Effect of inclined interface angle on shear strength and deformation response of cemented paste backfill-rock under triaxial compression

2021 ◽  
Vol 279 ◽  
pp. 122478
Author(s):  
Wu Weilv ◽  
Wenbin Xu ◽  
Zuo Jianpin
Keyword(s):  
Shear Strength ◽  
Triaxial Compression ◽  
Cemented Paste Backfill ◽  
Deformation Response ◽  
Paste Backfill ◽  
Strength And Deformation

Shear Strength of a Cemented Paste Backfill Submitted to High Confining Pressure

2016 ◽  
Vol 858 ◽  
pp. 219-224 ◽  
Author(s):  
Eduardo Eiler Batista de Araújo ◽  
Dragana Simon ◽  
Fagner Alexandre Nunes de França ◽  
Osvaldo de Freitas Neto ◽  
Olavo Francisco dos Santos Jr.
Keyword(s):  
Shear Strength ◽  
Triaxial Compression ◽  
Binder Content ◽  
Cemented Paste Backfill ◽  
Compression Tests ◽  
Mining Operations ◽  
Geomechanical Properties ◽  
Confining Pressures ◽  
Paste Backfill ◽  
Curing Method

Deep mining operations require special measures in order to keep safe and economic aspects. After mine ore is extracted, voids are created and need to be filled with high-strength, low-cost materials. Cemented Paste Backfill (CPB) has recently become one of the main alternatives in filling stopes. Although numerous papers have mentioned the magnitudes of the strength of this material, its behavior under high confining pressures is still not well understood. Therefore, the purpose of this study is to increase the knowledge regarding the CPB behavior. Triaxial compression tests were performed using a Hoek Cell and Load Frame System under high confining pressures. Samples with two different binder contents were used in order to obtain the CPB strength improvement. Besides the self-weight consolidation curing method, samples were subjected to a different curing method that simulated a zero gravity condition (rotating wheel) in the first curing day to compare their mixture properties. The results suggested that both curing method and binder content have influenced the geomechanical properties of Cemented Paste Backfill. By increasing the curing time, the CPB shear strength has increased slightly, whereas specimens with higher binder content presented a significant increase in shear strength values.

scholarly journals Experimental Investigation on Mechanical Properties of Cemented Paste Backfill under Different Gradations of Aggregate Particles and Types and Contents of Cementing Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Jiangyu Wu ◽  
Meimei Feng ◽  
Guansheng Han ◽  
Xiaoyan Ni ◽  
Zhanqing Chen
Keyword(s):  
Mechanical Properties ◽  
Cemented Paste Backfill ◽  
Compression Tests ◽  
Deformation Properties ◽  
Paste Backfill ◽  
Strength And Deformation ◽  
Cementing Material ◽  
Optimal Strength ◽  
Ae Signals ◽  
Aggregate Particles

Obtaining the optimal gradation of aggregate particles is beneficial for improving the strength of cemented paste backfill (CPB). Consequently, the uniaxial compression tests with acoustic emission (AE) monitoring were performed on CPB, for which the aggregate particles satisfied the Talbot grading theory. The effects of the Talbot indices of aggregate particles and types and contents of cementing materials on the mechanical properties of CPB were analyzed. The AE characteristics and stress-strain behaviors of CPB were discussed. The results show that the specific Talbot index reflected the optimal strength and deformation properties of CPB is 0.45, and the maximum UCS is 7.6 MPa. The mechanical properties of CPB also can be optimized by changing the type of cementing material and increasing the content of cementing material. The effects of the Talbot indices of aggregate particles and types and contents of cementing materials on the crack damages reflected by the AE signals of CPB are mainly observed in the oa stage and ab stage during the loading process.

scholarly journals Particle Size Distribution Effects on the Strength Characteristic of Cemented Paste Backfill

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 322 ◽  
Author(s):  
Jiangyu Wu ◽  
Meimei Feng ◽  
Zhanqing Chen ◽  
Xianbiao Mao ◽  
Guansheng Han ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Strength Characteristic ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Peak Strength ◽  
Strength Parameter ◽  
Cemented Paste Backfill ◽  
Paste Backfill

It is of great significance, for economic, environmental and security reasons, to investigate the strength characteristic of underground cemented paste backfill (CPB). Consequently, an ultrasonic test, uniaxial and triaxial compression experiment, and acoustic emission (AE) monitoring were carried out on CPB, for which the particles satisfied Talbot gradation. The homogeneity of CPB specimens was evaluated by ultrasonic pulse velocity (UPV). The stress–strain behavior and AE characteristic of CPB specimens under different Talbot indices and confining pressures were investigated. The effects of the particle size distribution and the confining pressure on the peak strength of CPB were analyzed. The strength parameter model of CPB under the coupled influence of the particle size distribution and the confining pressure was constructed based on the Mohr–Coulomb strength criterion. The results show that the peak strength of CPB is positively linear with confining pressure, however, the relationship between its strength parameters and the Talbot index can be characterized by a quadratic polynomial function. This suggests that there is an optimal gradation of particles reflected in the maximum strength of CPB.

scholarly journals Study on Microstructural Evolution and Strength Growth and Fracture Mechanism of Cemented Paste Backfill

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Jian-Xin Fu ◽  
Wei-Dong Song ◽  
Yu-Ye Tan
Keyword(s):  
Residual Strength ◽  
Mass Fraction ◽  
Solid Phase ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Cemented Paste Backfill ◽  
X Ray Diffraction ◽  
Pressure Peak ◽  
Paste Backfill ◽  
Curing Age

The relations among the uniaxial compressive strength of cemented paste backfill (CPB) with solid phase mass fraction, cement sand ratio, and curing age were studied. The UCS of CPB samples increased exponentially with the increase of solid phase mass fraction and curing age but increased linearly with the increase of cement sand ratio. The results of X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that the strength was determined by the amount of ettringite and C-S-H gelling. With the increase of ettringite and C-S-H gelling, the strength became larger. The triaxial compression test was conducted by selecting four kinds of CPB samples. The results showed that, with the increase of confining pressure, peak and residual strength became larger, but the elastic modulus decreased. When the ratio of confining pressure and uniaxial strength is about 1 : 2, the CPB samples show significant ductility characteristics and the ratio of residual strength and peak strength increased obviously.

