Characterization of Mechanical Behaviour of Saturated Sandstone Using a Newly Developed Triaxial Apparatus
Characterization of Mechanical Behaviour of Saturated Sandstone Using a Newly Developed Triaxial Apparatus
复制标题
DOI：
10.1007/s11340-012-9690-5
复制
发表时间：
2013-06
影响因子：
2.4
通讯作者：
P. Wasantha;W. Darlington;P. Ranjith
中科院分区：
文献类型：
--
作者：
P. Wasantha;W. Darlington;P. Ranjith
三轴测试是一种可靠且流行的测试方法，用于获取岩土设计和数值模拟中使用的岩石和土壤的关键特性。应配备足够的测试设备，准确模拟特定设计区域的地应力状态和水文地质条件。然而，文献中很少报道用于高精度测试岩石的多功能三轴仪器的规格和开发的详细信息。本文描述了为测试完整和节理岩石而开发的三轴设备的细节。新开发的设备能够获得有关测试样本的应力应变行为、孔隙流体压力变化、体积变化、渗透性和裂纹发展行为的信息。在描述三轴装置之后，介绍了在不同围压（即 2、5、8、10、12、18 和 25 MPa）和 1 MPa 恒定孔隙水压力下对霍克斯伯里砂岩样本进行的一系列不排水三轴试验的结果。在较低的围压下，砂岩表现出更多的脆性特征，而在较高的围压（即大于 18 MPa）下，它表现出更强的延性行为。莫尔-库仑图显示摩擦角随着围压的增加而减小。最大诱导孔隙水压力随着初始有效围压的增加而线性增加。体积应变变化显示出在较低围压下显着的膨胀以及相当大的体积增加。随着围压的增加，渗透率呈指数下降。声发射数据显示，在低围压下测试的样本中，裂纹萌生发生在接近峰值应力的位置，但在较高围压下测试的样本中，裂纹萌生发生在低得多的应力处。
Triaxial testing is a reliable and popular test method used to obtain key properties of rock and soil used in geotechnical design and numerical modelling. Testing equipment should be sufficiently equipped to accurately simulate thein-situstress state and hydrogeological conditions of the specific design region. However, detailed information on the specifications and development of versatile triaxial apparatuses for testing rock to a high degree of accuracy has rarely been reported in the literature. This paper describes details of a triaxial apparatus developed for testing intact and jointed rock. The newly developed apparatus is able to obtain information regarding stress-strain behaviour, pore fluid pressure changes, volume changes, permeability and crack development behaviour of the test specimen. Following the description of the triaxial apparatus, results of a series of undrained triaxial tests performed on Hawkesbury sandstone specimens at different confining pressures (i.e. 2, 5, 8, 10, 12, 18 and 25 MPa) and a constant pore water pressure of 1 MPa, are presented. At lower confining pressures the sandstone showed more brittle characteristics and at higher confining pressures (i.e. greater than 18 MPa) it showed a more ductile behaviour. Mohr-Coulomb diagrams showed a decline in friction angle with increasing confining pressure. Maximum induced pore water pressure was increased linearly with increasing initial effective confining pressure. Volumetric strain variations showed a significant dilation at lower confining pressures with a considerable volume increase. Permeability exponentially decreased with increasing confining pressure. Acoustic emission data revealed that crack initiation occurred close to the peak stress for specimens tested at low confining pressures but it occurred at much lower stresses in specimens tested at higher confining pressures.