In the process of coal formation, the internal structure is different from the occurrence of primary cracks. As a result, the new crack generation and primary crack development of different samples are affected to different degrees during loading and unloading. Energy characteristics under true triaxial loading and unloading
WhatsApp: +86 18203695377
The rock mass in fault zones is frequently subjected to cyclic loading and unloading during deep resource exploitation and tunnel excavation. Research on the mechanical and hydraulic characteristics of fault rock during the cyclic loading and unloading is of great significance for revealing the formation mechanism of waterconducting pathways in fault and preventing water inrush disasters. In ...
WhatsApp: +86 18203695377
During the deformation process of coal under the combined highstatic confining pressure and axial disturbance loads, we found that the final instability failure of coal specimens, subjected to disturbance load, were more likely to occur in the disturbance loading and unloading stage, such as specimen SB1, and SD1.
WhatsApp: +86 18203695377
Unloading PRB coal cars with a Dravo rotary dumper
WhatsApp: +86 18203695377
During the process of underground mining, roadway excavation and heading face cause the surrounding rock to produce stress disturbance and break the equilibrium state of coal and rock, which is usually manifested as axial loading and confining pressure unloading. This phenomenon is more obvious during the deep mining of coal and rock.
WhatsApp: +86 18203695377
The repeated mining causes the unloading and loading of the caved zone, so that the pore structures of caved zone change accordingly, and thus affect the permeability value, which controls the gas migration in the caved zone. The main factors affecting the permeability of the unloading process are different from those controlling it during loading.
WhatsApp: +86 18203695377
The working process of the underground coal bunker was actually the loading or unloading of coal for the silo wall. And the stress environment of the silo wall and surrounding rock continually changes, resulting in the deformation of the silo wall under the inner lateral pressure. Stress Analysis
WhatsApp: +86 18203695377
Thus, the axial stress in the experiment is equal to the confining stress. In this study, three loading and unloading seepage tests have been carried out to simulate the effect of three coal seams mining on the caving zone and the second and third loading and unloading stress paths are the same as the first loading and unloading stress path.
WhatsApp: +86 18203695377
In the process of coal seam mining, the coal is disturbed by periodic pressure. This disturbance can be simplified to the loading process under different stress environments [5], [9], [10], [45], and the characteristics of the mining stress path are different under different advancing speeds [46]. Fig. 3 shows the loading path of the sample. M ...
WhatsApp: +86 18203695377
In this paper, the alternate loading and unloading by stages tests of raw coal samples were carried out by using the "Triaxial seepage test device of thermal fluid solid of coal and rock", the conclusions are as follows: The axial strain change rate ε 1 ′, the radial strain change rate ε 3 ′ and the permeability change rate k′ under unit stress state are used to represent the ...
WhatsApp: +86 18203695377
Coal isn't carrying the burden for other commodities anywhere except on the subdivisions that are almost nothing but coal. At present, coal supplies % of electricity, nuclear %, natural gas %, oil %, hydro %, and other sources (mostly biomass, but also wind, geothermal, and solar) about %.
WhatsApp: +86 18203695377
For example, in the loading and unloading process, much elastic energy accumulates in the coal and rock mass with increasing elastic deformation. Under unloading, elastic energy is released. In the test process, the total energy density and elastic energy density of the coal mass can be expressed as Formulas ( 2 ) and ( 3 ).
WhatsApp: +86 18203695377
Mining under the sea is a challenging task in China. Affected by blasting, tunneling, and other engineering disturbance, surrounding rock is often in a state of cyclic loading and unloading stress. In this study, in order to investigate the effect of cyclic loading and unloading on the deformation and damage characteristics of sandstone underneath the Bohai Sea, the GCTS test machine is used ...
WhatsApp: +86 18203695377
The loadingunloading process is represented as follows: 0 ... In cyclic loading process, the coal samples first exhibit the appearance of microcracks at the beginning stage. With the increase in the axial stress, the damage gradually accumulates and produces irreversible plastic deformation. When the peak load is reached, partial area of ...
WhatsApp: +86 18203695377
The effects of repeated loading and unloading paths on the raw coal samples were studied by analyzing the samples' permeability, energy dissipation and AE characteristics. ... During the loading and unloading process, the work done by the effective confining pressure on coal mass is far smaller than that of the axial effective stress ...
WhatsApp: +86 18203695377
The damage in coal cyclic loading was quantitatively characterized by the damage variables and damage constitutive equations based on electrical resistivity. The results show that the response of resistivity and DIC is regular and complementary. ... The results show that during the true triaxial cyclic loading and unloading process, the ...
WhatsApp: +86 18203695377
Coal failure is often the precursor of dynamic disaster. The energy evolution behaviour at different stress values was analysed under the gradation of equal amplitude cyclic loading/unloading. Based on the energy dissipation behaviour, the energy evolution model of the coal specimen was established. The multiparameter energy behaviour predicting model was proposed.
WhatsApp: +86 18203695377
The coils are then loaded either on a reel style or cradle style uncoiling system. Cradle style uncoilers are relatively easy to load, you basically lower your coil onto the cradle, position the sides guides to center the coil and your coil is ready to be released. On a reel type the process is not as easy. You have a large heavy object either ...
WhatsApp: +86 18203695377
Discussion on bulk carrier loading and unloading operations and freight safety for the owner's and master's responsibilities and ... Hu SP, Jin YX, et al. Performance simulation of the transportation process risk of bauxite carriers based on the Markov Chain and Cloud model. J Mar Sci Eng 2019; 7(4): 116. Crossref. Google Scholar. 7. ...
WhatsApp: +86 18203695377
The size effect of coalgangue mass after loading and unloading test is the reflection of its inherent structural complexity, which is due to the existence of fracture network system in rock mass and the joint influence of loading and unloading process. Coalgangue physical and mechanical properties and particle distribution, as well as defects ...
WhatsApp: +86 18203695377
Ship Cargo Handling, Loading, Unloading: A commercial ship is usually a link in a "trade route" between distant points. Goods flowing in the route must be transferred to and from the sea link; they must also be given care while aboard the ship, and in turn they must not be a hazard to the ship and its crew. Ancient cargo handling consisted almost exclusively of manually carrying cargo in ...
WhatsApp: +86 18203695377
In the true triaxial cyclic mechanical experiment of coal, most of the total work done by the three principal stresses is accumulated in the coal with elastic potential energy (the elastic strain energy will be released in the unloading process of external force, approximately equal to the negative work done by the external force in the ...
WhatsApp: +86 18203695377
True triaxial loadingunloading tests of coal samples were performed using a multifunctional true triaxial fluidsolid coupling experimental system. The deformation, seepage, damage, strength, and failure characteristics of the coal samples were analyzed. Based on this, the variation mechanism of the permeability and yield conditions under different gas pressures was investigated, and the ...
WhatsApp: +86 18203695377
A material supplier from Belgium would like to produce limestone powder for his custome...
India is rich in various mineral resources and it is an important mineral processing market
Copyright © 2023 GMC Co., Ltd. SiteMap
