Strength and deformation behavior of red sandstone under multi-stage triaxial compression

2012 ◽  
Vol 49 (6) ◽  
pp. 694-709 ◽  
Author(s):  
Sheng-Qi Yang
Keyword(s):  
Deformation Behavior ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Single Stage ◽  
Peak Strength ◽  
Red Sandstone ◽  
Triaxial Strength ◽  
Multi Stage ◽  
Strength And Deformation ◽  
The Difference

Based on multi-stage triaxial experimental results of red sandstone with circumferential deformation control, the influence of confining pressure on strength and deformation behavior of red sandstone under multi-stage triaxial compression is investigated. The results show that the confining pressure has an obvious effect on the deformation parameters of red sandstone under multi-stage triaxial compression. A multi-stage triaxial compression experiment with only one specimen can be used to confirm the peak strength of rock under different confining pressures. Under single-stage and multi-stage triaxial compression, the peak strength behavior of red sandstone agrees better with the nonlinear Hoek–Brown criterion than the linear Mohr–Coulomb criterion. However, the difference between single-stage and multi-stage triaxial strength changes with different post-peak deformation values, and the reason for the difference, is discussed. To predict single-stage triaxial strength using the obtained multi-stage triaxial strength with only one specimen, a new method is put forward to revise multi-stage triaxial strength of red sandstone, which testifies to being reasonable. The concluding remarks are very useful and significant for deep geotechnical and underground structural engineering.

Study on Constitutive Mode of Three Typical Rocks Based on Triaxial Compression Test

2012 ◽  
Vol 170-173 ◽  
pp. 322-326
Author(s):  
Kui Chen ◽  
Ren Hua Yang ◽  
Tao Xu ◽  
Ya Jing Qi
Keyword(s):  
Residual Strength ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Digital Design ◽  
Peak Strength ◽  
Design Parameters ◽  
Stress Strain ◽  
Red Sandstone ◽  
Constitutive Mode ◽  
Shield Machine

In order to study the relationship between the design parameters of the shield machine and the strength of rock, the behaviours of rocks under the conventional triaxial compression, the complete stress-strain curves under different confining pressures of three typical rocks, i.e. granite, limestone and red sandstone, were taken out for analysis. From the curves, the values of elastic modulus E and Poisson's ratio μ were gained and the relationships between the following parameters were figured out, which are peak strength versus confining pressure, residual strength versus confining pressure, strain at peak strength versus confining pressure, and strain at residual strength versus confining pressure. According to the values and relationships, the complete stress-strain curves were divided into three parts. For each part, a constitutive equation was established by using the strain softening trilinear elastic-brittle-plastic constitutive model, and all the related parameters in the constitutive equations were also presented, which provide a theoretical foundation for the digital design of the cutter head and cutters of Shield machine.

Study on the Engineering Properties of Saturated Red Sandstone

2014 ◽  
Vol 638-640 ◽  
pp. 589-593
Author(s):  
Hong Yi Wang ◽  
Wu Xiu Ding ◽  
Jin Jin Yang
Keyword(s):  
Construction Projects ◽  
Elasticity Modulus ◽  
Triaxial Compression ◽  
Mechanical Damage ◽  
Confining Pressure ◽  
Peak Strength ◽  
Engineering Properties ◽  
Compression Tests ◽  
Red Sandstone ◽  
Slope Excavation

Red sandstone with a strong water softening can cause difficulties of construction projects, especially for slope excavation and support engineering. Therefore, the study on the engineering properties of saturated red sandstone has a important meaning. The mechanical parameters of saturated red sandstone are obtained by the triaxial compression tests. The test results indicate that the ralations between peak strength, elasticity modulus and confining pressure for the saturated specimens are similar with the natural specimens, that is, with the increasing of confining pressure, the peak strength and the elasticity modulus will increase, but the growth rate becomes slowly. Under the same confining pressure, the peak strength and the elasticity modulus of saturated specimen are more smaller than the natural one. The mechanical damage caused by water recedes when the confining pressure increases, so for the geotechnical engineering with larger influence of water, the increasement of confining pressure by the supporting structures is conducive to the stability of rock mass. The research results will provide a theoretical basis for the red sandstone engineering.

