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  1. Article ; Online: Investigating the Mechanism of Continuous–Discrete Coupled Destabilization of Roadway-Surrounding Rocks in Weakly Cemented Strata under Varying Levels of Moisture Content

    Lihui Sun / Zhixin Jiang / Yaxin Long / Qingfeng He / Haiyang Zhang

    Processes, Vol 11, Iss 2556, p

    2023  Volume 2556

    Abstract: This study examines frequent disasters, including large-scale deformation and collapse, caused by underground mining in weakly cemented strata in Western China. The weakly cemented rock’s unique characteristics, including low strength and easy ... ...

    Abstract This study examines frequent disasters, including large-scale deformation and collapse, caused by underground mining in weakly cemented strata in Western China. The weakly cemented rock’s unique characteristics, including low strength and easy disintegration, demonstrate a different damage pattern than that traditionally seen in the central and eastern regions. Using Fast Lagrangian Analysis of Continua-Particle Flow Code (FLAC2D-PFC2D) coupling, we model the strata, focusing on the 3-1 coal seam roadway at Hongqinghe mine. This study investigates the damage–rupture–destabilization progression in the peripheral rock under varying levels of moisture content. Our findings indicate that a water content of ω = 5.5% is the threshold for roadway damage, and moisture content <5.5% yields minimal rock deformation. However, moisture content >5.5% abruptly increases cracks and shifts the rock’s force chain, causing significant deformation and affecting the ceiling the most. Moreover, higher levels of moisture content weaken the anchor solid’s performance, with two primary failure modes: anchor interface slippage (comprising five stages: elasticity, elasticity–shear hardening, elasticity–shear hardening–decohesion, shear hardening–decohesion, and decohesion) and shear damage. These insights are vital for improving numerical simulations of underground mining, obtaining a more accurate understanding of mineral pressure disasters in weakly cemented strata mining regions in Western China, and developing a solid foundation for the better control of such strata.
    Keywords continuous–discrete ; moisture content ; weakly cemented rock ; destabilization mechanism ; anchorage failure mechanism ; Chemical technology ; TP1-1185 ; Chemistry ; QD1-999
    Subject code 669
    Language English
    Publishing date 2023-08-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Effect of Loading Rate on the Mechanical Properties of Weakly Cemented Sandstone

    Lihui Sun / Yaxin Long / Xing Li / Zhixin Jiang / Yu Fan / Zongze Wang / Xiangang Han

    Sustainability, Vol 15, Iss 2750, p

    2023  Volume 2750

    Abstract: Weakly cemented rocks are characterized by low strength, loose structure, and easy disintegration. High-intensity mining activities can damage and rupture such rock bodies and induce damage, such as flaking and roofing on roadways. To reveal the mining ... ...

    Abstract Weakly cemented rocks are characterized by low strength, loose structure, and easy disintegration. High-intensity mining activities can damage and rupture such rock bodies and induce damage, such as flaking and roofing on roadways. To reveal the mining intensity influence on the weakly cemented rocks’ deformation and damage, a numerical particle flow model of weakly cemented sandstone was established based on particle flow theory. Uniaxial compression simulation tests were conducted at four loading rates of 0.01, 0.1, 0.5, and 1 mm/min to study the weakly cemented sandstone’s stress–strain relationship, damage rupture, acoustic emission, and energy evolution. The results show that, with an increased loading rate, the uniaxial compressive strength of weakly cemented sandstone increases exponentially, and the rupture mode transforms from brittle damage to ductile damage; the greater the loading rate, the greater the degree of damage and crushing range of the rock. Further, with an increased loading rate, the peak hysteresis of rock acoustic emission events decreases, and the number of events increases; the energy accumulated in the rock increases, thus intensifying the degree of rock damage. Therefore, the possibility of engineering disasters should be considered when conducting high-speed underground mining activities.
    Keywords particle discrete element ; loading rate ; acoustic emission characteristics ; uniaxial compression ; mechanical properties ; Environmental effects of industries and plants ; TD194-195 ; Renewable energy sources ; TJ807-830 ; Environmental sciences ; GE1-350
    Subject code 621
    Language English
    Publishing date 2023-02-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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    Inter-library loan at ZB MED

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  3. Article ; Online: Cyclic Loading and Unloading of Weakly Consolidated Sandstone with Various Water Contents

    Yaxin Long / Lihui Sun / Zhenyu Cai / Zhixin Jiang / Zongze Wang / Qingfeng He / Zhong Bai

    Sustainability, Vol 15, Iss 13866, p

    2023  Volume 13866

    Abstract: Weakly cemented rocks have a loose structure, poor mechanical properties, and soften and disintegrate upon contact with water. Mining operations cause damage and ruptures to rocks under cyclic loading and unloading, leading to serious disasters. This ... ...

    Abstract Weakly cemented rocks have a loose structure, poor mechanical properties, and soften and disintegrate upon contact with water. Mining operations cause damage and ruptures to rocks under cyclic loading and unloading, leading to serious disasters. This study investigated the effects of cyclic loading and unloading on the mechanical properties of weakly cemented sandstone (WCS) with various water contents (0–7.72%). A numerical model based on the particle flow theory simulated the behavior of WCS particles. The stress–strain relationships, damage and rupture patterns, energy evolution, and damage properties of WCS were examined using loading–unloading simulations. Water negatively affected the strength and elastic modulus of WCS. High water contents (>2.31%) increased the rupture probability and affected the rupture modes. Ruptures mainly occurred via the main fissure and caused cleavage damage; however, instances of tensile damage and shear slippage increased with an increasing water content. The elastic, dissipation, and total energies gradually increased with increasing cyclic loading and unloading. The damage factors of WCS with different water contents gradually increased with the growth rate. The mechanical properties of the sandstone were deteriorated by water, which increased the peak value of the damage factor from 0.77 for 0% moisture to 0.81 for 7.72% moisture.
    Keywords weakly cemented rocks ; water content ; cyclic loading and unloading ; energy evolution ; damage coefficient ; Environmental effects of industries and plants ; TD194-195 ; Renewable energy sources ; TJ807-830 ; Environmental sciences ; GE1-350
    Subject code 690
    Language English
    Publishing date 2023-09-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

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