岩石变形破坏过程中试件尺度对断裂参数的影响  

Effect of Size of Rock Sample on Fracture Parameters

作　　者：张流[1] 李彪[1] 高平[1] 

机构地区：[1]国家地震局地质研究所

出　　处：《中国地震》1993年第2期121-128,共8页Earthquake Research in China

基　　金：国家自然科学基金;地震科学联合基金

摘　　要：采用三轴压缩实验方法,以不同尺寸的大理岩作样品,测定并研究了试件尺度对岩石剪切断裂参数的影响。样品的D(直径)×L(长度)从20mm×44mm到90mm×198mm。围压从20MPa至50MPa,以30MPa为主。结果表明:断裂能G、特征位移δ~*及其平均值δ、弱化带宽ω均随样品尺度的增加而增加,一般关系式为 G=G_0+K_gD~π δ=δ_0+k_δD^M ω=ω_0+K_ωD^P式中D为表征断裂尺度的量,其余均为常数。认为尺度因素可能是目前实验测定的断裂能与依据地震资料估算的断裂能之间有较大差异的主要原因。The effect of size of rock sample on fracture parameters was studied by means of triaxial testing. Marble was used as specimen with diameter times by length from 20mm × 44mm to 90mm × 198mm. Tests were performed at confining pressures from 20MPa to 50MPa, mainly 30MPa. It has been shown that fracture energy G, characteristic displacement δ* and its mean value δ, size of weakening zone ω increase with the increasing of sample size. A general expression can be .where D is a certain quantity describing the scale of sample. Go,δ0,ω0,κg,κδ,κω,n,m,p are constants. It is presented that the size effect is a main reason for the discrepancy of fracture energies between experimental measurement in laboratory and the estimation from seismological observation.

关 键 词：岩石 变形 三轴压缩 断裂参数 地震 

分 类 号：P315.2[天文地球—地震学]