适用于小型岩石试件的三轴压缩试验技术与设备的开发及其应用

为了用有限的岩石试样在室内进行大量的岩石力学试验测试，对直径10mm、长度20mm的小型岩石试件进行开发、制作。同时对S．Okubo等（2002）开发的透明围压容器进行改进，其围压可达10MPa左右。用此改进的试验设备对小型岩石试件进行三轴压缩试验。通过对田下凝灰岩的试验，由小型试件得到的力学参数——黏聚力和内摩擦角，与用常规试件获得的试验结果相一致。而且在载荷速率交替变换的试验中，用一个小型试件就可获得应力一应变曲线的载荷速率相关性。通过对三峡库区周边滑坡地带采集的岩石试样的测试，成功获得不同岩石的强度特性曲线及表示载荷速率相关性的参数。

DEVELOPMENT AND APPLICATION OF TRIAXIAL COMPRESSION TESTS WITH SMALL SPECIMENS

It is well known that rock properties often vary from site to site,and even from specimen to specimen.Soi,n many casesi,t requires many rock samples,much effort and cost to obtain the reliable data.In order to make more rock samples to carry out rock mechanical strength tests in the laboratory,a testing method with a small rock specimen(10 mm in diameter and 20 mm in length) was proposed and developed.In the triaxial compression test,the transparent triaxial vessel made of an acrylic acid resin,developed by Okubo et al.,was modified and used for the small specimen.The transparent vessel was designed for triaxial compression test under confining pressure up to 10 MPa.It was found that the mechanical parameters,cohesion and angle of internal friction,of Tage tuff with small specimens are very similar to the results obtained from regular specimen.Furthermore,the loading rate dependency of a stress-strain curve was also obtained by just one small specimen with the loading rate alternately switching during a test.The rock collected from landslide area near the Three Gorges Reservoir was also examined.By the proposed methodt,he strength characteristic curve and the loading rate dependency of the sample rock were accurately and economically obtained.