RESEARCH ON FAILURE MECHANISM OF ANTI-SLIDING MICROPILES BASED ON ELASTOPLASTIC MODEL
XIN Jianping1，2，ZHENG Yingren1，2，TANG Xiaosong1，2
(1. Department of Civil Engineering，Logistical Engineering University，Chongqing 401311，China；2. Chongqing Key Laboratory of Geomechanics and Geoenvironment Protection，Logistical Engineering University，Chongqing 401311，China)
Abstract：The failure mechanism of micropiles in rock-soil slope，rock slope and soil slope was obtained based on strengthen reduction and the finite difference program FLAC. Solid elements and Mohr-Coulomb ideal elastoplastic model were used for piles on the purpose of getting the failure state. The microplies getting into plastic state based on its mechanical characteristics，then the failure mechanism of micropiles from failure state，deformation and internal force were analyzed. Safety factor and failure mode of slopes reinforced by microplies are obtained. Then a model test of soil slope reinforced by micropiles is compared with its 1∶1 numerical simulation and the results conform to each other. It shows that the numerical simulation method is correct and can be utilized for slope prototype calculation. Results indicate that the failure mechanisms of micropiles in different types of slopes are completely different. For mixed rock and soil slope，bending shear failure in sliding zone and bending failure above sliding zone happens to piles. For rock slope，the failure of piles is mainly shear failure in sliding zone. For soil slope，bending failure of piles happens on both sides of sliding zone.
ZHANG L，SILVA F，GRISMALA R. Ultimate lateral resistance to piles in cohesionless soils[J]. Journal of Geotechnical and Geoenvironmental Engineering，2005，131(1)：78-83.
[2]
张丹丹，刘小丽，黄 敏，等. 微型群桩加固岩石滑坡受力特性的有限元分析[J]. 工程地质学报，2011，19(增1)：502-507.(ZHANG Dandan，LIU Xiaoli，HUANG Min，et al. Finite element analysis on mechanical characteristics of micropile group for rock slide reinforcement[J]. Journal of Engineering Geology，2011，19(Supp.l)：502-507.(in Chinese))
[3]
ZHENG Y R，DEN C J，TANG X S，et al. Development of finite element limiting analysis method and its application in geotechnical engineering[J]. Engineering Sciences，2007，3(5)：10-36.
[4]
ZHENG Y R，TANG X S，ZHAO S Y，et al. Strength reduction and step-loading finite element approaches in geotechnical engineering[J]. Journal of Rock Mechanics and Geotechnical Engineering，2009，1(1)：21-30.
[5]
Itasca Consulting Group，Inc..Fast Lagrangian analysis of continua in three dimensions(version 3.0)，users¢manual[R]. [S. l.]：Itasca Consulting Group，Inc.，2003：56-79.
[6]
赵尚毅，郑颖人，张玉芳. 极限分析有限元法讲座——II有限元强度折减法中边坡失稳的判据探讨[J]. 岩土力学，2005，26(2)：332-336.(ZHAO Shangyi，ZHENG Yingren，ZHANG Yufang. Study on slope failure criterion in strength reduction finite element method[J]. Rock and Soil Mechanics，2005，26(2)：332-336.(in Chinese))
[7]
孙书伟，朱本珍，马惠民，等. 微型桩群与普通抗滑桩抗滑特性的对比试验研究[J]. 岩土工程学报，2009，31(10)：1564-1570.(SUN Shuwei，ZHU Benzhen，MA Huimin，et al. Model tests on anti-sliding mechanism of micropile groups andanti-sliding piles[J]. Chinese Journal of Geotechnical Engineering，2009，31(10)：1564-1570.(in Chinese))
[8]
胡毅夫，王庭勇，马 莉. 微型抗滑桩双排单桩与组合桩抗滑特性研究[J]. 岩石力学与工程学报，2012，31(7)：1 499-1 505.(HU Yifu，WANG Tingyong，MA Li. Research on anti-slidingcharacteristics of single double-row and composite anti-slide micropiles[J].Chinese Journal of Rock Mechanics and Engineering，2012，31(7)：1 499- 1 505.(in Chinese))
[9]
BROWN D A，SHIE C F. Numerical experiments into group effects on the response of piles to lateral loading[J]. Computers and Geotechnics，1990，10(3)：211-230.
[10]
SADEK M，SHAHROUR I，MROUEH H. Influence of micro-pile inclination on the performance of a micro-pile network[J]. Ground Improvement，2006，10(4)：165-172.
[11]
陈正，梅岭，梅国雄. 柔性微型桩水平承载力数值模拟[J]. 岩土力学，2011，32(7)：2219-2224.(CHENZheng，MEI Ling，MEI Guoxiong. Numerical simulation of lateral bearing capacity of flexible micropile[J]. Rock and Soil Mechanics，2011，32(7)：2219-2224.(in Chinese))
[12]
冯君，周德培，江南，等. 微型桩体系加固顺层岩质边坡的内力计算模式[J]. 岩石力学与工程学报，2006，25(2)：284-288.(FENG Jun，ZHOU Depei，JIANG Nan，et al.A model forcalculation of internal force of micropile system to reinforce bedding rock slop[J].Chinese Journal of Rock Mechanics and Engineering，2006，25(2)：284-288.(in Chinese))
[13]
朱宝龙，陈 强，巫锡勇，等. 注浆微型桩群支护体系作用机制及其工程应用[M]. 北京：科学出版社，2009：23-50.(ZHUBaolong，CHENQiang，WUXiyong，et al. Action mechanismand engineering application of grouting micropiles group in supporting system[M]. Beijing：Science Press，2009：23-50.(in Chinese))
[14]
杨 静. 微型桩加固边坡的动力响应特征及抗震计算方法研究[硕士学位论文][D]. 成都：西南交通大学，2012.(YANGJing. Study on dynamic response characteristics of reinforced slope with micropiles and the seismicanalysis method[M. S. Thesis][D]. Chengdu：Southwest Jiaotong University，2012.(in Chinese))
2014, Vol. 33 