scholarly journals Assessment of strength and deformation of lightweight concrete and its components under triaxial compression, taking into account the macrostructure of the material

2021 ◽  
Vol 264 ◽  
pp. 02015
Author(s):  
Chorikul Raupov ◽  
Ulugbek Shermuxamedov ◽  
Anora Karimova
Keyword(s):  
Lightweight Concrete ◽  
Triaxial Compression ◽  
Experimental Studies ◽  
Confining Pressure ◽  
Hardened Cement ◽  
Compression Tests ◽  
Triaxial Strength ◽  
Pressure Parameter ◽  
Strength And Deformation ◽  
Triaxial Compression Tests

The paper presents the results of experimental studies on the strength and deformations of lightweight concrete, mortar matrix and hardened cement paste under triaxial compression. Tests on samples were carried out using short-term triaxial proportional σ1 > σ2 = σ3 loading (i.e. axial compression + lateral hydrostatic pressure). During the loading, the ratio of the main stresses (both axial and lateral) was kept constant up to the end of tests. The experimental studies were carried out for different low ratios of σ2/σ1. A theoretical estimation has been discussed to approximate experimental results and prediction of triaxial strength values for different types of lightweight concrete. An estimation of the confining pressure parameter K has been done for the used mode of loading.

scholarly journals Triaxial Compressive Failure Characteristics and Constitutive Model Study of Jurassic-Cretaceous Weakly Cemented Sandstone

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jinlong Cai ◽  
Wei Zou
Keyword(s):  
Constitutive Model ◽  
Residual Strength ◽  
Triaxial Compression ◽  
Volumetric Strain ◽  
Ductile Failure ◽  
Mathematical Expression ◽  
Confining Pressure ◽  
Mining Area ◽  
Peak Strength ◽  
Correction Coefficient

A conventional triaxial compression test of Jurassic-Cretaceous typical weakly consolidated sandstone from a mining area in Ordos, China, was conducted using an MTS816 tester. Results showed that, before the peak, the rock had a distinct yield stage. When the specimen reached its peak strength, the strength decreased rapidly and showed an obvious brittle failure. When the confining pressure was increased to 15 MPa, the decrease of strength was slow and the rock tended toward ductile failure. With the increase of confining pressure, the cyclic strain initially increased slightly, whereas the volumetric strain increased greatly and the rock sample was in a compression state. When the load reached a critical value, the curve was reversely bent, resulting in volume expansion, whereas the peak strength, residual strength, and elastic modulus increased with confining pressure, and Poisson’s ratio decreased with the confining pressure. In the model based on macroscopic failure rock, the expression of the relationship between fracture angle and confining pressure provided a solid theoretical basis for the direction and failure mode of the macroscopic crack. Based on the rock strength theory and Weibull random distribution assumption of rock element strength, the damage variable correction coefficient was introduced when the residual strength was considered. Then, the mathematical expression of the 3D damage statistical constitutive model was established. Finally, the theoretical curve of the established constitutive model was compared with the triaxial test curve, which showed a high degree of coincidence.

scholarly journals Particle Size Distribution Effects on the Strength Characteristic of Cemented Paste Backfill

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 322 ◽  
Author(s):  
Jiangyu Wu ◽  
Meimei Feng ◽  
Zhanqing Chen ◽  
Xianbiao Mao ◽  
Guansheng Han ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Strength Characteristic ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Peak Strength ◽  
Strength Parameter ◽  
Cemented Paste Backfill ◽  
Paste Backfill

