【作者】 周子龙；

【导师】 李夕兵；

【作者基本信息】 中南大学 ， 岩土工程， 2007， 博士

【摘要】 针对深部岩石力学实验与理论研究严重不足这一现状，从深部岩石动静组合受载这一应力状态入手，研制了基于霍布金逊压杆(SHPB)原理的动静组合加载试验系统，可实现中高应变率下岩石的静载0-200MPa、动载0-500MPa的动静组合加载；运用小波变换，实现了实验信号的滤波消噪；基于VC++，开发了相应的数据处理软件。分析了存在于脆性材料大杆径SHPB实验系统及本文实验系统中的界面摩擦、波形弥散、惯性效应、截面匹配、试样应力均匀及恒应变率加载问题；用矩形波、三角形波、半正弦波进行对比分析，揭示了减小波形弥散和实现试样应力均匀的理想波形；在进行大量异形冲头方法和整形器方法实验的基础上，得出了试样恒应变率加载的实现条件；为获得特定加载应力波，提出了基于三维有限元和神经网络的冲头反向设计理论与设计流程。基于随机有限元方法，探讨了影响SHPB实验结果离散性的各项计算参数；在开展大量动静组合加载实验的基础上，揭示了组合加载对岩石特性的影响；基于实验数据，建立了动静组合加载下岩石的力学本构模型；在分析动静组合加载下岩石破坏模式的基础上，研究了岩石破碎的分形特性，并结合重整化群方法进行了岩石破碎分维的合理预测。对照国内外研究成果，本文主要取得如下创新性成果：a)研制了中高应变率段岩石动静组合加载实验系统，为深部岩石力学研究提供了实验平台；b)分析了减小波形弥散和实现应力均匀的有效途径，揭示了实现试样恒应变率变形的加载条件；c)提出了基于三维有限元和神经网络的冲头反向设计理论与设计流程，完善了异形冲头实验的理论与方法体系；d)建立了动静组合加载下岩石的力学本构模型，丰富了深部岩石力学理论；e)揭示了动静组合加载下岩石的破坏机理和分形破碎规律，实现了破碎分维值的重整化群方法预测。更多还原

【Abstract】 Due to the shortage of experimental and theoretical research on rock mechanics in deep engineerings, an innovative testing system based on SHPB(Split Hopkinson Pressure Bar) was constructed considering the stress state of rock with static-dynamic coupling loads. It can be used to carry out tests on rock under medium and high strain rate with 0-200MPa static loads and 0-500MPa dynamic loads. The data processing software was developed based on Visual C＋＋language, where the collected signals were denoised with wavelet method.The friction effect, wave dispersion, inertia effect, section accordance, stress equilibrium and constant strain rate of specimen in constructed system and other large diameter SHPB system for brittle materials were analyzed, and the performances of rectangular, tiangle, and half-sine wave were presented to show ways to get perfect loading wave. Based on experiments with novel striker method and wave-shaper method, the expression of required incident wave was deducted. In order to produce arbitrary possible incident wave, an back-design theory was brought forward.Based on Stochastic Finite Element Method, the parameters of SHPB test leading to the scattering of calculated results were discussed. With lots of test results, the mechanical characters of rock were concluded, and the constitutive model was fabricated. After statistics of broken pieces of specimen, the fractal characteristics of rock fragmentation was investigated and the fractal dimension value was reasonablely predicted with renormalization method.Referring to the corresponding researches at home and abroad, there are several points of highlight as follows:a) An innovative testing system was constructed for tests of rock with static-dynamic coupling loads under medium and high strain rate, which supply a platform for research of deep-level rock mechanics.b) The effective way to reduce wave dispersion and realize stress equilibrium of specimen was discussed and the expression of required incident wave for constant strain rate tests was put forward.c) A new way to back-design strker for arbitrary stress wave was established, which leads to the perfection of the theory system of novel striker testing technique.d) The constitutive model of rock under static-dynamic coupling loads was presented, which enriches the rock mechanics for deep engineerings. e) The failure mechanism and the fractal characteristics of rock fragmentation under coupling loads were concluded and the fractal dimension value was reasonablely predicted with renormalization method.更多还原