冲击载荷下岩石的损伤特性分析

AN ANALYSIS OF SHOCK-INDUCED DAMAGE IN ROCKS

把岩石类脆性材料受冲击波加载造成的损伤与弹性纵波速度的变化联系起来，定义了损伤度Ｄ，并且以辉长岩（Ｇａｂｂｒｏ）和石灰岩（Ｌｉｒｎｅｓｔｏｎｅ）为例，测量了冲击波加载后靶体的损伤度分布。同时对冲击加载后含损伤的辉长岩，测量了一维准静压下弹性纵波速度的变化和抗压强度，分析了含损伤材料的静力学行为。

A definition of shock damage parameter,D=1-(c_p/c_(po))￣2,is propased for rock-like brittle materials,where c_(po) and c_p are elastic longitudinal wave velocities of unshocked andshocked materials,respoctively. Fullowing this definition,damage distribbutions in shocked Gabroand Limestone were experimentally miasured,,in which c_p values were measured by an ultrasonictransmission technique,For shock damaged gabbro, the characteristics of elastic longitudinal wavevelocity and com pressive strength under quasistatic uniaxial loading are also studied.In all thetested samples(with different initial damage parameter) a large increment of elastic velocities areobserved under the stresses ranging from 0 to 50 MPa. We suspect this behaviour is due to a mi-crocracks(induced by the shock loading ) re-closing process.After microcracks re-closing,theshocked gabbror with initial damage D_0<0.1 have nearly the same elastic wave velocities andcompressive strengthes as the unshocked ones.For the samples with initial damage D_0>0.1 ,how-ever.their values are much reduced and could not be rebounded to the intrinsic values.