It is of great significance, for economic, environmental and security reasons, to investigate the strength characteristic of underground cemented paste backfill (CPB). Consequently, an ultrasonic test, uniaxial and triaxial compression experiment, and acoustic emission (AE) monitoring were carried out on CPB, for which the particles satisfied Talbot gradation. The homogeneity of CPB specimens was evaluated by ultrasonic pulse velocity (UPV). The stress–strain behavior and AE characteristic of CPB specimens under different Talbot indices and confining pressures were investigated. The effects of the particle size distribution and the confining pressure on the peak strength of CPB were analyzed. The strength parameter model of CPB under the coupled influence of the particle size distribution and the confining pressure was constructed based on the Mohr–Coulomb strength criterion. The results show that the peak strength of CPB is positively linear with confining pressure, however, the relationship between its strength parameters and the Talbot index can be characterized by a quadratic polynomial function. This suggests that there is an optimal gradation of particles reflected in the maximum strength of CPB.

scholarly journals Experimental Investigation on the Evolution of Damage and Seepage Characteristics for Red Sandstone under Thermal-mechanical Coupling Conditions

2021 ◽  
Author(s):  
Haopeng Jiang ◽  
Annan Jiang ◽  
Fengrui Zhang
Keyword(s):  
High Temperature ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Effect Of Temperature ◽  
Permeability Evolution ◽  
Red Sandstone ◽  
Permeability Characteristics ◽  
Mechanical Coupling ◽  
Coupling Conditions ◽  
Rock Stability

Abstract Rock masses in underground space usually experience the coupling of high-temperature field, stress field and seepage field, which gives them complex mechanical behavior and permeability characteristics. In order to study the mechanical properties and permeability characteristics of red sandstone under different temperature environments, a seepage test under high temperature and triaxial compression is carried out based on the RLW-2000 multi-field coupling tester. The results show that the plastic flow of red sandstone at the stress peak under the same temperature is more obvious with the increase of confining pressure. In addition, as the confining pressure gradient increases, the permeability decreases and the trend becomes slower. And the higher the operating temperature, the easier to produce seepage channels inside the rock sample. The development of fissures is rapidly developed under the effect of temperature, so the seepage channels are widened and increased, and the permeability is greatly increased. The constitutive model of rock statistical damage considering the interaction of high temperature and osmotic pressure was constructed based on the experimental data and combining theoretical methods to reveal the characteristics of permeability evolution induced by thermal damage of rocks. The research results can be used as a reference for monitoring rock stability during geological engineering projects involving thermal-seepage-stress coupling conditions.

scholarly journals Experimental Study on the Mechanical Properties and Seepage Characteristics of Red Sandstone with a Single Persistent Joint under Triaxial Compression

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Wei Wang ◽  
Shifan Liu ◽  
Chong Shi ◽  
Shanxi Zheng ◽  
Qizhi Zhu
Keyword(s):  
Mechanical Properties ◽  
Pore Pressure ◽  
Failure Modes ◽  
Shear Failure ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Strengthening Effect ◽  
Red Sandstone ◽  
Inclination Angles ◽  
Seepage Characteristics

In this research, the conventional triaxial compression experiments for intact red sandstone specimens and the specimens with a single persistent joint at different inclination angles, i.e., 0°, 30°, 45°, and 90°, were conducted at first. Based on the results of the conventional tests, the effects of the confining pressure and the joint inclination angle on the mechanical properties including deformation behavior and strength parameters were summarized and analyzed, respectively. We find that the strength and deformation of jointed red sandstone are enlarged due to the increment of confining pressure, and the mechanical parameters of specimens show a U-shaped development with the rise of the joint angle. Besides, to investigate the effects of the pore pressure on seepage characteristics of rocks with joint angles at 0°, 45°, and 90°, a series of triaxial compression drainage tests on the jointed red sandstone were performed. The results show that the pore pressure has a weakening effect on the strength of jointed specimens, which can reduce the strengthening effect induced by confining pressure. Meanwhile, the tested specimens mostly present shear failure modes. As a result, the mechanical responses, seepage characteristics, and cracking modes in red sandstone containing a single persistent joint under triaxial compression are revealed.

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