CAJ | 학술논문

柱孔扩张理论广泛用于旁压试验机制分析、沉桩挤土效应等岩土工程问题中。基于经典的Vesic孔扩张理论，采用能够考虑中主应力效应的广义SMP屈服准则，并结合有限应变理论对均质土体中柱孔扩张问题进行分析，根据应力路径假设提出确定塑性区平均体应变的解析步骤。通过大量变参数计算给出具有不同刚度指标Ir、泊松比n和内摩擦角j的土中柱孔扩张极限状态下的塑性区平均体应变、孔扩张半径比和孔扩张系数。分析结果表明， Ir、n、j越大，塑性区平均体应变越小，塑性区半径比越大，孔扩张系数越大；随着Ir增加，j的变化对孔扩张系数的影响更显著。同时，将结果与基于Mohr-Coulomb 准则的孔扩张解答进行比较，探讨不同土性参数时中主应力效应对孔扩张系数的影响。文中分析方法及给出的考虑中主应力效应的柱孔扩张系数表可为原位试验分析及桩侧摩阻力估算提供参考。
주공확장이론엄범용우방압시험궤제분석、침장제토효응등암토공정문제중。기우경전적Vesic공확장이론，채용능구고필중주응력효응적엄의SMP굴복준칙，병결합유한응변이론대균질토체중주공확장문제진행분석，근거응력로경가설제출학정소성구평균체응변적해석보취。통과대량변삼수계산급출구유불동강도지표Ir、박송비n화내마찰각j적토중주공확장겁한상태하적소성구평균체응변、공확장반경비화공확장계수。분석결과표명， Ir、n、j월대，소성구평균체응변월소，소성구반경비월대，공확장계수월대；수착Ir증가，j적변화대공확장계수적영향경현저。동시，장결과여기우Mohr-Coulomb 준칙적공확장해답진행비교，탐토불동토성삼수시중주응력효응대공확장계수적영향。문중분석방법급급출적고필중주응력효응적주공확장계수표가위원위시험분석급장측마조력고산제공삼고。
The theory of cylindrical cavity expansion has been widely used in many geotechnical engineering, such as analysis of pressure meter testing and effect of pile driving. Extended spatial mobilization plane (SMP) theory, which can display the effects of intermediate principal stress, in combination of finite strain theory, is used to analyze cylindrical cavity expansion problem in homogeneous soil. An analytical procedure to determine average volumetric strain of plastic zone is developed according to stress path hypothesis. Accordingly, “nondimensional” plastic zone radius and factors of cylindrical cavity expansion are estimated for varied rigidity index rI , Poisson ratio v and frictional angle j. It is concluded that average volumetric strain decreases and“nondimensional”plastic zone radius and factors of cylindrical cavity expansion increase with the increase of rI 、n、j. Variation of j has significant effects on factors of cylindrical cavity expansion in the case of greater rI . Furthermore, a comparative study of the solutions based on extended SMP and those based on Mohr-Coulomb is made to examine the effects of intermediate principal stress on cylindrical cavity expansion for various soils. The values of factors of cylindrical cavity expansion considering the effects of intermediate principal stress presented in this paper are of great significance for analyzing in-situ tests and estimating ultimate lateral friction of piles.