Behavior of a Sandy Silt Reinforced with Discontinuous Recycled Fiber Inclusions

2000 ◽  
Vol 1714 (1) ◽  
pp. 9-17 ◽  
Author(s):  
J. J. Murray ◽  
J. D. Frost ◽  
Y. Wang
Keyword(s):  
Shear Strength ◽  
Axial Strain ◽  
Triaxial Compression ◽  
Value Added ◽  
Strength Loss ◽  
Dry Density ◽  
Compression Tests ◽  
Maximum Dry Density ◽  
Deformation Response ◽  
Sandy Silt

Laboratory compaction and triaxial compression tests were performed to assess the compaction characteristics and load deformation response of a sandy silt reinforced with randomly oriented recycled carpet fibers. Discrete, randomly distributed fiber inclusions significantly increase the peak shear strength, reduce the postpeak strength loss, increase the axial strain to failure, and, in some cases, change the stress-strain behavior from strain softening to strain hardening for a sandy silt. Fiber inclusions also impede the compaction process, causing a reduction in the maximum dry density of reinforced specimens with increasing fiber content. The strength losses associated with in-service saturation are significantly reduced with fiber reinforcement. It is suggested that large volumes of recycled waste fibers can be used as a value-added product to enhance the shear strength and load deformation response of soils.

scholarly journals Shear Properties of Cemented Paste Backfill under Low Confining Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Andrew N. Pan ◽  
Murray W. F. Grabinsky ◽  
Lijie Guo
Keyword(s):  
Shear Strength ◽  
Mining Industry ◽  
Binder Content ◽  
Environmental Benefits ◽  
Direct Shear ◽  
Cemented Paste Backfill ◽  
Curing Time ◽  
Confining Stress ◽  
Strain Property ◽  
Paste Backfill

Cemented paste backfill (CPB) plays an important role in the mining industry due to safety, cost efficiency, and environmental benefits. Studies on CPB have improved the design and application of paste backfill in underground mines. Direct shear is one of the most fundamental parameters for assessing backfill strength. This study harnesses direct shear tests to explore the low confining stress behavior of CPB. We perform all the tests in a standard apparatus on the combination of three binder contents of 4.2%, 6.9%, and 9.7% CPB with four curing times of 3, 7, 14, and 28 days, respectively. The applied confining stress levels vary in a range according to the in situ regime. Results are presented by strength envelope, stress-strain property, and shear strength with curing time and binder content. The data suggest that the shear strength follows the Mohr–Coulomb envelope in which the shear strength and behavior are time and binder content dependent. In addition, the results show that shear strength is strongly related to the binder content than the curing time, namely, the higher the degree of binder hydration, the higher the cementation binding force between CPBs.

scholarly journals An Experimental Study on Shear Strength of Cemented Paste Backfill Materials

2017 ◽  
Vol 22 (1) ◽  
pp. 45
Author(s):  
Eren KÖMÜRLÜ ◽  
Alp TURAN ◽  
Ferdi CİHANGİR ◽  
Ayhan KESİMAL ◽  
Bayram ERÇIKDI
Keyword(s):  
Experimental Study ◽  
Shear Strength ◽  
Cemented Paste Backfill ◽  
Backfill Materials ◽  
Paste Backfill

scholarly journals Experimental Investigation on Strength and Failure Characteristics of Cemented Paste Backfill

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhihong Zhang ◽  
Jiacheng Li
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Uniaxial Compressive Strength ◽  
Cement Content ◽  
Confining Pressure ◽  
Curing Temperature ◽  
Cemented Paste Backfill ◽  
Upward Trend ◽  
Paste Backfill ◽  
Curing Age

The strength characteristics of cemented paste backfill (CPB) in mining areas are key control factors for the safety assessment of overlying strata. A series of experiments about uniaxial compression and triaxial compression were carried out to study the influence of cement content of filling slurry, curing age, and curing temperature on strength behavior of CPB specimens. The failure mechanism and damage feature of CPB have been investigated. The results show the following: (1) The uniaxial compressive strength of CPB specimens exhibits an upward trend with the increase of cement content and curing age. When the cement content is high, the uniaxial compressive strength increases sharply with increasing curing age. (2) The cohesion of CPB specimens increases with the increase of cement content of filling slurry, curing age, and curing temperature. The cohesion of CPB specimens with curing age 7 days and 14 days increases linearly with increasing cement content. At the later stage of curing age, the strength growth of high cement content backfill is significantly greater than that of low cement content. The internal friction angle of the filling increases slightly with increasing filling cement content, curing age, and curing temperature. (3) The shear strength of CPB specimens at curing age 7 days exhibits an upward trend with the increase of confining pressure, while the shear strength at 14 days and 28 days curing age decreases slightly as the confining pressure increases. (4) With the increase of cement content in backfill, the brittleness increases significantly when the backfill is damaged. The failure mode of CPB specimens changes from monoclinic section shear failure to X-type failure with increasing curing age, and the failure process is divided into four stages: pore compaction, linear elastic deformation, plastic deformation, and post-peak failure.

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