为分析加筋土结构设计目前大都采用的极限平衡理论的保守问题, 在介绍国际上若干现行规范要点的基础上, 以国内外若干工程的实测资料说明这种保守的程度。还对加筋土结构的破坏模式和稳定校核的内容作了叙述, 建议从筋材本身的安全与加筋土结构整体稳定2方面进行稳定计算, 认为复合滑动面可能是结构稳定安全系数最小的滑动面, 该滑动面可能穿过筋材并沿筋材表面滑动。目前常用的所谓“外部稳定校核”、“内部稳定校核”等分析方法, 不可能找到整个结构所有可能的滑动面。最后对加筋土结构的合理设计方法提出了建议, 认为对结构物的应力应变分析是设计的最基本、最有用的资料, 但极限状态下结构物性状也需掌握, 因此最合理的是采用有限元分析法和极限平衡分析法相结合的设计方法。
The design of reinforced soil structure is mostly based on the Limited Equilibrium Theory (LET), which is somewhat conservative. In this paper, the conservatism in several international design codes or design guidelines are analyzed, and field measurement data from well working reinforced soil structures are listed to verify the degree of conservatism. Moreover, the failure modes (patterns) and stability analysis scenario for reinforced structures are described. Stability calculation is recommended to be conducted in terms of the stability of reinforcement material itself and the overall stability of reinforced soil structure. It is emphasized that as not all of the possible failure mechanisms were found from internal or external stability analysis, analysis on the compound slide surface which has possibly the minimum stability coefficient is necessary. It means that the designer has to consider all failure mechanisms: the compound slip surface might slide across the reinforcement and/or slide along the geosynthetics at each layer. So the stability calculation for the whole structure needs to be conducted without any distinction of internal or external. Finally, a reasonable design method (FEM + LEM) for reinforced soil structures is recommended. Stress-strain analysis is the most fundamental and useful data for design, but the performance of structure in limit state should also be taken into consideration.
[1] BATHURST R J, ALLEN T M, WALTERS D L. Reinforcement Loads in Geosynthetic Walls and the Case for a New Working Stress Design Method[J]. Geotextiles & Geomembranes, 2005, 23(4): 287-322.
[2] CHRISTOPHER B R. USA Design Guidelines for Geosynthetic Reinforced Soil Walls: Slopes and Embankments[C]∥Proceedings of the 9th International Conference on Geosynthetics, Guaruja, Brazil, May 23-27, 2010: 237-241.
[3] TATSUOKA F. Introduction to Japanese Codes for Reinforced Soil Design[C]∥Proceedings of the 9th International Conference on Geosynthetics, Guaruja, Brazil, May 23-27, 2010: 247-258.
[4] EHRLICH M, BECKER L D B. Reinforced Soil Wall Measurements and Predictions[C]∥Proceedings of the 9th International Conference on Geosynthetics, Guaruja, Brazil, May 23-27, 2010: 547-562.
[5] BRU G. EBGEO 2010: Recommendation for Reinforcement with Geosynthetics[C]∥Proceedings of the 9th International Conference on Geosynthetics, Guaruja, Brazil, May 23-27, 2010: 233-236.
[6] JENNER C. British Standard Code of Practice: BS8006[C]∥Proceedings of the 9th International Conference on Geosynthetics, Guaruja, Brazil, May 23–27, 2010: 243-246.
[7] COMODROMOS E, PAPADOPOULOU M. Design of Pile Groups under Lateral Loading Using a New y-multipliers Method[C]∥Proceedings of the 9th International Conference on Testing and Design Methods for Deep Foundations, Kanazwa, Japan, September 18-20, 2012: 1835-1839.
[8] 包承纲.土工合成材料应用原理与工程实践[M].北京:中国水利水电出版社, 2008. (BAO Cheng-gang. Application Principle and Engineering Practice of Geosynthetic Materials[M]. Beijing: China Water Power Press, 2008. (in Chinese))
[9] BATHURST R J, ALLEN T M, HUANG B Q. Current Issues for the Internal Stability Design of Geosynthetic Reinforced Soil[C]∥Proceedings of the 9th International Conference on Geosynthetics, Guaruja, Brazil, May 23-27, 2010: 533-546.
