【摘要】 介质电阻率变化的方向性与主应力方向的关系研究一直受到岩石电阻率实验和地震学等学科的关注.本文在电极面4cm×8cm,6cm×12cm,8cm×16cm和4.6cm×10cm的10块分别为花岗岩、凝灰质粗砂岩(夹砾石)和细晶花岗岩标本上及100cm×100cm的1块人工合成模型上,采用对称四极法布设多位置、多极距、多方位电阻率测线,用单轴压缩、二维约束差应力压缩、低围压三轴差应力压缩和真三轴差应力压缩方式加载.其中在单轴压缩和低围压三轴压缩加载方式下,7块岩石标本中的4块被压破,3块没有被压破,只压到电阻率出现明显的下降异常时卸压.另在上述10块岩石标本中,还有3块是电阻率原始各向异性标本.将这样11块标本所获得的多位置、多极距、多方位测线电阻率资料,按从开始加载到破裂的过程,分成30%附近破裂应力段、50%附近破裂应力段、80%附近破裂应力段和100%破裂应力段,研究同一测点多方位测道中该4个破裂应力段视电阻率变化最大(最小)幅度测线方位与力源最大主压应力方位的关系,结果未发现二者之间有确定的关系.更多还原

【Abstract】 Study on the relation between directional characteristics of resistivity changes and principal stress plays an important role in rock resistivity experiments and seismology. Using symmetrical four-electrode method, multi-position, multi-space and multi-direction resistivity arrays were arranged on 10 samples of granite, tuffaceous gritrock (with inclusion of gravel) and aplite granite, which have surface sizes of 4 cm×8 cm, 6 cm×12 cm, 8 cm×16 cm, 4.6 cm×10 cm, respectively, and 1 synthetic model of 100 cm×100 cm. The experiments were carried out with uniaxial, planar elastic constraint, low confining pressure and true triaxial compressions. In the uniaxial and low confining pressure tests, 4 of the 7 rock samples were loaded to rupture with macro-fractures, the other 3 were only loaded to the abnormal stage when resistivity began to decrease obviously. 3 of the 10 rock samples are samples of original resistivity anisotropy. According to the loading process from beginning to end, the resistivity data obtained from all of the 11 samples in the multi-position, multi-space and multi-direction resistivity arrays were divided into 4 rupture stress sections, namely, about 30%, about 50% and about 80% rupture stress sections and 100% rupture stress section. Thereby, the relation between directional characteristics of resistivity changes and principal stress corresponding to the 4 rupture stress sections is studied. However, the results show no confirmative relation between the two.更多还原