Research on Failure Characteristics and Zoning Control Technology of Thick-Soft Surrounding Rock for Deep Gob-Side Entry Retaining

Wu, Jing; Zhou, Wenbin; Hong, Tao; Bai, Haowen; Yin, Wei; Gu, Wenhu; Zhang, Peng; Liu, Zejun; Zhang, Jiao

doi:10.1155/2020/6613514

Cited by 6 publications

(6 citation statements)

References 15 publications

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“…(2) e structural characteristics of three kinds of polyurethane/water glass composite grouting materials were analyzed by multiple characterization methods. (3) e foaming and drainage behaviors had little influence on the thermal stability of the grouting material, but they greatly reduced the compressive strength of the material.…”

Section: Discussionmentioning

confidence: 99%

“…With the continuous deepening of coal mining, safety problems including roof fall and rib spalling often appear in the coal working face, which not only greatly reduce the mining efficiency but also threaten the life safety of miners [1][2][3]. Grouting plays an irreplaceable role in strengthening loose and broken coal and rock mass [4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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Effects of Foaming and Drainage Behavior on Structure and Properties of Polyurethane/Water Glass (PU/WG) Grouting Materials for Coal Mines

Liu

Wang

et al. 2021

Advances in Civil Engineering

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During the grouting operation in the underground coal mine, abnormal curing behaviors such as foaming and drainage often lead to the loss of reinforcement effect of the polyurethane/water glass (PU/WG) materials on coal walls and even cause safety accidents. Herein, three kinds of PU/WG grouting materials were successfully prepared by changing the type of catalysts, which were the normal sample (C7), the foaming sample (C14), and the sample with drainage (C17) during curing. The structure, thermal stability, and compressive strength of the three samples were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry-differential thermal analysis (TG-DTA), and pressure testing machine. The results showed that the abnormal curing behavior had little effect on the thermal stability of the material, but it had a significant effect on the microstructure and compressive strength of the consolidated body. C7 exhibited a typical three-phase distribution, in which the polysilicate microspheres encapsulated by acicular carbonate were embedded in the polymer continuum. The structure of C7 had high rigidity and hardness, and the compressive strength was up to 43 MPa. The three-phase structure of C14 disappeared gradually with the increase of catalyst content, the hard block material and matrix are porous, and the compressive strength was only 2.7 MPa. The organic polymer of C17 existed in the form of microsphere and distributed irregularly in the continuum composed of inorganic components, and the compressive strength was 4.9 MPa. The abnormal solidification behavior such as foaming and drainage made the water glass/polyurethane material lose its basic mechanical properties, which cannot meet the needs of grouting reinforcement in coal mines. Therefore, the type of catalyst had a significant impact on the stability of the system, and it is necessary to avoid selecting catalysts that are likely to cause abnormal solidification during formulation research.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Foaming and Drainage Behavior on Structure and Properties of Polyurethane/Water Glass (PU/WG) Grouting Materials for Coal Mines

Liu

Wang

et al. 2021

Advances in Civil Engineering

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“…e specific BP algorithm is derived as follows: suppose the input layer has P neurons [7] and p is any neuron among them; the hidden layer has V neurons, and v is any neuron among them; the output layer has C neurons element, and c is any neuron among them. E pv represents the salience weights of the p-th neuron in the input layer and the v-th neuron in the hidden layer, and E pc represents the salience weights [8] of the p-th neuron in the hidden layer and the v-th neuron in the output layer [9]. e error signal of the p-th neuron in the output layer is…”

Section: Bp Neural Network Learning Algorithmmentioning

confidence: 99%

Research and Control of Underground Pressure Law of Coal Mining Face in Soft Rock Strata Based on Neural Network under the Background of Wireless Network Communication

