Effects of seepage-induced erosion on nonlinear hydraulic properties of broken red sandstones

Ma, Dexin; Duan, Hongyu; Li, Xibing; Li, Zhenhua; Zhou, Zilong; Li, Tianbin

doi:10.1016/j.tust.2019.102993

Cited by 180 publications

(96 citation statements)

References 44 publications

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“…The presence of water can markedly alter the mechanical behavior of rock materials [1][2][3][4][5][6][7], which are responsible for a variety of geological disasters such as landslides [8], goaf collapse [9,10] and fault activation [11][12][13]. In many engineering applications such as tunnels, mines, basements and radioactive waste storage, rocks are commonly subjected to water erosion resulting from construction beneath the groundwater table.…”

Section: Introductionmentioning

confidence: 99%

Water-Weakening Effects on the Mechanical Behavior of Different Rock Types: Phenomena and Mechanisms

et al. 2019

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The presence of water strongly affects rock properties and would be related to a series of geological disasters. To understand water saturation effects on the mechanical behavior of different rock types and interpret the underlying mechanisms of differences in water sensitivity, three kinds of rocks, namely sandstone, granite and marble, were selected for tests. Uniaxial compression experiments were conducted on specimens under oven-dried and water-saturated conditions. Acoustic emission (AE) techniques were also applied to monitor and record AE signals during tests. Experimental results reveal that water weakens the mechanical parameters of the three tested rocks, such as uniaxial compressive strength (UCS), elastic modulus and critical strain. The sandstone undergoes the greatest weakening with the addition of pore water, the mechanical properties of the granite exhibit relatively minor reductions, while the marble is the least affected by water saturation. The water-weakening degree of rock properties depends on the porosity as well as the mineralogy, especially the proportion of quartz and swelling clays. Moreover, after water saturation, the failure pattern of the sandstone and the granite tends to transform into the shear-dominant mode from the tensile one in dry state, probably due to frictional reduction. However, the water presence does not change the failure mode of the marble.

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Section: Introductionmentioning

confidence: 99%

Water-Weakening Effects on the Mechanical Behavior of Different Rock Types: Phenomena and Mechanisms

et al. 2019

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“…In previous theoretical studies [11,[15][16][17], K ID is usually set as a constant of rock, but actually, it is a variable and has a linear relationship with loading rate. According to the researches on rock dynamic cracking under various loading rates [50][51][52][53][54][55], the dynamic fracture toughness of rock under blast loading can be written as…”

Section: Advances In Civil Engineeringmentioning

confidence: 99%

Study of the Rock Crack Propagation Induced by Blasting with a Decoupled Charge under High In Situ Stress

Liu

Yang

2020

Advances in Civil Engineering

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The high in situ stress can significantly affect the blast-induced rock fragmentation and cause difficulties in deep mining and civil engineering where the drilling and blasting technique is applied. In this study, the rock crack propagation induced by blasting under in situ stress is first analyzed theoretically, and then a numerical model with a decoupled charge in LS-DYNA is developed to reveal how the initiation and propagation of rock cracks are under high in situ stress. Through simulation, the mechanisms of blast-induced crack evolution under various hydrostatic pressures and nonhydrostatic pressures are investigated, and the differences in crack evolution with specific decoupling coefficients are compared. According to the simulation, three damage zones, i.e., the crushed zone, the nonlinear fracture zone, and the radial crack propagation zone, are formed, and the radial crack evolution is greatly suppressed by the high in situ stress which has no much influence on the crack propagation in the crushed and the nonlinear fracture zones. The velocity of crack propagation is slightly reduced, and the process of crack propagation is stopped early when the rock is subjected to high in situ stress. Furthermore, the numerical analysis indicates that the crack grows preferentially in the direction of maximum principal stress, and the radial crack propagation is predominantly controlled by the preloaded pressure, which is vertical to the crack propagation direction. Based on the numerical results, it is suggested that the optimal decoupling coefficients for rock cracking are 2.65, 1.87, 1.37, and 1.22 for 0, 10, 20, and 30 MPa, respectively. This study provides not only an analysis of the rock crack evolution under high in situ stress but also a reference for resolving excavation difficulties in deep mining.

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“…As is known to all, the flow regime does not conform to the linear Darcy's law under higher fluid flow velocity (higher pressure gradient ∇p) [39][40][41]. In order to further illustrate the non-Darcy flow mechanism of fluid flow through rough fractures and quantify the degree of the nonlinear flow effect, a factor E was proposed by Zeng and Grigg [42]:…”

Section: Critical Grout Hydraulic Gradient and Reynolds Numbermentioning

confidence: 99%

Experimental Investigation of Grout Nonlinear Flow Behavior through Rough Fractures

Jin

Han

et al. 2019

Processes

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This research experimentally analyzed the impacts of various water cement (W/C) ratios of ultrafine cement grout material and normal loads FN applied to fractures on grout nonlinear flow behavior through a rough plexiglass fractured sample. An effective self-made apparatus was designed and manufactured to conduct the stress-dependent grout flow tests on the plexiglass sample containing rough fractures. At each W/C ratio, the grout pressure P increased from 0 to 0.9 MPa, and the normal loads FN ranged from 666.3 to 1467.8 N. The results of the experiments indicate that (1) the Forchheimer’s law can be used to express the results of grout nonlinear flow through rough fractures. Moreover, both nonlinear coefficient a and linear coefficient b in Forchheimer’s law decreased with the increase of the W/C ratio, but increased with the increase of the FN value. (2) For normalized transmissivity, with the increase of Re, the decline of the T/T0–Re curves means that the grout flow behavior through the fracture mainly went through three stages: the viscosity effect, then the weak inertia effect, and finally the strong inertia effect. The three stages showed that with the increase of Re, the grout flow state changed from linear to nonlinear. Moreover, with the increase of the W/C ratio, the Forchheimer coefficient β decreased. (3) At a given FN, the critical grout hydraulic gradient Jc decreased, but the critical Reynolds number Rec increased as the W/C ratio increased; at a given W/C ratio, Jc increased, but Rec decreased as FN increased.

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Effects of seepage-induced erosion on nonlinear hydraulic properties of broken red sandstones

Cited by 180 publications

References 44 publications

Water-Weakening Effects on the Mechanical Behavior of Different Rock Types: Phenomena and Mechanisms

Water-Weakening Effects on the Mechanical Behavior of Different Rock Types: Phenomena and Mechanisms

Study of the Rock Crack Propagation Induced by Blasting with a Decoupled Charge under High In Situ Stress

Experimental Investigation of Grout Nonlinear Flow Behavior through Rough Fractures

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