摘要
明确可液化土体的振动孔压增长过程是土体液化分析和液化效应评价的关键问题。基于Moore型触变性流体结构理论,利用不同类型土体的32个不排水循环三轴试验证实了液化过程中的土体内部结构的破坏过程与振动孔压增长过程存在等价关系,验证了循环荷载下可液化土体的孔压触变机制。在此基础上,基于孔压触变流体速率方程构建了可液化土体的振动孔压增长模型,发现模型蕴含的振动孔压产生和增长机制可从能量角度获得合理解释。试验结果表明,模型中的振动孔压增长速率参数与土体有效围压、初始相对密度及循环应力比密切相关。利用该模型对不排水循环三轴试验进行了仿真模拟,验证了模型的合理性和可靠性。最后,讨论了模型的主要特点及可能的应用前景,为土体液化分析提供一种新的技术手段。
It is a key problem to confirm the growth process of dynamic pore pressure of the liquefiable soils in the analysis of liquefaction potential of soils or evaluation of liquefaction effect. Based on the structural theory of the Moore thixotropic fluid, 32 groups of undrained cyclic triaxial experiments on different types of soils are performed to verify the corresponding relationship between internal structure parameters of soils and dynamic pore pressure in the whole liquefaction process. The thixotropic mechanism induced by the pore water pressure in the liquefiable soils under cyclic loading is confirmed. Moreover, a dynamic pore pressure growth model for the liquefiable soils is proposed based on the rate equation for the thixotropic fluid induced by pore pressure. It is found that the generation and growth mechanism of dynamic pore pressure implied in the proposed model can be explained reasonably from the viewpoint of energy. The experimental results show that the parameter of growth rate of dynamic pore pressure in the model is closely related to the effective confining pressure, initial relative density and cyclic stress ratio. The proposed model is used to simulate the undrained cyclic triaxial experiments, and accordingly the rationality and reliability of the model are proved. Finally, the main characteristics and potential applications of the proposed model are discussed. This study provides a new technical means for the liquefaction analysis of soils.
作者
王志华
何健
高洪梅
王炳辉
沈吉荣
WANG Zhi-hua;HE Jian;GAO Hong-mei;WANG Bing-hui;SHEN Ji-rong(Research Center of Urban Underground Space, Nanjing Tech University, Nanjing 210009, China;School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2018年第12期2332-2340,共9页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51678300,51378257,51309121)
江苏省普通高校研究生科研创新计划项目(KYLX16_0603)
关键词
可液化土体
触变性流体
速率方程
振动孔压
不排水循环三轴试验
liquefiable soil
thixotropic fluid
rate equation
dynamic pore pressure
undrained cyclic triaxial experiment
