基于极限分析上限法,分析了基坑底部刚塑性三角形楔体ABC,BDE和对数螺旋线受剪区BCD 3个区域的速度场,建立了基坑底部塑性区的虚功率方程,据此推导出基坑抗隆起稳定安全性要求下的支护入土深度上限解和支护入土深度为t时的基坑抗隆起稳定性安全系数k。经工程实例验证可知,基坑支护入土深度上限解和抗隆起稳定性安全系数计算式合理,可为将来同类型的基坑支护入土深度计算提供参考和经验,并可进一步完善和提高基坑底部土体稳定的准确率。
Abstract
According to upper bound theorem of the limit analysis method, we analyzed the velocity field at the bottom of active slip zone ABC and transition zone BCD and passive slip zone BDE in a foundation pit. Virtual work-rate equation of plastic area at the bottom of the foundation pit was established. On this basis, the upper-bound solution to the depth of support excavations which meets the requirement of stability against upheaval was induced, and the stability safety factor k was solved when the support depth t was given. Engineering examples verified that the upper-bound solution and the formula of stability safety factor k are rational. The results could provide reference for the calculation of support depth in similar foundation pits, and improve the correctness of bottom soil stability in foundation pit.
关键词
基坑支护 /
入土深度 /
极限分析法 /
上限解 /
安全系数
Key words
excavation support /
support depth /
limit analysis method /
upper-bound solution /
safety factor
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参考文献
[1] 秦会来,陈祖煜,刘立鹏. 基于上限理论的软土基坑抗隆起稳定分析方法[J]. 岩土工程学报,2012,34(9):1611-1619. (QIN Hui-lai,CHEN Zu-yu,LIU Li-peng. Basal Stability Analysis for Excavations in Soft Clay Based on Upper Bound Method[J]. Chinese Journal of Geotechnical Engineering,2012,34(9):1611-1619. (in Chinese))
[2] 陈 刚,阮 澍,李九思. 软土基坑喷锚支护设计与实例分析[J]. 岩土力学,2002,23(增1):161-164. (CHEN Gang,RUAN Shu,LI Jiu-si. Design and Analysis of Shotcreting and Anchoring Support Applied to Foundation Pit in Soft Soil[J]. Rock and Soil Mechanics,2002,23(Sup.1):161-164. (in Chinese))
[3] 秦会来,黄茂松,王卫东. 非均质软土基坑抗隆起稳定性的极限分析方法[J]. 岩土力学,2008,29(10):2719-2724. (QIN Hui-lai,HUANG Mao-song,WANG Wei-dong. Limit Analysis Method for Basal Stability of Braced Excavation Against Upheaval in Heterogeneous Soft Clay[J]. Rock and Soil Mechanics,2008,29(10):2719-2724.(in Chinese))
[4] 张耀东,龚晓南. 软土基坑抗隆起稳定性计算的改进[J]. 岩土工程学报,2006,28(增1):1378-1382.(ZHANG Yao-dong,GONG Xiao-nan. Improvement on Basal Heave Stability Analysis for Excavations in Soft Clay[J]. Chinese Journal of Geotechnical Engineering,2006,28(Sup.1):1378-1382.(in Chinese))
[5] 李镜培,唐 耀,张 飞. 考虑支护结构的软土基坑抗隆起稳定上限分析[J]. 地下空间与工程学报,2011,7(5):1007-1012.(LI Jing-pei,TANG Yao,ZHANG Fei. Analysis of Stability Against Upheaval of Excavation by Upper Bound Method Considering the Retaining[J]. Chinese Journal of Underground Space and Engineering,2011,7(5):1007-1012.(in Chinese))
[6] SHIRAW J,WEN D,NADARAJAH P,et al. Design Issues Related to Jet Grouted Piles at Base of Excavations[C]//Proceedings of Tunnels and Underground Structures. Singapore:A.A.Balkema,2000:639-645.(in Chinese))
[7] 张玉成,杨光华,钟志辉,等. 软土基坑设计若干关键问题探讨及基坑设计实例应用分析[J]. 岩石力学与工程学报,2012,31(11):2334-2343.(ZHANG Yu-cheng,YANG Guang-hua,ZHONG Zhi-hui,et al. Discussion on Some Key Problems in Soft Soil Foundation Pit and Application Analysis of Design Example[J]. Chinese Journal of Rock Mechanics and Engineering,2012,31(11):2334-2343.(in Chinese))
[8] 刘 润,闫 玥,闫澍旺.支撑位置对基坑整体稳定性的影响[J]. 岩石力学与工程学报,2006, 25(1):174-178. (LIU Run, YAN Yue, YAN Shu-wang. Stability Analysis of Foundation Pit with Position Change of Braces[J]. Chinese Journal of Rock Mechanics and Engineering,2006, 25(1):174-178.(in Chinese))
[9] 陈惠发. 极限分析与土体塑性[M]. 詹世斌译. 北京:人民交通出版社, 1995.(CHEN Hui-fa. Limit Analysis and Soil Plasticity[M]. Translated by ZHAN Shi-bin.
Beijing:China Communications Press,1995.(in Chinese))
[10]龚晓南. 土塑性力学[M]. 杭州:浙江大学出版社,1997:319-320.(GONG Xiao-nan. Soil Plasticity[M]. Hangzhou:Zhejiang University Press,1997:319-320. (in Chinese))
[11]赵永清. 基坑支护结构土压力计算及坑底稳定性研究[D]. 湘潭:湖南科技大学,2014:47. (ZHAO Yong-qing. Calculation of Earth Pressure and Stability of Foundation Pit’s Retaining Structure[D]. Xiangtan:Hunan University of Science and Technology,2014: 47. (in Chinese))
基金
江西省科技计划项目(20123BBG70180);江西科技学院规划建设学科项目(结构工程);江西科技学院自然科学研究项目(ZR14YB08)
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