统一的地基沉降速率分析方法
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摘要
为了确定堆载预压法处理公路路基的卸载时机,提出了一类适用于欠载、等载和超载不同预压方式的沉降率分析通用表达式.然后,基于线性压缩的Terzaghi一维固结理论,提出了一种针对超载预压卸载时刻地基超静孔隙水压力回弹区和压缩区的分析方法,引入了地基残余沉降修正系数,推导出适用于欠载、超载不同预压方式的地基附加沉降量计算方法,进而得到基于线性沉降率的统一沉降率模型.结果表明:同等工后沉降下,欠载预压沉降率相对等载预压降低,预压时间延长;超载预压沉降率相对等载预压增大,预压时间缩短.最后,揭示了不同水平工后沉降和软土层厚度等对欠、超载预压沉降率分析的影响机制.
To decide the unloading time of expressway treated by the preloading method,a simple generalized expression of the ground settlement rate applied to insufficient-load preloading,equal-load preloading and surcharge preloading is presented.Then,based on the Terzaghi 1D consolidation theory of linear compressibility,a rational method for regionalization of recompression and compression in the distribution of the excess pore-water pressure under overloading-unloading is presented.With the introduction of the modified coefficient of the ground residual settlement,a calculation method of the ground additional settlement applied to insufficient-load and surcharge preloading is described.And an unified linear settlement rate model under linear settlement rate is obtained.The results show that with the same post-construction settlement,the settlement rate of insufficient-load preloading is lower than that of equal-load preloading;the time of insufficient-load preloading is longer than that of equal-load preloading;the settlement rate of surcharge preloading is higher than that of equal-load preloading;the time of surcharge preloading is shorter than that of equal-load preloading.Finally,the influence mechanism of different post-construction settlement and soft soil thickness on the settlement rate of insufficient-load preloading and surcharge preloading is analyzed.
To decide the unloading time of expressway treated by the preloading method,a simple generalized expression of the ground settlement rate applied to insufficient-load preloading,equal-load preloading and surcharge preloading is presented.Then,based on the Terzaghi 1D consolidation theory of linear compressibility,a rational method for regionalization of recompression and compression in the distribution of the excess pore-water pressure under overloading-unloading is presented.With the introduction of the modified coefficient of the ground residual settlement,a calculation method of the ground additional settlement applied to insufficient-load and surcharge preloading is described.And an unified linear settlement rate model under linear settlement rate is obtained.The results show that with the same post-construction settlement,the settlement rate of insufficient-load preloading is lower than that of equal-load preloading;the time of insufficient-load preloading is longer than that of equal-load preloading;the settlement rate of surcharge preloading is higher than that of equal-load preloading;the time of surcharge preloading is shorter than that of equal-load preloading.Finally,the influence mechanism of different post-construction settlement and soft soil thickness on the settlement rate of insufficient-load preloading and surcharge preloading is analyzed.
引文
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[7]杨涛,李国维.公路软基超载预压卸荷时间确定的沉降速率法研究[J].岩土工程学报,2006,28(11):1942-1946.Yang Tao,Li Guow ei.Settlement rate method for determining surcharge removal time for embankment onsoft ground[J].Chinese Journal of G eotechnical Engineering,2006,28(11):1942-1946.(in Chinese)
[8]杨涛,周有成,李聪.公路软基超载预压卸荷沉降速率标准研究[J].工业建筑,2009,39(12):70-73.Yang Tao,Zhou Youcheng,Li Cong.Study on the settlement rate standard for determining the surcharge removal time for embankment on soft ground[J].Industrial Construction,2009,39(12):70-73.(in Chinese)
[9]潘秋元,朱向荣,谢康和,等.关于砂井地基超载预压的若干问题[J].岩土工程学报,1991,13(2):1-12.Pan Qiuyuan,Zhu Xiangrong,Xie Kanghe,et al.Some aspects of surcharge precompression on ground w ith sand drains[J].Chinese Journal of G eotechnical Engineering,1991,13(2):1-12.(in Chinese)
[10]张光永.堆载预压法的卸载比及卸载控制[J].华中科技大学学报:城市科学版,2003,20(4):37-39.Zhang Guangyong.Study on surcharge ratio and unloading control of surcharge precompression[J].Journal of Huazhong University of Science and Technology:Urban Science Edition,2003,20(4):37-39.(in Chinese)
[11]刘吉福.堆载预压法处理高速公路路基的卸载时机研究[D].广州:华南理工大学土木与交通学院,2010.
