Study on time-varying characteristics of similar material model strength and the regulation measures

2017 ◽  
Vol 76 (15) ◽  
Author(s):  
Huaizhan Li ◽  
Guangli Guo ◽  
Jianfeng Zha
Keyword(s):  
Material Model ◽  
Time Varying ◽  
Similar Material ◽  
Model Strength

scholarly journals Study on the Strata Movement Rule of the Ultrathick and Weak Cementation Overburden in Deep Mining by Similar Material Simulation: A Case Study in China

2020 ◽  
Vol 2020 ◽  
pp. 1-21 ◽  
Author(s):  
Guojian Zhang ◽  
Guangli Guo ◽  
Yi’nan Lv ◽  
Yaqiang Gong
Keyword(s):  
Material Model ◽  
Failure Pattern ◽  
Central China ◽  
Western China ◽  
Scale Transformation ◽  
Similar Material ◽  
Deep Mining ◽  
Mining Areas ◽  
Sandstone Formation ◽  
Strong Control

In the deep mining areas of western China, there exist ultrathick and weak cementation strata in the overburdens above the Jurassic coal seams, and the overburden lithology is generally moderately a little weaker than the medium-hard strata. Yet, the practical measurement indicates that the surface movement rule in this area displays the specialty that is apparently inconsistent with its lithology, which increases the uncertainty of safe production in coal mines. In this study, the similar material and numerical simulations were conducted to investigate the movement rule and failure pattern of the ultrathick and weak cementation overburden. In addition, the photographing scale transformation-time baseline parallax (PST-TBP) method was used to monitor the similar material model to makeup for the lacks of Xi'an Jiaotong University Digital Close-range Industrial Photogrammetry System (XJTUDP) software. The findings of this study can be summarized as follows. (1) To some extent, the PST-TBP method can makeup for the deficiency of the XJTUDP software because the measurement accuracy of the PST-TBP method is 0.47 mm. (2) The height of the caving zone is approximately 66 m, and the height of the water suture zone is about 112 m, which is obviously larger than that of the medium-hard and soft overburden in eastern-central China. (3) The first breaking span of the immediate roof reaches 120 m, the cyclic fracturing length is about 60 m, and the separation occurred at 43 m and 66 m above the coal seam. (4) The failure pattern of the ultrathick and weak cementation overburden is “beam-arch shell,” and the failure boundary is arch. (5) The Zhidan group sandstone and Jurassic sandstone formations have strong control effects. The Zhidan group sandstone is the main control stratum and the Jurassic sandstone formation is the secondary-control stratum. The research results provide an insight into guiding the safe mining of deep coal in the ultrathick and weak cementation overburden.

Predictive model of overburden deformation: based on machine learning and distributed optical fiber sensing technology

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wenyuan Liu ◽  
Chunde Piao ◽  
Yazhou Zhou ◽  
Chaoqi Zhao
Keyword(s):  
Machine Learning ◽  
Optical Fiber ◽  
Predictive Model ◽  
Material Model ◽  
Prevention Measures ◽  
Similar Material ◽  
Content Type ◽  
Fiber Sensing ◽  
Optical Fiber Sensing ◽  
Distributed Optical Fiber

Purpose The purpose of this paper is to establish a strain prediction model of mining overburden deformation, to predict the strain in the subsequent mining stage. In this way, the mining area can be divided into zones with different degrees of risk, and the prevention measures can be taken for the areas predicted to have large deformation. Design/methodology/approach A similar-material model was built by geological and mining conditions of Zhangzhuang Coal Mine. The evolution characteristics of overburden strain were studied by using the distributed optical fiber sensing (DOFS) technology and the predictive model about overburden deformation was established by applying machine learning. The modeling method of the predictive model based on the similar-material model test was summarized. Finally, this method was applied to engineering. Findings The strain value predicted by the proposed model was compared with the actual measured value and the accuracy is as high as 97%, which proves that it is feasible to combine DOFS technology with machine learning and introduce it into overburden deformation prediction. When this method was applied to engineering, it also showed good performance. Originality/value This paper helps to promote the application of machine learning in the geosciences and mining engineering. It provides a new way to solve similar problems.

Experimental Study on Performance of Pressure Sensor and Similar Material Model

2010 ◽  
Vol 163-167 ◽  
pp. 4537-4541
Author(s):  
Shao Jie Chen ◽  
Bo Li ◽  
Wei Jia Guo
Keyword(s):  
Mechanical Properties ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Material Model ◽  
Repeated Loading ◽  
Pressure Curve ◽  
Test Results ◽  
Similar Material ◽  
Matching Problem ◽  
Similar Materials

In this paper, in order to get the mechanical properties of the different ratio similar material models and resolve the matching problem of pressure sensor and measured similar material, according to the similarity theories, the repeated loading tests on different ratio similar models were performed by multi-stage loading. This paper got the stress-pressure curve and the failure strength of each model. Test results show that there are significant differences in the matching abilities between different ratio similar materials and pressure sensors, and the matching abilities between different models of the same ratio and pressure sensors also have some differences. The matching ability between similar material and pressure sensor should be detected, so as to correct the experimental data. Test results also show that different ratio similar materials have stable and different mechanical properties. The mechanical properties of the similar material can be adjusted appropriately by changing the ratio. The mechanical properties of different ratio similar materials should be tested before the similar material simulation test.

