CAJ | 학술논문

依据等效黏弹性理论与蠕变理论，建立了描述一般应力状态饱和软土不排水循环应力应变响应的拟动力本构关系。该关系包括三个基本参数：循环剪切模量，阻尼比与增量循环累积应变。利用循环剪切模量与阻尼比随土单元八面体剪应变的变化描述循环荷载作用下软土的不排水循环应变，依据 Mises 蠕变势函数与正交流动法则确定循环累积应变增量。通过饱和软土不固结不排水循环三轴压缩试验确定这些变化关系。按确定出的参数预测循环三轴拉伸与循环扭剪试验结果。预测出的循环拉伸试验剪切模量和阻尼比随八面体剪应变的变化与试验结果吻合。对于循环扭剪试验，当循环偏应力与静偏应力方向一致时，预测出的循环累积应变随循环次数的变化与试验结果基本一致；当循环偏应力与静偏应力作用方向不一致时，预测出的循环累积应变与试验结果相比偏小。
의거등효점탄성이론여연변이론，건립료묘술일반응력상태포화연토불배수순배응력응변향응적의동력본구관계。해관계포괄삼개기본삼수：순배전절모량，조니비여증량순배루적응변。이용순배전절모량여조니비수토단원팔면체전응변적변화묘술순배하재작용하연토적불배수순배응변，의거 Mises 연변세함수여정교류동법칙학정순배루적응변증량。통과포화연토불고결불배수순배삼축압축시험학정저사변화관계。안학정출적삼수예측순배삼축랍신여순배뉴전시험결과。예측출적순배랍신시험전절모량화조니비수팔면체전응변적변화여시험결과문합。대우순배뉴전시험，당순배편응력여정편응력방향일치시，예측출적순배루적응변수순배차수적변화여시험결과기본일치；당순배편응력여정편응력작용방향불일치시，예측출적순배루적응변여시험결과상비편소。
In this study,we develop a pseudo-dynamic relationship describing undrained cyclic stress-strain responses of soft clay elements under general stress conditions,based on equivalent visco-elastic and creep theories.This relationship includes three basic parameters:the cyclic shear modulus,the damp ratio and the cyclic accumulative strain increment.The variation of the cyclic shear modulus and the damp ratio with the octahedral shear strain are used to describe undrained cyclic strain.The cyclic accumulative strain increment is determined based on the Mises creep po-tential and the associated flow rule.We determine these by unconsolidated and undrained cyclic triaxial compression tests of soft soils.We made cyclic triaxial extension and torsion test predic-tions using the parameters determined.Predicted variations of the cyclic shear modulus and the damping ratio with the octahedral shear strain are basically in agreement with the test results from the cyclic triaxial extension tests.Predicted variations of the cyclic accumulative strain with respect to the number of cycles is also basically in agreement with the test results for the cyclic torsion tests wherein the static and cyclic deviatoric stresses have the same direction.The predic-ted variations of the cyclic accumulative strain are less than those of the test results when the di-rection of the static deviatoric stress is different from the direction of the cyclic deviatoric stress in the cyclic torsion tests.