Research on the influence of bottom expanding and filling on bolt sliding instability and supporting effect

AbstractThe extracellular matrix (ECM) naturally surrounds cells in humans, and therefore represents the ideal biomaterial for tissue engineering. ECM from different tissues exhibit different composition and physical characteristics. Thus, ECM provides not only physical support but also contains crucial biochemical signals that influence cell adhesion, morphology, proliferation and differentiation. Next to native ECM from mature tissue, ECM can also be obtained from the in vitro culture of cells. In this study, we aimed to highlight the supporting effect of cell-derived- ECM (cdECM) on adipogenic differentiation. ASCs were seeded on top of cdECM from ASCs (scdECM) or pre-adipocytes (acdECM). The impact of ECM on cellular activity was determined by LDH assay, WST I assay and BrdU assay. A supporting effect of cdECM substrates on adipogenic differentiation was determined by oil red O staining and subsequent quantification. Results revealed no effect of cdECM substrates on cellular activity. Regarding adipogenic differentiation a supporting effect of cdECM substrates was obtained compared to control. With these results, we confirm cdECM as a promising biomaterial for adipose tissue engineering.

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Catastrophic Analysis of Seismic Response of Gravity Dam Sliding along Base Surface

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.311-313.2164 ◽

2011 ◽

Vol 311-313 ◽

pp. 2164-2168

Author(s):

Dun Ben Sun ◽

Qing Wen Ren

Keyword(s):

Weibull Model ◽

Gravity Dam ◽

Stable Region ◽

Instability Mechanism ◽

Gravity Dams ◽

Base Surface ◽

Instability Problem ◽

Nonlinear Constitutive Model ◽

Hysteresis Phenomena ◽

Sliding Instability

For the instability problem of gravity dam sliding along base surface, cubic nonlinear constitutive model of soft material in base surface is adopted, which is usually expressed by Weibull model. Dynamic Equations of dam sliding along base surface is established. By means of catastrophe theory, the jumping and hysteresis phenomena of the vibration amplitude of the dam is analyzed, the parameter range of stable region in which amplitude doesn’t happen catastrophe is given and the factors which cause amplitude instability are discussed. The results obtained in the paper are of significant value for understanding the sliding instability mechanism of gravity dam under earthquake, as well as guiding the design of gravity dams.

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The Rationality of Compiling a Forest Resource Balance Sheet

Forest Products Journal ◽

10.13073/fpj-d-21-00022 ◽

2021 ◽

Vol 71 (4) ◽

pp. 309-321

Author(s):

Lijun Jin ◽

Meng Lin ◽

Guoshuang Tian

Keyword(s):

Balance Sheet ◽

Forest Products ◽

Theory And Practice ◽

Practical Significance ◽

Accounting System ◽

Forest Resource ◽

Balance Sheets ◽

Service Value ◽

Supporting Effect ◽

Resource Accounting

Abstract The existing forest resource accounting system is limited to the valuation of wood and forest products; the service value of the forest resource ecosystem is not yet included. This study adopts an empirical approach to studying the rationality and influencing factors of compiling a forest resource balance sheet (FRBS). An FRBS can systematically reflect the contribution of forest resources to the economy, ecology, and society in terms of both physical quantity and value quantity. A questionnaire survey was used to collect the data. We found that the determination and measurement of forest resource assets and liabilities and the calculation of the service value of the ecosystem had a supporting effect on the rationality of compiling an FRBS. This study expands the field and scope of forest resource accounting, facilitates the compilation of natural resources and government balance sheets, and presents the practical significance for the theory and practice behind the development of an FRBS.

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Tunnel Squeezing Deformation Control and the Use of Yielding Elements in Shotcrete Linings: A Review

Materials ◽

10.3390/ma15010391 ◽

2022 ◽

Vol 15 (1) ◽

pp. 391

Author(s):

Xiaomeng Zheng ◽

Kui Wu ◽

Zhushan Shao ◽

Bo Yuan ◽

Nannan Zhao

Keyword(s):

High Resistance ◽

Review Paper ◽

State Of The Art ◽

Squeezing Ground ◽

Deformation Control ◽

Development History ◽

Ground Conditions ◽

Supporting Effect ◽

Mechanical Performances ◽

Shotcrete Lining

Shotcrete lining shows high resistance but extremely low deformability. The utilization of yielding elements in shotcrete lining, which leads to the so-called ductile lining, provides a good solution to cope with tunnel squeezing deformations. Although ductile lining exhibits great advantages regarding tunnel squeezing deformation control, little information has been comprehensively and systematically available for its mechanism and design. This is a review paper for the purpose of summarizing the development history and discussing the state of the art of ductile lining. It begins by providing a brief introduction of ductile lining and an explanation of the importance of studying this issue. A following summary of supporting mechanism and benefits of ductile lining used in tunnels excavated in squeezing ground conditions is provided. Then, it summarizes the four main types of yielding elements applied in shotcrete lining and introduces their basic structures and mechanical performances. The influences of parameters of yielding elements on the supporting effect are discussed and the design methods for ductile lining are reviewed as well. Furthermore, recommendations for further research in ductile lining are proposed. Finally, a brief summary is presented.

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Research on Supporting Countermeasure of B103W01 Transport Roadway in Shajihai Coal Mine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.401-403.2221 ◽

2013 ◽

Vol 401-403 ◽

pp. 2221-2225

Author(s):

Shu Jiang Zhao

Keyword(s):

Coal Mine ◽

Deformation Mechanism ◽

Soft Rock ◽

Single Type ◽

Engineering Practice ◽

Deformation And Failure ◽

Constant Resistance ◽

Supporting Effect ◽

Deformation Mechanics ◽

Coupling Support

For the soft rock roadwaysupporting problems, using the conventional methods cannot effectively controlthe deformation and failure. This paper took B103W01 transport gateway projectin Shajihai coal mine as example and analyzed its deformation failure reasonand deformation mechanism and determined the specific measures of transformingcompound mechanism of deformation mechanics into a single type. In the end, weput forward coupling support technology of constant resistance and largedeformation bolt + hollow grouting anchor + corner grouting steel pipe, whichhad been applied to engineering practice. The monitoring results showed thatthe supporting effect was good. So it can be used for reference for the similarconditions of roadway supporting.

