A Study on Microscopic Deformation Behavior of Rocks under Compression

岩石受压微观变形行为研究

基本信息

批准号：
07455405
负责人：
ISHIJIMA Yoji
金额：
$ 5.06万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

Uniaxial compression tests and triaxial compression tests under confining pressure of 5 MPa were carried out on cylindrical specimens of lnada granite, whose axis coincided with rift or grain plane. Load was removed when circumferential strain reached certain values. P-wave velocity of loaded specimens in axial and radial directions was measured. Replicas of sections, whose normal coincided with loading axis, were observed undera microscope.P-wave velocity in the axial direction for specimens were larger than that for unloaded specimens in uniaxial case. On the other hand, that decresed slightly with triaxial loading. P-wave velocity in the radial directions decreased in the both uniaxial and triaxial cases. That in R-and G-direction was small than that in H-direction. P-wave velocity in the uniaxial case was smaller than that in the triaxial case with reference to circumferential strain value at unloading. They showed similar behaviors with reference to permanent circumferential strain value.The thin section method with a blue resin and the replica method were used in order to observe cracks. Determination of mineral type with the replica method was difficult. However, preparation of replica is easy and the method enables observation of cracks in opaque minerals.Crack density was evaluated with the scan-line method. The crack density increased with circumferential strain magnitude at unloading. That in triaxial casa was smaller than that in uniaxial case with reference to circumferential strain value at unloading. On the other hand, they showed similar behaviors with reference to permanent circumferential strain. In the uniaxial case, cracks that oriented to rift or grain plane dominated. Crack directivity was not observed in the triaxial case. P-wave velocity decreased with crack density. Rate of the decrease in the triaxial case was larger than that in the uniaxial case. Effects of measuring direction (wave path and scan line) was not observed.

在5 MPa的限制压力下进行单轴压缩测试和三轴压缩测试，在LNADA花岗岩的圆柱样品上进行了，其轴与裂谷或谷物平面一致。当周向应变达到某些值时，将负载去除。测量了在轴向和径向方向上负载标本的P波速度。在显微镜下观察到的截面的副本与载荷轴的正常相吻合。在单轴情况下，在轴向方向上的P-Wave速度大于卸载标本的速度。另一方面，由于三轴载荷略微腐烂。在径向方向上的P波速度在单轴和三轴病例中都降低。在r和g方向上，这比h方向小。单轴病例中的P波速度小于三轴情况下的P波速度，指参照卸载时的圆周应变值。他们参考了永久性圆周应变值表现出相似的行为。使用蓝色树脂和复制方法的薄截面方法用于观察裂缝。用复制方法确定矿物质类型很困难。但是，复制品的制备很容易，该方法可以观察不透明矿物质中的裂纹。用扫描线方法评估了裂缝密度。裂缝密度随卸载时的圆周应变幅度增加。在三轴CASA中，在卸载时圆周应变值的单轴情况下的casa小。另一方面，他们参考永久性圆周菌株显示出相似的行为。在单轴情况下，裂纹是指向裂谷或谷物平面占主导地位的裂纹。在三轴情况下未观察到裂纹方向。 P波速度随裂纹密度降低。三轴情况下的降低率大于单轴病例的降低。未观察到测量方向（波路和扫描线）的影响。