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通过对岩石加载–蠕变–卸载的能量转换与变形机制分析,利用RLW–2000型岩石三轴流变仪,对2组岩石进行单轴分级加载蠕变试验,分析岩石不同应变差值下能量的耗散过程,确定岩石不同加载水平(或循环次数)与变形模量的关系,研究加载蠕变与应力卸载的曲线路径。结果表明:岩石分级加载蠕变的能量转换可分为加载应变与蠕变应变2个部分,随着每一级载荷作用下应变差的增加,岩石塑性应变能与耗散能呈非线性增加趋势,且塑性应变能曲线与耗散能曲线的开口、应变差及岩石损耗能量也越大;在相同加载水平下,岩石塑性应变能大于耗散能,且应变差与塑性应变能、耗散能的关系可分别用二次多项式、乘幂函数进行描述;岩石变形模量随着加载水平(或循环次数)的增加而变大,表现为先突然增加较大到缓慢增加至趋于相对平缓,相同加载水平(或循环次数)下,高强度岩石变形模量大于低强度岩石变形模量;岩石加载蠕变应变与卸载应力松弛均随加载水平的提高而增大,相同加载水平下,高强度岩石蠕变应变小于低强度岩石蠕变应变,但高强度岩石应力松弛大于低强度岩石应力松弛,高强度岩石加载曲线穿越上一级载荷卸载后的应力松弛区,而低强度岩石加载曲线则穿越上一级加载水平后的蠕变应变区。
Through the energy conversion and deformation mechanism analysis of rock loading-creeping-unloading, the two groups of rocks were subjected to uniaxial graded-loading creep test with RLW-2000 rock triaxial rheometer to analyze the energy of rock under different strain differences The relationship between the different loading levels (or the number of cycles) and deformation modulus of the rock is determined, and the curve path of loading creep and stress unloading is studied. The results show that the energy conversion of rock loading creep can be divided into two parts: loading strain and creep strain. With the increase of strain difference under each load, the plastic strain energy and dissipation energy of rock increase nonlinearly , And the plastic strain energy curve and the dissipation energy curve of the opening, the strain difference and the rock loss energy is greater; the same loading level, the rock plastic strain energy is greater than the dissipation energy, and the strain difference and plastic strain energy, dissipation energy Can be described by quadratic polynomials and power exponentiation, respectively. The deformation modulus of rocks increases with the increase of loading level (or cycle number), and then increases suddenly and then increases slowly until tends to be relatively flat, Under the same load level (or cycle number), the deformation modulus of high-strength rock is larger than that of low-strength rock. The creep strain and unloading stress relaxation of rock increase with the increase of loading level. Under the same load level, The creep strain of rock is less than the creep strain of low-strength rock, but the stress relaxation of high-strength rock is greater than the stress relaxation of low-strength rock. The high-strength rock loading curve passes through the upper-level load after unloading Relaxation zone, rock strength and low creep strain across the load curve of the upper region of a rear loading levels.