[10]包承纲, 汪明元, 丁金华. 格栅加筋土工作机理的试验研究[J].长江科学院院报, 2013, (1):34-41.(BAO Cheng-gang, WANG Ming-yuan, DING Jin-hua. Experimental Investigation on Working Mechanism of Reinforced Soil with Geogrid[J]. Journal of Yangtze River Scientific Research Institute, 2013, (1): 34-41. (in Chinese))
[11]COMODROMOS E, PAPADOPOULOU M, KLIMIS N. Analysis and Design of Reinforced Embankments: Methodology, Implementation and Impact of Critical Parameters[C]∥Proceedings of the 9th International Conference on Geosynthetics, Guaruja, Brazil, May 23–27, 2010: 1715-1719.
[12]杨广庆, 张保俭, 周乔勇, 等.土工格栅加筋石灰土挡墙工程特性试验研究[C]∥土工合成材料加筋——机遇与挑战.北京:中国铁道出版社, 2009:277－284. (YANG Guang-qing, ZHANG Bao-jian, ZHOU Qiao-yong, et al. Experimental Investigation on Engineering Properties of a Rime-soil Retaining Wall Reinforced with Geogrid[C]∥Geosynthetic Reinforcement: Opportunities and Challenges, Beijing: China Railway Press, 2009: 277-284.(in Chinese))
[13]何其武, 陈丽丽, 王旭龙. 斜坡地基土工格栅加筋土高边坡现场试验研究[C]∥土工合成材料加筋——机遇与挑战.北京:中国铁道出版社, 2009:368-377. (HE Qi-wu, CHEN LI-li, WANG Xu-long. Field Experimental Investigation on a High Slope Based on a Tilt Foundation with Geogrid Reinforcement[C]∥Geosynthetic Reinforcement: Opportunities and Challenges, Beijing: China Railway Press, 2009: 368-377. (in Chinese))
[14]ASCHAUER F, WU W. Investigation of the Behavior of Geosynthetic/Soil Systems in Reinforced-Soil Structures[C]∥Proceedings of the 8th International Conference on Geosynthetics, Yokohama, Japan, September 18-22, 2006: 1049-1052.
[15]NANCEY A, ROSSI D, BOONS B. Survey of a Bridge Abutment Reinforced by Geosynthetics with Optic Sensors Integrated in Geotextile Strips[C]∥Proceedings of the 8th International Conference on Geosynthetics, Yokohama, Japan, September 18-22, 2006: 1071-1074.
[16]HERLE V. Prediction and Performance of Reinforced Soil Structures[C]∥Proceedings of the 8th International Conference on Geosynthetics, Yokohama, Japan, September 18-22, 2006: 1113-1116.
[17]包承纲. 加筋土结构加筋机理的研究和设计方法的讨论[C]∥第4届全国土工合成材料加筋土学术研讨会论文集——加筋土结构的合理设计方法.武汉, 2013:1-41. (BAO Cheng-gang. Discussion on the Reinforcement Mechanism and Design Methods of Reinforced Soil Structure[C]∥Proceedings of the 4th China Symposium on Geosynthetic Reinforced Structure: Reasonable Design Method for Reinforced Soil Structure, Wuhan, 2013: 1-41. (in Chinese))
[18]朱海龙, 刑义川, 郭素琴, 等, 加筋土技术应用中的系统性分析[C]∥土工合成材料加筋——机遇与挑战. 北京:中国铁道出版社, 2009:30-40.(ZHU Hai-long, XING Yi-chuan, GUO Su-qin, et al. Experimental Investigation on Failure Types of Reinforced Sand Retaining Wall[C]∥Geosynthetic Reinforcement: Opportunities and Challenges, Beijing: China Railway Press, 2009: 30-40.(in Chinese))
[19]介玉新, 李广信.加筋土数值计算的等效附加应力法[J].岩土工程学报, 1999, 21(5):614-616. (JIE Yu-xin, LI Guang-xin. Equivalent Additional Stress Method of Numerical Analysis for Reinforced Soil Structure[J]. Journal of Geotechnical Engineering, 1999, 21(5): 614-616. (in Chinese))