Rong

Tong

2021

Mobile Information Systems

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Our country has a vast territory and rich resources, but it is a country with more coal, less oil, and poor gas. With the increase of our population, the development of society, and the more severe international situation, coal has become more important for our country’s economic development and energy. Security plays an irreplaceable role. Based on the neural network, this paper studies and controls the underground pressure law of the coal mine’s soft rock heading face, aiming at the safe and efficient mining of the first face and providing an experience for the next face. This paper mainly uses BP neural network learning algorithm and support pressure algorithm to measure and study the ground pressure law of coal mine soft rock heading face and establishes the ground pressure online monitoring system, which is used to analyze and summarize the ground pressure abnormal area during the mining of the working face, so as to provide the basis for safe mining of the working face. Through the field measured data, the initial pressure step and periodic pressure step at the upper, middle, and lower parts of the working face, the average working resistance of the support at the working face during pressure, and the dynamic load coefficient of the support are obtained. It is analyzed that the support in the middle of the working face has a large load and the pressure is obvious. The experimental results show that the initial support force of the whole working face is approximately normally distributed, the proportion of the initial support force in the range of 10–30 MPa accounts for more than 85% of the total statistics, and the frequency of the initial support force in the upper, middle, and lower stations at 10–25 MPa is 55%–65%.

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“…There are many factors affecting the stability of surrounding rock of filling body of gob-side entry retaining. Gu et al (2019) and Wu et al (2020) conducted an experimental study on the roof of gob-side entry retention, and believed that the weak stability of surrounding rock supporting structure and the low lateral cooperative bearing capacity of the roof were the subjective reasons for the deformation and failure of surrounding rock of gob-side entry retention.…”

Section: Analysis Of Influence Factors Of Stabilitymentioning

confidence: 99%

Determination of Reasonable Width of Filling Body for Gob-Side Entry Retaining in Mining Face With Large Cutting Height

Pu¹,

Wu²,

Liu³

et al. 2021

Preprint

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When gob-side entry retaining is adopted in mining face with large cutting height, due to large stope space, strong dynamic pressure and other reasons, the filling body is usually broken and unstable due to improper width of filling body, and the stability of surrounding rock of roadway is poor. Therefore, this paper will take Shaqu mine as the engineering background to study the reasonable filling body width of gob-side entry retaining in mining face with large cutting height. Firstly, the stability factors of gob-side entry retaining in mining face with large cutting height are analyzed, and the mechanical model of bearing structure of gob-side entry retaining is established based on the lateral pressure and overlying load of filling body, and the reasonable width of filling body is obtained quantitatively; Numerical simulation is used to analyze the evolution of vertical stress, vertical displacement and plastic zone of working face with the change of filling body width. Finally, combined with the deformation observation results of 24207 gob-side entry retaining roof, two sides and filling body, the rationality of filling body width is verified. The results show that: the setting of the width and strength of the filling body plays an important role in the stability of gob-side entry retaining. According to the mechanical model, the minimum width of the filling body is 2.2m in the lateral direction and 3.9m in the vertical direction; Numerical simulation shows that when the width of filling body is too small, with the increase of filling body width, the vertical stress of filling body increases gradually. When the width of filling body reaches a certain value, the vertical stress decreases with the increase of width, and the stress concentration area will change from symmetrical type to eccentric load type, from the middle of filling body to the side of filling body near gob. If the width of the filling body is too small, the filling body will be too broken to bear the load, resulting in too small vertical stress and too large vertical displacement of the roadway roof. The larger the width of the filling body is, the greater the cutting resistance is, the more timely the side roof of the gob can be cut off, the less the stress of the roadway and the filling body, and the more stable the retained roadway is. Finally, through the observation of 24207 gob-side entry retaining, the total deformation of two sides and roof and floor of roadway tends to be stable after 665mm and 597mm respectively. The roof of roadway does not appear severe subsidence and obvious cracking, and the floor does not appear too large floor heave. The effect of roadway retaining is good, which indicates that 4m support can meet the needs of practical engineering.

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Research on Failure Characteristics and Zoning Control Technology of Thick-Soft Surrounding Rock for Deep Gob-Side Entry Retaining

Cited by 6 publications

References 15 publications

Effects of Foaming and Drainage Behavior on Structure and Properties of Polyurethane/Water Glass (PU/WG) Grouting Materials for Coal Mines

Effects of Foaming and Drainage Behavior on Structure and Properties of Polyurethane/Water Glass (PU/WG) Grouting Materials for Coal Mines

Research and Control of Underground Pressure Law of Coal Mining Face in Soft Rock Strata Based on Neural Network under the Background of Wireless Network Communication

Determination of Reasonable Width of Filling Body for Gob-Side Entry Retaining in Mining Face With Large Cutting Height

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