Rock analysis to characterize Saudi soft sandstone rock

Almisned, Omar A.; Alqahtani, Naif B.

doi:10.1007/s13202-021-01160-y

Cited by 6 publications

(3 citation statements)

References 10 publications

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“…Te results of laboratory tests show that the failure strain of mudstone is 0.018-0.02, and of the coal is 0.012-0.016 (Figure 3). Tis corresponds with the results of testing soft rock specimens in a volumetric feld [36][37][38] and under uniaxial compression [39,40]. According to the results of tests, it was found that for mudstone, siltstone, argillite, and sandstone with uniaxial strength of 25-40 MPa, the failure criteria for strain is about 0.02-0.03.…”

Section: Simulation Resultssupporting

confidence: 72%

Numerical Studies of Floor Heave Control in Deep Mining Roadways with Soft Rocks by the Rock Bolts Reinforcement Technology

Sakhno

2023

Advances in Civil Engineering

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The floor heave is one of the key factors that can restrict high-efficiency and safety mining, especially in the deep roadways with soft rock. Considering the influences of rock fracturing over time on rock mass properties, a case study of the floor heave evolution and rock bolts reinforcement technology was performed in this paper. A numerical simulation was used to study the stress-strain state and displacement of surrounding rocks. It was found that significant floor heave caused by nonlinear deformation of laminated immediate floor under an increase in rock fracturing. The post-peak strain regions appear in the bottom corners of the roadway, after which strata in the immediate floor are destroyed one by one. The joint spacing of 0.45 m on the immediate floor is critical. At this step, post-peak strain regions merge in the central part of the roadway floor, which is the cause of uncontrolled floor heave. Rock bolts reinforcement was proposed to control the floor heave. Three floor support schemes with two types of support elements, different bolt orientations, and lengths of reinforcement were studied. The numerical simulation demonstrated that after reinforcement, post-peak plastic strain in the floor strata was reduced effectively. The optimal floor support scheme and depth of reinforcement were determined by the allowable floor heave. Ideally, the floor heaves could be reduced by rock bolts with a steel belt installed according to the support scheme III and reinforcement length of 2.0 m for outer bolts and 3.0 m for central bolts.

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Section: Simulation Resultssupporting

confidence: 72%

Numerical Studies of Floor Heave Control in Deep Mining Roadways with Soft Rocks by the Rock Bolts Reinforcement Technology

Sakhno

2023

Advances in Civil Engineering

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“…The results of rock specimen tests show [52][53][54][55] that for mudstone, siltstone, argillite, and sandstone with a uniaxial strength of 25-40 MPa, the failure criterion for strain is about 0.02-0.03. Therefore, in the numerical simulation, the post-peak limit was accepted in the range of "−0.02"-"+0.02".…”

Section: Simulation Resultsmentioning

confidence: 99%

Floor Heave Control in Gob-Side Entry Retaining by Pillarless Coal Mining with Anti-Shear Pile Technology

Sakhno,

Skrzypkowski

et al. 2024

Applied Sciences

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The severe floor heave in gob-side entry retaining is the major restriction factor of the wide application of pillarless mining thin coal seams. Reinforcement and stress-relief floor heave control methods are the most promising. However, in practice, floor restoration is widely used. Therefore, floor heave control technology in gob-side entry retaining needs to be improved. This study proposes anti-shear pile technology to control floor heave in gob-side entry retaining. The research was mainly carried out by numerical simulation. It was found that the transformation of high vertical stresses in the entry floor underneath the filling wall and coal seam body into horizontal stresses starts the floor heave process. The vertical dilatancy of rocks under the roadway span and their subsequent unloading lead to the delamination of the floor strata and uplift of the entry contour. In this paper, the best pile installation scheme was found. It is a 2pile 5+2 scheme with the installation of two piles, each 2 m long. After that, it was shown that filling piles are more than 3.3 times cheaper than comparable analogs, and pile installation is less labor-intensive. The implementation of the proposed floor heave control method leads to a reduction in heaving by 2.47 times.

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“…According to the results of testing soft rocks specimen in a volumetric field [34][35][36] and under uniaxial compression [37][38][39][40][41], it was found that for mudstone, siltstone, argillite, shale, and sandstone with a strength of 25-40 MPa, the failure criteria for strain is about 0.03. The surfaces of elastic and plastic strains are shown in Figure 6.…”

Section: Resultsmentioning

confidence: 99%

Numerical Modeling of Controlling a Floor Heave of Coal Mine Roadways with a Method of Reinforcing in Wet Soft Rock

Sakhno

Skyrda

et al. 2022

Geofluids

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A floor heave is usually a serious failure phenomenon in mine roadways, especially in the conditions of a wet soft rock. There are bright prospects for using a method of reinforcing for controlling a floor heave in mine roadways under a dramatic heave. In the current research, a floor heave mechanism in the wet soft rock of mine roadways was investigated while the moisture content of the rocks was increasing. That was done by performing numerical simulations in a finite element analysis software system Ansys and by reinforcing the floor in the shape of inverted arch. It was found that a decrease in the modulus of elasticity of rocks caused by saturation leads to a nonlinear increase in a floor heave. This can be explained by the fact that rocks of the floor become plastic strains. A stable correlation was established between water content and a floor heave of a wet rock. It was found that when the floor is reinforced, the proportion of plastic strains in the soil is significantly reduced. The growth of the modulus of elasticity of rocks in the reinforced zone, caused by reinforcing of the floor in the form of inverted arch, leads to a nonlinear decrease of a floor heave. The effective range of floor reinforcing was established. A reliable relation was established between the ratio of the modulus of elasticity of rocks of the reinforced zone to the modulus of elasticity of the surrounding rock and heaving of reinforced rocks. The obtained results can be used to predict the magnitude of heaving of rocks at their saturation, as well as after they are reinforced.

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Rock analysis to characterize Saudi soft sandstone rock

Cited by 6 publications

References 10 publications

Numerical Studies of Floor Heave Control in Deep Mining Roadways with Soft Rocks by the Rock Bolts Reinforcement Technology

Numerical Studies of Floor Heave Control in Deep Mining Roadways with Soft Rocks by the Rock Bolts Reinforcement Technology

Floor Heave Control in Gob-Side Entry Retaining by Pillarless Coal Mining with Anti-Shear Pile Technology

Numerical Modeling of Controlling a Floor Heave of Coal Mine Roadways with a Method of Reinforcing in Wet Soft Rock

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