Shear Behavior of the Interface Between Rock and Cemented Backfill: Effect of Curing Stress, Drainage Condition and Backfilling Rate

Fang, Kun; Fall, Mamadou

doi:10.1007/s00603-019-01909-2

Cited by 69 publications

(14 citation statements)

References 44 publications

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“…Uniaxial compressive strength (UCS) of CPB has been studied quite extensively (e.g., Kesimal et al (2005); Klein and Simon (2006); Orejarena and Fall (2010); Yi et al (2015); Gorakhki and Bareither (2017); and Xu et al (2018)), in part because it is the least resource intensive, but also because there are many limit equilibrium design methods that depend on UCS as a key input (e.g., Mitchell et al (1982) and Potvin et al (2005)). Less attention has been paid to tests that study mechanical properties and effects of cemented bond breakage on the behavior of cured CPB under more complex loading conditions (Pierce et al 1998;Yilmaz et al 2010;Yilmaz et al 2015;Fang and Fall 2020;Jafari et al 2020a;Jafari et al 2020b). Therefore, new information about CPB's response to high confining pressures is needed.…”

Section: Introductionmentioning

confidence: 99%

Predicting the Isotropic Volumetric Compression Response of Hydrating Cemented Paste Backfill (CPB)

Jafari

Grabinsky

2021

Preprint

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Deep and high-stress mining results in stress transfers onto the previously placed backfill, and mines have recorded several MPa induced backfill stress. Understanding the backfill-rock mass interaction is therefore critical. Previous work considered tabular ore bodies undergoing primarily one-dimensional compression and showed how the backfill reaction curves could be estimated from oedometer laboratory test results. This work considers massive orebodies and develops a similar approach based on isotropic compression curves. Isotropic compression tests exceeding 6 MPa are carried out on samples with 3.0–11.1% binder content, tested at 1-day cure time to 28-day cure time. The compression curve is characterized in three stages: initial elastic compression up to a yield point, followed by a transition stage to the start of a final stage with a linear post-yield compression line in \({\epsilon }_{v}-\text{l}\text{o}\text{g}\left({p}^{\text{'}}\right)\) space. Because these isotropic compression tests are rare (the reported results are the first for Cemented Paste Backfill), attempts are made to relate the isotropic compression test parameters to parameters from the more commonly used Unconfined Compression Strength (UCS) tests. Unifying equations as functions of binder content and cure time are found to determine the initial yield stress and the peak strength from UCS tests. These are then related to the corresponding parameters in isotropic compression. Finally, the slope of the post-yield compression line is found as a function of UCS, thereby enabling complete reconstruction of the isotropic compression response based on parameters from carefully controlled UCS tests, as functions of binder content and cure time. Although the calibrated parameters are specific to the studied mine’s materials, the framework is general and applicable to other mines’ CPBs.

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Section: Introductionmentioning

confidence: 99%

Predicting the Isotropic Volumetric Compression Response of Hydrating Cemented Paste Backfill (CPB)

Jafari

Grabinsky

2021

Preprint

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“…At present, most of the related research focuses on the mechanical properties of surrounding rock and backfill. For example, Fang and Fall [24] studied the shear mechanical properties of the interface between backfill and a rock mass. The characteristics of the mechanical interaction between backfill and a rock mass under the condition of creep behaviour were investigated by Qi and Fourie [25].…”

Section: Introductionmentioning

confidence: 99%

A New Decision Method of Filling Ratio Based on Energy Matching of Surrounding Rock and Backfill

Zhou

Lin

2020

Geofluids

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In order to simplify the ratio decision process of cemented backfill in underground mines and achieve fine decision of filling ratio, the research on the energy matching between surrounding rock and cemented backfill in underground mines was conducted in this study. Based on the cubic function strength model of cemented backfill, the peak specific energy equation of backfill was improved by inversion analysis of the data of filling ratio experiment, and the functional relationship between the peak specific energy and the filling ratio was obtained by regression analysis. Then, based on the energy balance principle between the deformation energy released by the excavation of the underground rock mass and the peak specific energy of the cemented backfill, considering the physical and mechanical parameters of the surrounding rock of the goaf, including bulk density, elastic modulus, and burial depth, a ratio decision model of cemented backfill is established. The application results suggested that the calculation result of the model is reliable, and it can realize the rapid and accurate decision of the ratio of cement backfill in underground mines.

