Effect of Unloading Rate on the Mechanical Behavior and Fracture Characteristics of Sandstones Under Complex Triaxial Stress Conditions

Zhao, Yu; Bi, Jing; Wang, Chaolin; Liu, Pengfei

doi:10.1007/s00603-021-02515-x

Cited by 100 publications

(30 citation statements)

References 45 publications

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“…(1) Based on the relevant data and assessment criterion, the eigenvalue matrix X and classi cation matrix Y can be determined (2) Determining the attractive domain I ab , range matrix I c d and point value matrix A (3) According to (11) and (12), the relative membership degree can be obtained (4) Determining the weights of di erent indices of the surrounding rock quality based on the entropyweight method (5) Computing the level eigenvalues R according to (19)- (22), then the assessment level of surrounding rock quality can be determined on the basis of the magnitudes of R, if n − 0.5 ≤ H ≤ n + 0.5, then the result is level n (n is positive integer)…”

Section: E Assessment Stepsmentioning

confidence: 99%

“…e support vector machine theory is used to assess the quality of rock mass by Zhao et al [22], and its higher accuracy is improved; besides, the distance discriminant analysis method is applied to determine the classification of surrounding rock quality in the tunnel by Gu et al [23] and Chen and Zhou [24]. Wong et al apply the efficacy coefficient method to destabilization risk assessment of surrounding rocks in the tunnel [25,26].…”

Section: Introductionmentioning

confidence: 99%

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The Application of Variable Fuzzy Sets Theory on the Quality Assessment of Surrounding Rocks

Shao

Gao

et al. 2022

Advances in Materials Science and Engineering

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The quality assessment of surrounding rocks has tremendous influences on engineering construction, so its investigation is significant. The uniaxial compressive strength of rocks σ c , the integrity coefficients of rock mass K V , the conditions of the structural plane S S , the seepage amount of groundwater W , and the intersection angle θ between the axis line and structural plane are selected as the quality assessment index of surrounding rocks at first. Then, the entropy weight-variable fuzzy sets model is introduced. Second, the relative membership degree matrix about the variable fuzzy sets is established, and the weight coefficients are determined based on the entropy weight method. Finally, the fracture behavior level of surrounding rocks is determined using the mean ranking feature value. The conclusions demonstrate that the results obtained based on the variable fuzzy sets method are consistent with the current specification; its accuracy arrives at 80%. Compared with the traditional way, its assessment process has higher reliability and efficiency. So, it could provide a new alternate way to assess the risk level in civil engineering accurately.

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Section: E Assessment Stepsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Application of Variable Fuzzy Sets Theory on the Quality Assessment of Surrounding Rocks

Shao

Gao

et al. 2022

Advances in Materials Science and Engineering

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show abstract

“…e selection of experimental materials must approximate to the roughness of actual materials to reflect the flow regime of the water actually in the spillway. According to the principle of gravity similarity [30], this can be expressed as follows:…”

Section: Fabrication and Installation Of Materialsmentioning

confidence: 99%

The Experimental Investigation of the Optimization of the Flow State of a Ladder-Shaped Spillway in a Certain Reservoir

Zhang

et al. 2022

Geofluids

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The original design scheme of ladder-shaped spillways in certain reservoirs is improved by using a hydraulic similar model experiment. The results of the original scheme demonstrate that the stilling basin cannot meet the requirement of safe discharge, and the flow state at the end of the stilling basin is violent and chaotic. The experimental method of the physical model was used to optimize the design of the spillway without changing the original plane layout. First, three steps in the ladder are added. The stilling basin is then replaced by the torsion plane. Finally, the longitudinal slope of the tail channel section is altered, and an experimental investigation on the flow state and energy dissipation rate is performed. The conclusions are drawn that the flow state of the water is obviously improved, and the energy dissipation rate increases; the optimal scheme produces the expected effects.

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“…The crack propagation evolution of soft rocks under drywet cycles has been a hot research topic [6][7][8]. Soft rock crack initiation, propagation, and coalescence are complex physical, chemical, and mechanical water-rock interaction processes [9][10][11][12], which are closely related to mineral composition, mesostructure, and stress state [13][14][15]. Mineral dissolution and water absorption swelling are important causes of crack initiation and propagation of soft rock [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Evolution Mechanism of Mesocrack and Macrocrack Propagation in Carbonaceous Mudstone under the Action of Dry-Wet Cycles

Huang

Liang

et al. 2022

Geofluids

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The crack propagation evolution of carbonaceous mudstone under the action of dry-wet cycles is an important cause of the unstable failure of this type of slope. This paper attempts to reveal the evolution mechanism of mesocrack and macrocrack propagation in carbonaceous mudstone under the action of dry-wet cycles from chemical, physical, and mechanical perspectives. Firstly, the soaking solution of carbonaceous mudstone during the dry-wet cycles was extracted for an ion concentration test to analyze the chemical reactions of carbonaceous mudstone. Then, CT scans were performed on the carbonaceous mudstone samples to study the changing pattern of mesostructure of carbonaceous mudstone during the dry-wet cycles. In the end, the mechanical properties and failure characteristics of carbonaceous mudstone after dry-wet cycles were studied by triaxial compression tests. The results showed that chemical reactions such as calcite dissolution, potassium feldspar hydrolysis, and sodium feldspar hydrolysis occurred during the dry-wet cycle of carbonaceous mudstone. Affected by the dry-wet cycles, the mesostructure of the carbonaceous mudstone gradually changed from face-face contact and edge-face contact to edge-corner contact and corner-corner contact, and the interlayer flake structure was opened and was locally curled and fractured. With the increase in the number of dry-wet cycles, the failure characteristic of carbonaceous mudstone transformed from tensile failure to shear failure, the failure surface of carbonaceous mudstone was deflected from 90° to 60°, and the crack propagation path of carbonaceous mudstone became more complicated. The chemical reaction of carbonaceous mudstone minerals during the dry-wet cycle is an important reason for the initiation and development of pores. The dry-wet cycle aggregates the propagation of mesocracks and structural disorder, transforming the uniform stress state of the rock mesostructure to the concentrated stress state, which is the important reason for the macrocrack propagation evolution of carbonaceous mudstone.

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Effect of Unloading Rate on the Mechanical Behavior and Fracture Characteristics of Sandstones Under Complex Triaxial Stress Conditions

Cited by 100 publications

References 45 publications

The Application of Variable Fuzzy Sets Theory on the Quality Assessment of Surrounding Rocks

The Application of Variable Fuzzy Sets Theory on the Quality Assessment of Surrounding Rocks

The Experimental Investigation of the Optimization of the Flow State of a Ladder-Shaped Spillway in a Certain Reservoir

Evolution Mechanism of Mesocrack and Macrocrack Propagation in Carbonaceous Mudstone under the Action of Dry-Wet Cycles

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