岩石疲劳破坏的变形控制律、岩土力学试验的实时X射线CT扫描和边坡坝基抗滑稳定分析的新方法

介绍了近年来在岩土力学领域方面取得的一些进展:①关于岩石疲劳破坏试验方面的实验结果。大量的试验清楚表明岩石发生疲劳破坏时的变形量受岩石应力-应变全过程曲线控制的规律,介绍了这方面的试验技术及新型的岩石力学试验机--RMT机的特性,对岩石的I型和Ⅱ型分类作了评述。岩石疲劳试验结果也提示我们在研究岩石的强度理论时要特别重视从变形角度去探讨。②简要介绍了岩土力学室内试验方面的一项新的实验技术--实时X射线CT扫描的试验方法和原理。重点给出了南桥砂岩三轴试验的结果,并与典型的全过程曲线作了对比分析。这一新技术为岩土力学界提供了一种新手段,使宏观的力学性能与细观层次上的结构演变和裂纹萌生、扩展直到破坏有机地联系起来,为损伤研究提供了一种新的实验手段。③论述了采用强度储备概念求抗滑稳定安全系数方面的不足之处。基于力是矢量这一基本概念,提出了计算抗滑稳定安全系数的新方法--矢量和分析方法,并与传统分析方法作了对比,指出了这种新方法的优点。除了平面问题外,还论述了三维问题的计算方法和算式。

Deformation control law of rock fatigue failure,real-time X-ray CT scan of geotechnical testing,and new method of stability analysis of slopes and dam foundations

Some progresses were presented on the field of rock and soil mechanics for the past few years.Firstly,the test results of rock fatigue failure were discussed.A lot of tests have shown that the strain of fatigue failure is controlled by the whole stress-strain process curve.The testing techniques and the characteristics of the new testing machine for rock mechanics,RMT were introduced.The post-failure curves of type I and type II for rock were reviewed.More emphasis should be paid on the deformations in rock strength theory research based on the rock fatigue failure tests.Secondly,the creative testing technique in rock and soil mechanics experiments,the X-ray computerized tomography(CT) real-time scan was presented.The testing principles and methods were given.The triaxial testing results of Nanqiao sandstone were discussed.The whole stress-strain process curve of Nanqiao sandstone was obtained,and comparison between the former and the typical whole process curve was analyzed.A new approach was provided for rock and soil mechanics,and it connected the macro-mechanical properties of rock materials with the meso-structures including the compression and growth of microcracks,bifurcation,and crack fracture.Thirdly,the vector sum method of stability analysis for dam foundation and slope was given.The safety factor by the vector sum method was defined based on the vector characteristics of the forces.The significance of the vector sum method safety factor was clear in physics.The calculating process was simple,and it facilitated the application of this analysis method in engineering.The 2D slope calculation models with fixed circle slip surface,non-circle slip surface and curved slip surface were discussed.The results indicate that the safety factor obtained by vector sum method is in good agreement with the safety factors obtained by the limit equilibrium method.It is shown that the new method is more stable.The calculation formula of safety factor for the 3D problem by vectors sum method is also given.