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“…Therefore, a better understanding of this arching effect, especially the shear behavior of the CPB-rock interface, allows for the design of a more economic and safer CPB structure. Few experimental studies have been performed to investigate the shear behavior of the CPB-rock interface [4,20,[26][27][28][29][30]. These studies have mainly concentrated on the external conditions, such as the normal stress, curing time, curing temperature, and sulfate attack.…”

Section: Introductionmentioning

confidence: 99%

“…(1) To study the effect of the initial sulfate concentration on the behavior of a 1-day-old FR-CPB and rock interface; (2) To evaluate the effect of treatment time and the initial sulfate concentration on the behavior of the FR-CPB and rock interface (1-, 3-, 7-, and 28-day-old interface); (3) To compare the effect of the initial sulfate concentration on the interface behavior of FR-CPB material with various fiber contents (after 7 days of curing); Few experimental studies have been performed to investigate the shear behavior of the CPB-rock interface [4,20,[26][27][28][29][30]. These studies have mainly concentrated on the external conditions, such as the normal stress, curing time, curing temperature, and sulfate attack.…”

Section: Introductionmentioning

confidence: 99%

“…The main sources of sulfate ions include the oxidation of sulfur-containing tailings (e.g., FeS 2 , CuFeS 2 , ZnS, and PbS), the use of mine processed tailwater as the mixing water, the oxidation of cyanide (particularly in some gold mines), and the insertion of some additives such as gypsum or anhydrite to decrease the setting time [7]. To the best of our knowledge, there are a lot studies on the effect of fiber [33][34][35][36][37][38][39] and the sulfate [7,9,10] content on the CPB, and the shear behavior of the CPB/rock interface [26][27][28][29][30] has been researched. Nevertheless, no investigations have been conducted on the shear behavior of FR-CPB and the rock interface considering the influence of sulfate attack.…”

Section: Introductionmentioning

confidence: 99%

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Sulfate-Dependent Shear Behavior of Cementing Fiber-Reinforced Tailings and Rock

2020

Minerals

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A better understanding of the shear behavior of the interface between cemented paste backfill (CPB) and the surrounding rock is critical for constructing cost-effective, durable, and reliable CPB structures. In practice, CPBs suffer sulfate attack during their service life, and as a typical cementitious material, the CPB itself has disadvantages, such as high brittleness, easy cracking, and insufficient durability, which restrict the further popularization and application of CPB technology. Thus, in this study, direct shear tests, electrical conductivity (EC) and thermal gravity/differential thermal gravimetric (TG/DTG) analyses were conducted to research the effects of different amounts of monofilament polypropylene fibers (0%, 0.1%, 0.3%, and 0.5%; by mass of the sum of the dry tailings and cement) and initial sulfate concentrations (0 mg/L, 5000 mg/L and 25,000 mg/L) on the shear behavior of the fiber-reinforced CPBs and rock (FR-CPB/rock) interface, and the Mohr–Coulomb shear envelop was used to fit the shear strength of specimens with various periods (1 day, 3 days, 7 days, and 28 days) under various stresses (50 kPa, 100 kPa, 150 kPa). The experimental testing results indicated that the fibers generally enhance the performance of the shear behavior of the FR-CPB/rock interface and the optimal fiber content correlates to the initial sulfate concentration. For the same treatment time (7 days), a fiber content of 0.1% contributes to the best shear performance for the FR-CPB/rock interface with a sulfate concentration of 5000 mg/L. For the sulfate-free and 25,000 mg/L concentration specimens, 0.3% is the optimal fiber content. Furthermore, for the studied interface specimens, sulfate content can play a positive (the refinement of the pore structure) or negative (the sulfate retardation effect) role in the interface shear behavior between the FR-CPB and rock, depending on the treatment time, the initial sulfate concentration, and the fiber content. For the specimens treated for 7 days and 28 days, the specimens with initial sulfate concentrations of 5000 mg/L and 25,000 mg/L achieved the highest peak shear strengths, respectively. The outcomes of this paper present a substantial reference for the design and optimization of underground FR-CPB structures under sulfate attack.

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Shear Behavior of the Interface Between Rock and Cemented Backfill: Effect of Curing Stress, Drainage Condition and Backfilling Rate

Cited by 69 publications

References 44 publications

Predicting the Isotropic Volumetric Compression Response of Hydrating Cemented Paste Backfill (CPB)

Predicting the Isotropic Volumetric Compression Response of Hydrating Cemented Paste Backfill (CPB)

A New Decision Method of Filling Ratio Based on Energy Matching of Surrounding Rock and Backfill

Sulfate-Dependent Shear Behavior of Cementing Fiber-Reinforced Tailings and Rock

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