Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Publication
- Publication Type
Articles 1 - 6 of 6
Full-Text Articles in Engineering
Fracture Feature Recognition Of Sandstone After High Temperature Based On Ra/Af, Ge Zhenlong, Sun Qiang, Wang Miaomiao, Zhao Chunhu
Fracture Feature Recognition Of Sandstone After High Temperature Based On Ra/Af, Ge Zhenlong, Sun Qiang, Wang Miaomiao, Zhao Chunhu
Coal Geology & Exploration
It is of great significance to carry out the research on rock high temperature damage information identification for geothermal development and underground coal gasification. Based on the changes of acoustic emission parameters RA and AF in the failure process of sandstone after different high temperature treatments, the development and evolution law of different types of cracks in sandstone after high temperature treatment are studied. The results show that tensile cracks are dominant in the whole loading process of sandstone. When the loading stress exceeds 80% of the peak stress, the proportion of shear cracks increases rapidly, which can be regarded …
Stress-State And Injection-Rate Dependent Damage Processes During The Hydraulic Fracturing Of Granite, Gayani Sasendrika Gunarathna
Stress-State And Injection-Rate Dependent Damage Processes During The Hydraulic Fracturing Of Granite, Gayani Sasendrika Gunarathna
Dissertations
Hydraulic fracturing is a well-stimulation technique that is employed in field applications, such as enhanced geothermal systems (EGS) and shale oil/gas extraction. This research experimentally investigates the effect of the state of stress and injection rate on the hydraulic fracturing processes. In addition, a displacement discontinuity method (DDM) code, FROCK, is used to model the crack initiation and propagation in a granite specimen under hydraulic fracturing conditions. In order to conduct the experimental work, a test setup capable of applying a triaxial state of stress and water pressure inside pre-fabricated flaws cut in prismatic granite specimens is developed. Additionally, the …
Numerical Simulation Of Propagation Law Of Pore-Fracture Under Uniaxial Stress, Guo Xiucheng
Numerical Simulation Of Propagation Law Of Pore-Fracture Under Uniaxial Stress, Guo Xiucheng
Coal Geology & Exploration
in order to study the law of crack propagation under different pore-fracture conditions, the crack propagation process, acoustic emission law and stress-strain curve under different crack inclination angle and different heterogeneous coefficient were numerically simulated by using RFPA software. At the same time, the results are compared with the experimental results. The results show that the cracks of the intact specimen are produced along the shear direction, while the cracks of the specimens with pores occur along the side of the crack tip and the orifice. The secondary cracks in horizontal direction and bifurcation at the prefabricated crack tip or …
Numerical Simulation Of Rupture Process Of Shale Under Action Of Fluid-Solid Coupling, Lou Yili, Wu Zhonghu, Wang Anli, Zuo Yujun, Liu Hao, Sun Wenjibin
Numerical Simulation Of Rupture Process Of Shale Under Action Of Fluid-Solid Coupling, Lou Yili, Wu Zhonghu, Wang Anli, Zuo Yujun, Liu Hao, Sun Wenjibin
Coal Geology & Exploration
In order to investigate the rupture process and acoustic emission characteristics of shale under fluid-solid coupling, the numerical simulation of fluid-solid coupling of the Niutitang Formation shale in different bedding angle in the northern part of the Qianbei area was carried out by RFPA2D-Flow numerical software. Studies have shown that due to the influence of the bedding structure, the compressive strength and elastic modulus of shale show obvious anisotropy. The rupture process of shale can be divided into three stages: elasticity, yielding and destruction. With the change of the bedding angle, the shale finally showed three failure modes, namely oblique …
Study On Uniaxial Compression Mechanical Properties Of Sandstone With Different Moisture Content And Wave Velocity Method, Duan Tianzhu, Ren Yaping
Study On Uniaxial Compression Mechanical Properties Of Sandstone With Different Moisture Content And Wave Velocity Method, Duan Tianzhu, Ren Yaping
Coal Geology & Exploration
In order to investigate the mechanical properties and damage of sandstone under different uniaxial compression, the static uniaxial compression tests of five sandstones with different moisture content were carried out, and the physical and mechanical parameters were obtained. And the wave velocity of the sandstone samples with different moisture content were measured by ultrasonic detector. Then the sandstone was loaded to 80% peak intensity and then unloaded to 0. The acoustic wave velocity of sandstone was measured at this time. The damage was determined by acoustic wave method. The results show that the peak strength of sandstone under uniaxial compression …
Acoustic Emission Test Of Calcareous Sands Under Undrained Condition, Yang Chao, Wang Kai, Qiao Liping, Meng Qingshan, Wang Ren
Acoustic Emission Test Of Calcareous Sands Under Undrained Condition, Yang Chao, Wang Kai, Qiao Liping, Meng Qingshan, Wang Ren
Coal Geology & Exploration
Calcareous sand acoustic emission was tested under undrained condition to study the law of acoustic emission with different confining pressure, shear rate, initial void ratio and grading. The results showed that when the confining pressure was lower than 400 kPa, calcareous sand acoustic emission event rate increased with confining pressure. But when the confining pressure was increased to 800 kPa, calcareous sand acoustic emission event rate decreased. The test of calcareous sand was divided into particle breakage stage and particle slip stage in low shear rate. Two stages can't be distinguished clearly as the shear rate increases. Loose and dense …