Optimization of face flexible bolting and grouting technology for longwall face support under difficult geological conditions

Yang, Shengli; Li, Meng; Song, Gaofeng; Yang, Yi; Xie, Fangwei

doi:10.1002/ese3.591

Cited by 15 publications

(8 citation statements)

References 10 publications

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“…Increasing the concentration of grouting slurry is the simplest and most economical technical method. e main problem that restricts the grouting slurry concentration is that when the slurry concentration is high, it easily precipitates, and the probability of blocking the grouting pipeline increases [27][28][29]. erefore, finding or configuring a grouting liquid with a high concentration, slow sedimentation rate, and good stability is a research topic with important practical value.…”

Section: Study On Selection and Performance Of Separate Layer Grouting Materialsmentioning

confidence: 99%

Performance Research of Materials and Engineering Application of Overburden Strata Separation-Zone Grouting Technology

Huang

Gang

et al. 2022

Advances in Materials Science and Engineering

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To solve the ground subsidence problem associated with thick coal seam mining under the railway in the Tangshan Mine, the technology of overburden strata separation-zone grouting (OSSG) was proposed. Based on the analysis of the full height overlying strata structure in the range of the six working face areas of the second mining district, the spatial distribution characteristics of the separation zone within the overlying strata are obtained after fully mining the six working faces. Then, emphasis was placed on the selection ratio of grouting materials and the hydrodynamic properties of different grout types, and grouting grout with a high concentration, slow precipitation rate, and good stability was obtained by taking fly ash and local clay as aggregates. The designed grout concentration was approximately 40%; the bulk density was approximately 1.20; and the clay content in the aggregates was approximately 40–50%. The separation-zone grouting plan was designed for the six working faces, and continuous grouting technology with the characteristics of multiple separation zones within the full-height section with a large flow and a high concentration was proposed to form a complete grouting system and reasonable grouting process. After engineering verification, the technology has an ash injection ratio of 24.2%, a grouting ratio of 100.3%, and a reduction in the ground subsidence ratio of 51.5%, effectively reducing mining damage to the ground surface and ensuring the safe operation of ground surface railways. Simultaneously, this advancement improves the resource recovery rate of coal mines and provides greater benefits for mining enterprises.

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Section: Study On Selection and Performance Of Separate Layer Grouting Materialsmentioning

confidence: 99%

Performance Research of Materials and Engineering Application of Overburden Strata Separation-Zone Grouting Technology

Huang

Gang

et al. 2022

Advances in Materials Science and Engineering

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“…An important way to solve this issue is the grouting of the fractured rock mass. Grouting substances including chemical and cementitious materials can fill the mining-induced cracks and voids and bind the fractured rock properly, thereby turning the loose weak rock mass into a strong solid material [ 40 ]. Therefore, the grouting of the surrounding rock can be divided into two subgroups: high, when the surrounding rock is broken but not grouted; and low, when the surrounding rock is broken and grouted.…”

Section: Parameters Contributing To Ground Instabilitymentioning

confidence: 99%

Assessment of ground instability risk of lower seam longwall panels during crossing overlying remnant pillars

Pan

Wang

et al. 2020

R. Soc. open sci.

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One of the most challenging safety problems is ground instability during crossing overlying remnant pillars (CORP). Ground instability not only causes injury to miners or fatalities, but also leads to interruptions in the mining operations and breakdowns in equipment. In this paper, 12 major parameters influencing the ground instability were firstly determined based on extensive international experience associated with CORP. The consequences of the ground instability were then assessed in terms of miners' health and financial losses. Afterwards, a practical method to assess the ground instability risk of lower-seam longwall panels during CORP was developed based on its probability and consequence. Finally, this method was successfully used to determine the best scheme for CORP of LW10-103 at Mugua coal mine. The main advantage of this method is that it enables mining engineers to easily use international experience for assessing the risk of ground instability and selecting reasonable supports during CORP.

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“…(ii) study on the effects of external load, that is, considering the stress state (tension, compression, shear), loading, unloading, and the creep of the bolt according to the engineering site [11,12]; (iii) study on the effects of the nature of the bolt itself, such as type, size (diameter, length), row spacing, pretightening force, and the spatial distribution position of multiple bolts [13][14][15][16][17][18]. Some contributed results have been obtained: in terms of the bolting mechanisms, Kang [19,20] considered that the main function of bolt support on surrounding rock is to control the separation, sliding, cracking, and dilatancy deformation of rock mass in the anchorage zone and put forward the corresponding key bearing ring theory.…”

Section: Introductionmentioning

confidence: 99%

Experiment and Numerical Simulation of Strength and Stress Distribution Behaviors of Anchored Rock Mass in a Roadway

Zhao

Qin

et al. 2023

Geofluids

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Due to the influence of the ground stress, mining disturbance, and other factors, the roadway surrounding rock in deep underground engineering such as mines, tunnels, and underground caverns is prone to looseness and deformation with the excavation of roadways. In such engineering, the bolt support is frequently employed to stabilize the surrounding rock. In this work, a part of the anchor and the surrounding rock were taken as a simplified model of the anchorage rock mass, and the laboratory compression test was performed on the similitude model. Then, the FLAC3D software was used to simulate varying numbers of bolts and different lateral pressure conditions, and the peak stress, the maximum principal stress field, and the anchor stress field distribution of the anchorage rock mass were obtained. The influence of bolt pretightening force and row spacing on the stability of surrounding rock was discussed using the combined arch theory. The results show that increasing the number of bolts and lateral pressure in the anchorage rock mass can significantly improve the stress value and distribution range of the maximum principal stress field and the anchorage stress field. The fluctuation of the anchorage stress field at different anchorage distances can be lessened by increasing the number of bolts (bolt density). When the lateral pressure exceeds 3 MPa, the anchorage mechanical characteristics of the anchorage rock mass tend to remain stable. The coverage of the effective anchorage stress field and the thickness of the surrounding rock anchorage composite arch can be increased by increasing the bolt pretightening force and decreasing row spacing, consequently improving the anchorage mechanical characteristics of the anchorage rock mass. The research results can be used as a theoretical reference for choosing appropriate bolt support parameters for the roadway surrounding rock.

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Optimization of face flexible bolting and grouting technology for longwall face support under difficult geological conditions

Cited by 15 publications

References 10 publications

Performance Research of Materials and Engineering Application of Overburden Strata Separation-Zone Grouting Technology

Performance Research of Materials and Engineering Application of Overburden Strata Separation-Zone Grouting Technology

Assessment of ground instability risk of lower seam longwall panels during crossing overlying remnant pillars

Experiment and Numerical Simulation of Strength and Stress Distribution Behaviors of Anchored Rock Mass in a Roadway

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