Open-access original data for the paper of 'Laboratory Investigation on Water-induced Shear Weakening Behaviors of Sandstone Roughness-walled Joints'

This is shear vs. shear displacement experimental data for roughness-walled sandstone joints under different immersed duration. those sandstone is obtained from Three Gorges Reservoir area, China. Many cubic sandstone samples with dimensions of 100×100×100 mm3 were split to obtain artificial tensile joints. Within generated joints, three pairs of joints with different roughness were selected as prototypes to be replicated, which marked as JA, JB and JC. A joint surface replication method combining 3D optical scanning and 3D rigid engraving technology was applied to produce rock joints with same surface morphology. The joint specimens were fully immersed in distilled water at room temperature (about 20℃) for different durations (30, 180, 360 days, respectively). Five joint specimens were tested at each immersion duration. The specimens were coated with waterproofing membranes after remove specimens from water to minimize water loss. As a comparison, five untreated joint specimens were used to determine dry shear behavior. Hence, a total of 60 specimens for JA, JB and JC groups were tested by direct shear tests. The PH value of used distilled water is about 6.98, which is neutral solution. Direct shear tests on joints were performed using CNL&CNS rock joint shear system at Institute of Rock and Soil Mechanics (Wuhan), China. The system is mainly composed of load and control unit, hydraulic unit, data acquisition system. During the test process, two loading modes can be used, constant normal loading and constant normal stiffness, and the maximum normal and tangential loading pressure can be applied for 200 KN and 300 KN respectively. It has an advantage of simple operation, high precision, convenient installation and uninstallation. The shear box with dimension of 100×100×100 m3 was adopted in shear tests. Five joint specimens for each immersion duration were subjected to five different normal stress, 1.0 MPa, 2.0 MPa, 3.0 MPa, 4.0 MPa and 5.0 MPa, respectively. When the joint specimen was ready to be tested, normal and shear preloading was carried out and the normal stress was held in stable condition. The normal load was then applied to the specified value at a rate of 0.1 kN/s and remained unchanged. Finally, the shear load was applied to the specimen at a loading rate of 0.5 mm/min. Once shear displacement reached to 10 mm, shear loading finished. From those data, it is shown that shear process is distinguished by three stages in entire curves for dry and immersed joints. Further analyzing shear displacement, the peak shear displacement up is no more than 3.0 mm for all tests. The average peak shear displacements immersed for 30, 180 and 360 days are smaller than that for dry sandstone joints.

本数据集为不同浸水时长下，粗糙壁面砂岩节理的剪切力-剪切位移试验数据。所用砂岩取自中国三峡库区。制备多组尺寸为100×100×100 mm³的立方体砂岩试样，通过劈裂法获得人工拉伸节理。从生成的节理中选取三组不同粗糙度的节理作为原型，复刻得到试样，分别标记为JA、JB、JC。采用结合三维光学扫描与三维刚性雕刻技术的节理面复刻方法，制备得到表面形貌一致的岩石节理试样。将节理试样置于室温（约20℃）的蒸馏水中分别浸水30、180、360天，每组浸水时长设置5个平行试样。试样从水中取出后，即刻喷涂防水膜以减少水分流失。同时设置5个未浸水的空白试样，用于测定干燥状态下的剪切特性。综上，JA、JB、JC三组共计60个试样均完成直剪试验。所用蒸馏水的pH值约为6.98，呈中性。节理直剪试验在中国武汉岩土力学研究所的CNL&CNS型岩石节理剪切系统上完成。该系统主要由加载控制单元、液压单元与数据采集系统组成。试验过程中可采用两种加载模式：常法向加载与常法向刚度加载，系统最大法向与切向加载荷载分别可达200 kN与300 kN。该系统具备操作简便、精度高、装拆便捷的优势。剪切试验采用尺寸为100×100×100 mm³的剪切盒。每组浸水时长的5个试样分别施加5级不同的法向应力：1.0 MPa、2.0 MPa、3.0 MPa、4.0 MPa与5.0 MPa。试样正式试验前，先进行法向与剪切预加载，使法向应力达到稳定状态。随后以0.1 kN/s的速率施加法向荷载至设定值并保持恒定。最后以0.5 mm/min的加载速率施加剪切荷载，当剪切位移达到10 mm时，停止剪切加载。试验数据表明，干燥与浸水状态下的节理剪切力-位移全过程曲线均可分为三个阶段。进一步分析剪切位移可知，所有试验的峰值剪切位移均不超过3.0 mm；浸水30、180、360天试样的平均峰值剪切位移均小于干燥砂岩节理试样。