摘要
针对华南"红层"软岩遇水软化的复杂系统演化问题,从其软化过程中是否形成耗散结构的思路出发,研究了软岩系统非线性软化特征.结果表明:软岩与水相互作用系统是一个开放的复杂系统,在内部非线性作用下逐渐演化至非平衡状态,其软化过程中可以形成有序的耗散结构.在此基础上,采用耗散结构理论系统分析了软岩软化过程中耗散结构的形成机制:软岩软化的过程经历了近平衡态、远离平衡自组织态与远离平衡临界态3个阶段,并最终通过非平衡相变形成了具有一定稳定性的耗散结构.最后基于软岩软化过程中结构分维值演化规律,初步建立了软岩耗散结构形成的分岔演化模型,并将模型应用于软岩饱水软化试验的临界分岔现象分析中.分析表明软岩耗散结构是在系统经历多次倍周期分岔,通过不断地从稳定到失稳再到稳定的过程后形成的.其中3个月与6个月这两个时间点具有显著的临界特征,这是深入研究软岩软化耗散动力学过程的切入点.
Aiming at the complex issue of system evolution in softening process of saturated red-bed soft rocks, the research on softening characteristics of soft rocks is carried out from the aspects of systemic openness, far-from equilibrium behavior and internal nonlinear mechanism to affirm the occurrence of dissipative structure in softening process. On this basis, dissipative structure theory is adopted to systematically analyze the formation mechanism of dissipative structure in softening process of saturated soft rocks. The result shows that softening process contains three stages: Near-equilibrium state, far-from-equilibri- um self-organizing state and far-from-equilibrium critical state, and ultimately, the way of non-equilibrium phase transition leads to the generation of soft rock dissipative structure. Finally, based on the evolution law of structure fraetal dimension, a bifurcation evolution model is preliminarily established to describe the formation process of soft rock dissipative structure. The result of applying this model to analyze the critical bifurcation phenomena occurring in softening tests of saturated soft rocks indicates that this soft rock dissipative structure is formed after experiencing the process of period-doubling bifurcation and destabilization for many times, and the times of three months and six months present obvious critical characteristics which are two breakthrough points for further study on dissipative dynamic softening process of soft rocks in future.
出处
《地球科学(中国地质大学学报)》
EI
CAS
CSCD
北大核心
2009年第3期525-532,共8页
Earth Science-Journal of China University of Geosciences
基金
中国高技术研究发展计划(No.2007AA11Z112)
国家自然科学基金项目(Nos.59809008
40672194)
高等学校博士学科点基金项目(No.20060558060)
广东省自然科学基金重点项目(Nos.013188
06104932)
关键词
软岩
软化
耗散结构
非平衡相变
临界分岔
机制
soft rocks
softening
dissipative structure
non-equilibrium phase transition
critical bifurcation
mechanism.