This RYE_2021__DATA_README.txt file was generated on 2022-07-27 by Dongming Zhang GENERAL INFORMATION 1. Title of Dataset: Data from: Failure and deformation characteristics of shale under true triaxial stress loading and unloading under water retention and seepage. 2. Author Information Corresponding Investigator Name: Zhang Dongming Institution: ChongQing University, Chongqing, China Email: zhangdm@cqu.edu.cn 3. Date of data collection: 2020-2021 4. Geographic location of data collection: Chongqing, China 5. Funding sources that supported the collection of the data: Scientific Research Foundation of State Key Lab of Coal Mine Disaster Dynamics and Control. (Project Approval Number: 2011DA105287-zd201804) 6. Recommended citation for this dataset: Zhang Dongming, (2022), Data from: Failure and deformation characteristics of shale under true triaxial stress loading and unloading under water retention and seepage. DATA & FILE OVERVIEW 1. Description of dataset All data were obtained through laboratory tests.These data were generated to investigate the stress and strain variation of shale under different experimental conditions.A multifunctional true triaxial fluid-structure coupling system was used to conduct water retention and seepage tests of shale under true triaxial loading and unloading stress paths. The stress-strain evolution law of shale specimens under different experimental conditions was obtained, and the corresponding deformation and strength law was analyzed. The evolution law and failure characteristics of cracks in shale were obtained by CT scanning images before and after the experiment. The results show that under the condition of water retention, the volumetric strain of shale specimen increases first, then decreases and finally continues to increase with the increase of deviational stress, indicating that the volumetric change has experienced a process of compaction-expansion-compacting. The partial stress-maximum horizontal strain curve of the sample increases first and then decreases, while the deformation of the sample in the direction of intermediate principal stress shows the characteristics of repeated compression and expansion. In the seepage test, the permeability - maximum horizontal strain curve can be divided into two parts before and after fracture according to the deviant stress - maximum horizontal strain curve. Before fracture, the compression velocity of the specimen in the loading direction exceeds the expansion velocity in the unloading direction, resulting in a decrease in volume and a decrease in permeability. With the increase of deviatoric stress, cracks occur inside the particles and continue to spread from the tip until the cracks break through the shale specimen. In this process, the pore fissure area increases and the permeability of the sample increases rapidly. In terms of fracture evolution, for the water-retaining test, dense tensile and shear cracks appear on the failure plane perpendicular to the direction of maximum and minimum principal stress, and complex shear fracture network appears on the failure plane perpendicular to the direction of intermediate principal stress. For the seepage test, heavy shear failure occurs throughout the original fracture of the sample. With the increase of the penetration depth, the crack shape on the failure surface perpendicular to the direction of intermediate principal stress gradually changes from single type to complex type. 2. File List: File 1 Name: Date _1.xlsx File 1 Description: 'Deviatoric stress-strain curves of shale specimens under different water pressures' and 'Comparison of deviator stress-strain' File 2 Name: Date _2.xlsx File 2 Description: Relationship between deviatoric stress flow and volumetric strain. File 3 Name: Date _3.xlsx File 3 Description: The relationship between water pressure and flow rate. File 4 Name: Date _4.xlsx File 4 Description: 'Stress and permeability - strain curve' and 'Deviatoric stress-volumetric strain-time curve of the sample' File 5 Name: Date _5.xlsx File 5 Description: Mogi-Coulomb and Drucker-Prager guideline fitting curves. METHODOLOGICAL INFORMATION The shale rock samples used in this study were taken from Yunnan Kunyang phosphate mine with a burial depth of 200 m. The selected shale was analyzed by X-ray diffraction test for its internal composition. the main components of the shale sample used in this experiment are NaAlSiO4. The water retention and seepage test of shale under true triaxial loading and unloading stress path adopts the "multi-functional true triaxial fluid-structure coupling experimental system" independently developed by Chongqing University.The experimental device includes true three-axis pressure chamber, hydraulic oil pressure system, water or gas seepage system, true three-axis frame and disassembly platform guide rail, pressure, displacement and flow data monitoring system, AE signal monitoring system and so on. DATA-SPECIFIC INFORMATION FOR: Date _1.xlsx 1. Number of variables: 4 2. Number of rows: Figure 5a 6a, 391; Figure 5b 6b, 268; Figure 5c 6c, 268 3. Variable List: ε1: ε1 is the strains in the maximum stress direction ε2: ε2 is the strains in the intermediate stress direction ε3: ε3 is the strains in the minimum stress direction σ: σ is the stress 4. Missing data codes: None 5. Abbreviations used: None 6. Other relevant information: There are three data groups Figure 4a 5a, Figure 4b 5b and Figure 4c 5c DATA-SPECIFIC INFORMATION FOR: Date _2.xlsx 1. Number of variables: 4 2. Number of rows: 7ab 2MPa: The variable t, 396; The variable εV and σ 268; The variable V, 29 7ab 3MPa: The variable t, 478; The variable εV, 292; The variable σ, 299; The variable V, 30 3. Variable List: t: t is the time εV: εV is the volumetric strain σ: σ is the stress V: V is the volume of flow through the water-retaining sample 4. Missing data codes: None 5. Abbreviations used: None 6. Other relevant information: There are two data groups 6ab 2MPa and 6ab 3MPa DATA-SPECIFIC INFORMATION FOR: Date _3.xlsx 1. Number of variables: 4 2. Number of rows: Figure 8a:39 Figure 8b:28 Figure 8c: The variable t1 and σ1, 478; The variable t2 and V, 32 3. Variable List: V: V is the volume of flow through the water-retaining sample 4. Missing data codes: None 5. Abbreviations used: None 6. Other relevant information: There are three data groups Figure 7a, Figure 7b and Figure 7c DATA-SPECIFIC INFORMATION FOR: Date _4.xlsx 1. Number of variables: 6 2. Number of rows: 399 3. Variable List: ε1: ε1 is the strains in the maximum stress direction ε2:ε2 is the strains in the intermediate stress direction σ: σ is the stress k: k is the experimental parameters t: t is the time εV:εV is the volumetric strain 4. Missing data codes: None 5. Abbreviations used: None 6. Other relevant information: There are one data group Figure 9 10 DATA-SPECIFIC INFORMATION FOR: Date _5.xlsx 1. Number of variables: 2 2. Number of rows: 4 3. Variable List: I: I is the invariants of stress J:J is the invariants of stress skewness 4. Missing data codes: None 5. Abbreviations used: None 6. Other relevant information: There are two data groups Figure 11a and Figure 11b