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| Mechanism of three dimensional elastic-plastic expansion of cylindrical cavity in saturated clay |
| LI Jingpei1，2，TANG Jianhua1，2，LI Lin1，2，ZHONG Guangyu3 |
| (1. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；2. Department of Geotechnical Engineering，Tongji University， Shanghai 200092，China；3. Shanghai Nanhui Construction Group Co.，Ltd.，Shanghai 201399，China) |
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Abstract The current solutions of cylindrical cavity expansion are based on an elastic-perfect plastic assumption. The consistency in shear deformation and shear failure is not warranted and the over-consolidation ratio and three-dimensional strength characteristic of soil also are not incorporated into the solutions. Therefore，a large deviation between the theoretical solutions and the actual conditions exists. To obtain the exact solution of elasto-plastic expansion of cylindrical cavity，the SMP criterion revised by Cam-Clay model was adopted using the associated flow rule in the stress transformed space，which can incorporate the over consolidation ratio and the soil strength in three-dimensional stresses state. The problem was reduced to a system of first order ordinary differential equations in the plastic region using the large strain deformation theory. The accurate solution to cylindrical cavity expansion was obtained by means of a numerical method under the elastic-plastic boundary conditions. Finally，the stress around the cavity during the cavity expansion process was discussed by comparing with the solutions based on the MCC model. The results showed that the solutions with SMP-MCC model reflected the change of stress field more actually，because the three-dimensional strength of soil was considered in the present solution.
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| [1] GIBSON R E，ANDERSON W F. In-situ measurement of soil properties with the pressuremeter[J]. Civil Engineering and Public Works Review，1961，56(658)：615–618.
[2] PALMER A C. Undrained plane-strain expansion of a cylindrical cavity in clay：a simple interpretation of the pressuremeter test[J]. Geotechnique，1972，22(3)：451–457.
[3] CHANG M F，TEH C I，CAO L F. Undrained cavity expansion in modified Cam clay II：Application to the interpretation of the piezocone test[J]. Geotechnique，2001，51(4)：335–350.
[4] RANDOLPH M F，CARTER J P，WROTH C P. Driven piles in clay-the effects of installation and subsequent consolidation[J]. Geotechnique，1979，29(4)：361–393.
[5] 李月健，陈云敏. 黏性土中打桩引起的应力场及其对土体强度的影响[J]. 铁道学报，2001，23(4)：88–93.(LI Yuejian，CHEN Yunmin. Stress filed and its effect on soil strength caused by pile installation in clay ground[J]. Journal of the China Railway Society，2001，23(4)：88–93.(in Chinese))
[6] 饶平平，李镜培，刘 颖. 邻近斜坡沉桩挤土球孔扩张分析[J]. 岩土工程学报，2011，33(增2)：321–325.(RAO Pingping，LI Jingpei，LIU Ying. Spherical cavity expansion-induced soil squeezing effect adjacent to slope[J]. Chinese Journal of Geotechnical Engineering，2011，33(Supp.2)：321–325.(in Chinese))
[7] VESIC A S. Expansion of cavities in infinite soil mass[J]. Journal of the Soil Mechanics and Foundations Division，1972，98(SM3)：265–269.
[8] CARTER J P，BOOKER J R，YEUNG S K. Cavity expansion in cohesive frictional soils[J]. Geotechnique，1986，36(3)：349–358.
[9] COLLINS I F，YU H S. Undrained cavity expansions in critical state soils[J]. International Journal for Numerical and Analytical Methods in Geomechanics，1996，20(7)：489–516.
[10] CAO L F，TEH C I，CHANG M F. Undrained cavity expansion in modified Cam clay I：Theoretical analysis[J]. Geotechnique，2001，51(4)：323–334.
[11] SUN D A，MATSUOKA H，YAO Y P. An anisotropic hardening elastoplastic model for clays and sands and its application to FE analysis[J]. Computers and Geotechnics，2004，31(1)：37–46.
[12] YAO Y P，SUN D A. Application of Lade?s criterion to Cam-clay model[J]. Journal of Engineering Mechanics，2000，126(1)：112–119.
[13] MATSUOKA H，SUN D A. The SMP concept-based 3D constitutive models for geomaterials[M]. [S.l.]：CRC Press，2006：25–27.
[14] 姚仰平，侯 伟. 土的基本力学特性极其弹塑性描述[J]. 岩土力学，2009，30(10)：2 881–2 902.(YAO Yangping，HOU Wei. Basic mechanical behavior of soils and their elastoplastic modeling[J]. Rock and Soil Mechanics，2009，30(10)：2 881–2 902.(in Chinese))
[15] MATSUOKA H，YAO Y P，SUN D A.The Cam-clay models revised by the SMP criterion[J]. Soils and Foundations，1999，39(1)：81–95.
[16] WOOD D M. Soil behaviour and critical state soil mechanics[M]. Cambridge：Cambridge University Press，1990：486.
[17] 连镇营，韩国城，姚仰平. 基于SMP准则的改进剑桥模型及其在基坑工程中应用[J]. 大连理工大学学报，2002，42(1)：93–97.(LIAN Zhenying，HAN Guocheng，YAO Yangping. Revised Cam-clay model based on SMP criterion and its application to foundation engineering[J]. Journal of Dalian University of Technology，2002，42(1)：93–97.(in Chinese))
[18] 姚仰平，路德春，周安楠，等. 广义非线性强度理论及其变换应力空间[J]. 中国科学：E辑，2004，34(11)：1 283–1 299.(YAO Yangping，LU Dechun，ZHOU Annan，et al. Generalized non-linear strength theory and transformed stress space[J]. Science in China：Series E，2004，34(11)：1 283–1 299.(in Chinese))
[19] CHEN S L，ABOUSLEIMAN Y N. Exact undrained elasto-plastic solution for cylindrical cavity expansion in modified Cam Clay soil[J]. Geotechnique，2012，62(5)：447–456. |
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2016, Vol. 35 
