnical Engineering,1993,15(2):1–11.(in Chinese))
[4]黄雪峰,陈正汉,哈双,等.大厚度自重湿陷性黄土场地湿陷变形特征的大型现场浸水试验研究[J].岩土工程学报,2006,28(3):382–389.(HUANG Xue-feng,CHEN Zheng-han,HA Shuang,et al.Large area field immersion tests on characteristics of deformation of self weight collapse loess under overburden pressure[J].Chinese Journal of Geotechnical Engineering,2006,28(3):382–389.(in Chinese))
[5]任海波.某黄土场地试坑浸水试验[J].陕西建筑,2008(158):29–30.(REN Hai-bo.An in-site immersion test of loess site[J].Shaanxi Architecture,2008(158):29–30.(in Chinese))
[6]马侃彦,张继文,刘争宏,等.自重湿陷性黄土场地的试坑浸水试验[J].勘察科学技术,2009(5):33–36.(MA Kan-yan,ZHANG Ji-wen,LIU Zheng-hong,et al.Immersion test of test pit at self weight collapse loess site[J].Site Investigation Science and Technology,2009(5):33–36.(in Chinese))
[7]杨庆义.湿陷性黄土现场浸水试验研究[J].水电能源科学,2011,29(6):58–60.(YANG Qing-yi.Field immersion tests of collapsible loess[J].Water Resources and Power,2011,29(6):58–60.(in Chinese))
[8]王小军,米维军,熊治文,等.郑西客运专线黄土地基湿陷性现场浸水试验研究[J].铁道学报,2012,34(1):83–90.(WANG Xiao-jun,MI Wei-jun,XIONG Zhi-wen,et al.Water immersion field tests of collapsibility of loess foundation of Zhengzhou-Xi'an passenger dedicated line[J].Journal of the China Railway Society,2012,34(1):83–90.(in Chinese))
[9]石怀清,张继文,王东红.西安塬区中更新世Q2黄土场地浸水试验研究[J].岩土工程技术,2012,26(4):177–180.(SHI Huai-qing,ZHANG Ji-wen,WANG Dong-hong.In-situ tests and analysis of Medio Pleistocene Q2 loess at Xi’an Tableland[J].Geotechnical Engineering Technique,2012,26(4):177–180.(in Chinese))
[10]黄雪峰,杨校辉,朱彦鹏,等.大厚度自重湿陷性黄土现场浸水和地基处理深度综合试验研究[C]//第十二届全国地基处理学术讨论会论文集.昆明:云南人民出版社,2012:31–43.(HUANG Xue-feng,YANG Xiao-hui,ZHU Yan-peng,et al.Combined experimental study of loess immersion test and foundation treatment thickness for collapse loess with lager thickness[C]//The 12th China Symposium on Foundation Treatment.Kunming:Yunnan People's Publishing House,2012:31–43.(in Chinese))
[11]王延辉,张希宏,袁勤刚.大厚度黄土自重湿陷性试验分析研究[J].勘察科学技术,2013(3):5–8.(WANG Yan-hui,ZHANG Xi-hong,YUAN Qin-gang.Analysis and study on self-weight collapsible test of big thickness loess under overburden press[J].Site Investigation Science and Technology,2013(3):5–8.(in Chinese))
[12]黄雪峰,杨校辉.湿陷性黄土现场浸水试验研究进展[J].岩土力学,2013,34(增刊2):222–228.(HUANG Xue-feng,YANG Xiao-hui.A study progress on in-situ soaking test on collapsible loess[J].Rock and Soil Mechanics,2013,34(S2):222–228.(in Chinese))
[13]武小鹏,楚华栋,屈耀辉,等.自重湿陷性黄土下限深度判定方法探讨[J].西北地震学报,2011,33(增刊):218–222.(WU Xiao-peng,CHU Hua-dong,QU Yao-hui,et al.Discussion on judging methods for the maximum depth of collapsible loess under overburden pressure[J].Northwestern Seismological Journal,2011,33(S0):218–222.(in Chinese))
[14]彭建兵.西安地裂缝灾害[M].北京:科学出版社,2012.(PENG Jian-bing.Ground fissures disaster in Xi'an[M].Beijing:Science Press,2012.(in Chinese))
[15]陈正汉,刘祖典.黄土的湿陷变形机理[J].岩土工程学报,1986,8(2):1–12.(CHEN Zheng-han,LIU Zu-dian.Mechanism of collapse deformation of loess[J].Chinese Journal of Geotechnical Engineering,1986,8(2):1–12.(in Chinese))
[16]高国瑞.黄土湿陷变形的结构理论[J].岩土工程学报,1990,12(4):1–10.(GAO Guo-rui.A structure theory for collapsing deformation of loess soils[J].Chinese Journal of Geotechnical Engineering,1990,12(4):1–10.(in Chinese))
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