[12]中华人民共和国住房和城乡建设部.GB 50007—2002建筑地基基础设计规范[S].北京:中国建筑工业出版社,2002.
[2]羊晔,刘松玉,邓永锋,等.软土地基过渡段差异沉降控制标准[J].东南大学学报:自然科学版,2008,38(5):834-838.Yang Ye,Liu Songyu,Deng Yongfeng,et al.Differ-ential settlement controlling criteria of highw ay transitionsections on soft soil foundation[J].Journal of South-east University:Natural Science Edition,2008,38(5):834-838.(in Chinese)
[3]刘吉福,莫海鸿.对沉降速率法确定卸载时机的认识[J].岩石力学与工程学报,2007,26(S1):3065-3072.Liu Jifu,Mo Haihong.Understanding of determining of unloading time using settlement velocity method[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(S1):3065-3072.(in Chinese)
[4]张长生,张伯友,刘国楠.应用沉降速率推算剩余沉降及卸载时间[J].地球科学与环境学报,2005,27(4):28-32.Zhang Changsheng,Zhang Boyou,Liu Guonan.Application of settlement velocity to calculate residual settlement and unloading time[J].Journal of Earth Sciences and Environment,2005,27(4):28-32.(in Chinese)
[5]曹国强,张仪萍,张土乔,等.地基沉降速率与沉降的关系研究及其应用[J].岩土力学,2003,24(3):467-470.Cao Guoqiang,Zhang Yiping,Zhang Tuqiao,et al.Relationship betw een settlement-velocity and settlement of ground and its applications[J].Rock and Soil Mechanics,2003,24(3):467-470.(in Chinese)
[6]陈道志,陈东升.软土路基超载设计与卸荷时机的确定[J].中南公路工程,2004,29(1):66-69.Chen Daozhi,Chen Dongsheng.Overload design and unload time determination of soil foundation for highw ays[J].Central South Highway Engineering,2004,29(1):66-69.(in Chinese)
[7]杨涛,李国维.公路软基超载预压卸荷时间确定的沉降速率法研究[J].岩土工程学报,2006,28(11):1942-1946.Yang Tao,Li Guow ei.Settlement rate method for determining surcharge removal time for embankment onsoft ground[J].Chinese Journal of G eotechnical Engineering,2006,28(11):1942-1946.(in Chinese)
[8]杨涛,周有成,李聪.公路软基超载预压卸荷沉降速率标准研究[J].工业建筑,2009,39(12):70-73.Yang Tao,Zhou Youcheng,Li Cong.Study on the settlement rate standard for determining the surcharge removal time for embankment on soft ground[J].Industrial Construction,2009,39(12):70-73.(in Chinese)
[9]潘秋元,朱向荣,谢康和,等.关于砂井地基超载预压的若干问题[J].岩土工程学报,1991,13(2):1-12.Pan Qiuyuan,Zhu Xiangrong,Xie Kanghe,et al.Some aspects of surcharge precompression on ground w ith sand drains[J].Chinese Journal of G eotechnical Engineering,1991,13(2):1-12.(in Chinese)
[10]张光永.堆载预压法的卸载比及卸载控制[J].华中科技大学学报:城市科学版,2003,20(4):37-39.Zhang Guangyong.Study on surcharge ratio and unloading control of surcharge precompression[J].Journal of Huazhong University of Science and Technology:Urban Science Edition,2003,20(4):37-39.(in Chinese)
[11]刘吉福.堆载预压法处理高速公路路基的卸载时机研究[D].广州:华南理工大学土木与交通学院,2010.
[12]中华人民共和国住房和城乡建设部.GB 50007—2002建筑地基基础设计规范[S].北京:中国建筑工业出版社,2002.