Experimental Study on Self-Made Similar Material of Soft Rock

2016 ◽  
Vol 717 ◽  
pp. 140-146 ◽  
Author(s):  
Jian Guang Li ◽  
Yang Wu ◽  
Yong Yan Wang ◽  
Nan Qin ◽  
Wei Xing Wang
Keyword(s):  
Model Experiment ◽  
Mechanical Characteristics ◽  
Soft Rock ◽  
Material Model ◽  
Similar Material ◽  
Advantages And Disadvantages ◽  
Mixed Mortar ◽  
Cementing Agent ◽  
Physical And Mechanical Characteristics ◽  
The Ideal

Similar material of soft rock used at domestic and abroad are analyzed and compared and researched the advantages and disadvantages of them. Self-made similar material of soft rock mixed with cement, plaster mixed mortar as a cementing agent and sand, rubber powder as aggregate were analyzed and compared. After analyzed multi physical and mechanical characteristics, different ratios of specimens were verified by adjusting the ratio of different materials in similar material to obtain the ideal similar material of soft rock. It was provided reference for similar material model experiment of soft rock.

Experimental Investigation of Simulating Similar Materials of Multi-Seam Mining in Steep

2011 ◽  
Vol 255-260 ◽  
pp. 3765-3769
Author(s):  
Kui Xing Liu ◽  
Xiao Gang Wei ◽  
Shu Xian Liu ◽  
Li Ping Lv
Keyword(s):  
Similarity Index ◽  
Physical And Mechanical Properties ◽  
Material Model ◽  
Prototype Model ◽  
Similar Material ◽  
Initial State ◽  
Deformation And Failure ◽  
Model Method ◽  
Movement And Deformation ◽  
Seam Mining

The similar material model method is used to simulate to the movement of cover rock and ground which is caused by mining underground coal, the substance of deformation and failure law of similar material model method is that artificial materials which are used in the experiment have similar physical and mechanical properties as archetype, affinity constants of geometry, movement and force are used as similarity index and criteria in the simulation experiment as the most important factors. The prototype model is made into a certain proportion model in reduction, and the initial state and boundary conditions of model must be similar as archetype. Then exploit the simulating model, the regular patterns of fault destruction, curve, movement and deformation of cover rock can be discovered in the process of exploiting the simulating model, and the movement and deformation of the surface and its sphere of influence can also be got. Finally the observations of model can be calculated and projections up to the prototype by the similarity index, so the most important regular pattern of the prototype can be got.

Study on Failure of Soft Overburden of Fully Mechanized Top Coal Caving

2012 ◽  
Vol 446-449 ◽  
pp. 2192-2195
Author(s):  
Jin Shan Wang ◽  
Zhong Chang Wang
Keyword(s):  
Abutment Pressure ◽  
Main Roof ◽  
Material Model ◽  
Stress And Strain ◽  
Similar Material ◽  
Coal Face ◽  
Coal Wall ◽  
Internal Stress Field ◽  
Seam Mining ◽  
Step Distance

The similar material model experiment takes the NO.S2S9 coal face in DaPing coal mine as a prototype to research the characteristics of movement and failure of the soft overburden under fully mechanized top coal caving conditions. The abutment pressure distribution and periodic weighting, caving span are given by monitoring the stress and strain in the similar material model. The results show that rocks fracture extended from button with the advance of workface. The first caving step distance of main roof is 34m. The periodic caving step distance of main roof is 10m. The internal stress field is 10m and the peak abutment pressure point is 80m far away from the coal wall, while the disturbance range in anterior coal wall is 200m. Some cracks are closed in the later stage. The advance of around 300m is the distance that the water flowing fractured zone’s height reaches the highest value. The biggest height of water- flowing fractured zone is 140m. The soft overburden has strong plastic deformation capability. The synchronism of failure and movement of overburden is strong. The failured overburden is compacted and the cracks keep close with the advance of workface. The simulation experiment provides a reference bases for the application and promotion of thick seam mining technology.

scholarly journals Surface Subsidence Control Mechanism and Effect Evaluation of Gangue-Backfilling Mining: A Case Study in China

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Huaizhan Li ◽  
Guangli Guo
Keyword(s):  
Surface Deformation ◽  
Material Model ◽  
Simulation Method ◽  
Surface Subsidence ◽  
Deformation Characteristics ◽  
Resource Exploitation ◽  
Similar Material ◽  
Surface Subsidence Control ◽  
Gangue Backfilling ◽  
Overlying Strata

Comprehensive mechanization solid backfilling mining is a new technology developed in China for coal mining and surface subsidence control. Based on a gangue-backfilling project in the Yangzhuang Coal Mine, the characteristics of underlying strata and surface deformation were studied by similar-material simulation method. When the ratio of the sponge to foam was 1 : 3, the mixture can simulate well the deformation characteristics of gangues in the similar-material model. On this basis, the movement and deformation characteristics of the overlying strata caused by gangue-backfilling mining were studied. The findings indicate that compared with caving mining, the expansion coefficient of overlying strata, the interlayer fracture, and the subsidence value were smaller in backfilling mining, with the integral overlying strata subsidence occurring. Meanwhile, the reduction ratio of surface subsidence after backfilling mining was more than 85%, verified by the subsidence-monitoring results. The research outcomes in this paper have significance for coal resource exploitation of similar mines around the world.

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