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Evaluation of the Active Support and Yielding Bearing Properties of Artificial Pillars Supporting a Stope Roof Using 3DEC Numerical Simulation

Advances in Civil Engineering ◽

10.1155/2019/5934360 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7

Author(s):

Kunmeng Li ◽

Yuanhui Li ◽

Hongdi Jing

Keyword(s):

Numerical Simulation ◽

Support Effect ◽

Load Shedding ◽

Initial Support ◽

Supporting Effect ◽

Simulation Results ◽

Lower Magnitude ◽

Yielding Support ◽

Pattern Simulation

Before achieving yielding support with artificial pillars, it is significant to evaluate their active support and passive bearing performances on the stope roof. This paper focuses on three aspects of research using 3DEC numerical simulation, which are support patterns of artificial pillars, magnitude of support stresses, and the magnitude of prestresses of the load-increasing yielding support pattern. Simulation results show that the superior sequence of supporting effect is load-increasing yielding support, load-shedding yielding support, and constant and nonyielding support under the same initial support stress. When the magnitude of support stress or the magnitude of prestress is larger with load-increasing yielding support, the supporting effect is superior and the load-increasing yielding support with a lower magnitude of support stress is superior to some other support patterns with higher magnitude of support stresses. The active support can improve the support effect compared with no prestress, and under the same final support stress, the support effect is superior when the roof stress releases more in the early supporting stage regardless of the prestress.

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Thermal Instability of Sliding and Oscillations Due to Frictional Heating Effect

Journal of Tribology ◽

10.1115/1.3261577 ◽

1988 ◽

Vol 110 (1) ◽

pp. 69-72 ◽

Cited By ~ 7

Author(s):

I. L. Maksimov

Keyword(s):

Thermal Instability ◽

Initial Conditions ◽

Frictional Heating ◽

Interface Temperature ◽

Heating Effect ◽

Stick Slip ◽

Instability Development ◽

The Stability ◽

Sliding Dynamics ◽

Sliding Instability

The stability of sliding has been studied, taking into account frictional heating effect and friction coefficient dependence upon the interface temperature and sliding velocity. The collective—thermal and mechanical—sliding instability has been found to exist; instability emergence conditions and dynamics (both in linear and nonlinear stages) have been determined. It is shown that both the threshold and the dynamics of thermofrictional instability differ qualitatively from the analogous characteristics of “stick-slip” phenomenon. Namely, the oscillational instability behavior due to the energy exchange between thermal and mechanical modes has been found to occur under certain initial conditions; the velocities range has been determined for which collective sliding instability may occur whereas the stick-slips would be not possible. The nonlinear analysis of instability evolution has been carried out for pairs with the negative thermal-frictional sliding characteristics, the final stage of sliding dynamics has been described. It is found that stable thermofrictional oscillations can occur on the nonlinear stage of sliding instability development; the oscillations frequency and amplitude have been determined. The possibility has been discussed of the experimental observation of new dynamical sliding phenomena at low temperatures.

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Numerical Simulation Analysis on the Supporting Effect of Different Pre-reinforcement Methods in Portal Section of the Shallow Buried Soft Rock Tunnel

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/455/1/012175 ◽

2020 ◽

Vol 455 ◽

pp. 012175

Author(s):

Shaohua Shi

Keyword(s):

Numerical Simulation ◽

Simulation Analysis ◽

Soft Rock ◽

Supporting Effect ◽

Rock Tunnel

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Study of An Innovative Approach of Roof Presplitting for Gob-Side Entry Retaining in Longwall Coal Mining

Energies ◽

10.3390/en12173316 ◽

2019 ◽

Vol 12 (17) ◽

pp. 3316 ◽

Cited By ~ 3

Author(s):

Xingyu Zhang ◽

Liang Chen ◽

Yubing Gao ◽

Jinzhu Hu ◽

Jun Yang ◽

...

Keyword(s):

Longwall Mining ◽

Design Method ◽

Innovative Approach ◽

Pressure Relief ◽

Working Face ◽

Longwall Coal Mining ◽

Safety Production ◽

Supporting Effect ◽

Mining Pressure

Gob-side entry retaining (GER) is a hot issue with regard to saving resources and reducing the drivage ratio in longwall mining. This paper investigates an innovative approach of roof presplitting for gob-side entry retaining (RPGER). RPGER uses the directional cumulative blasting to split the roof in advance. The rock roof within the presplitting range caves in gob after mining. The caved gangue can become the natural rib of the gob-side entry and expands to be the natural supporting body for resisting the upper roof movement. A numerical model of RPGER was established by the discrete element method (DEM), which showed that the supporting effect by the expanded gangue was well functioning. The gob-side entry was in pressure-relief surroundings and featured in the lesser deformation. The roof presplitting design method was presented and validated with a field test. The test illustrated that RPGER reduced the mining pressure on the retained entry side. The expanded gangue on the entry side was gradually compacted. It is the compaction process that played the role of reliving mining pressure, and the compacted gangue became the effective rib of the gob-side entry. The retained entry in the pressure-relief surroundings would stabilize a lagging distance behind the working face. The gob-side entry after stabilization met the entry retaining and the safety production requirements. This work illustrates the mechanism of RPGER and validates its feasibility and efficiency.

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