scholarly journals An Intelligent Temporary While-Boring Support Technology For Raise Boring Method

2021 ◽  
Vol 233 ◽  
pp. 01075
Author(s):  
Shou-ye CHENG ◽  
Feng GAO ◽  
Guo-ye JING ◽  
Ming ZHOU ◽  
Bo HAN ◽  
...  
Keyword(s):  
Economic Benefits ◽  
Industrial Test ◽  
Surrounding Rock ◽  
Test Results ◽  
Rock Support ◽  
Test Study ◽  
Rock Formations ◽  
Supporting Material ◽  
The Stability ◽  
The Impact

Ensuring the stability of the shaft structure is one of the key technologies for the application of raise boring method. In the process of reaming through rock formations with water disintegration characteristics, the impact of water gushing and drenching may induce partial collapse. To solve this problem, an intelligent temporary while-boring support technology is proposed in this paper. Firstly, the main characteristics of the technology are introduced. Utilizing the space inside the raise boring pipes, the material conveying pipes and nozzle can reach the lower part of the reamer to realize spraying support. Secondly, a composite cementitious supporting material with good mechanical properties is developed to ensure the sealing and waterproofing of the surrounding rock. Thirdly, a test study was carried out on key process parameters. The results show that the best engineering economic benefits under the condition that the rotation speed is 2r/min and the distance between the nozzle and the surrounding rock is 1m. Fourthly, an image classification algorithm based on Resnet-34 convolutional neural network is proposed, which realizes the intelligent judgment of the effect of surrounding rock support. Finally, an industrial test was carried out in Lijiahao Coal Mine. The test results show that the intelligent temporary while-boring support technology proposed in this paper has a good performance, effectively achieving the sealing and water resistance of the surrounding rock, and the shaft structure has not been damaged.

Model estimates of the results of diabetes patients using modern glucometers with tri-color technology for displaying test results

2019 ◽  
pp. 81-89
Author(s):  
Larisa Dmitrievna Popovich ◽  
Svetlana Valentinovna Svetlichnaya ◽  
Aleksandr Alekseevich Moiseev
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 1 Diabetes ◽  
Economic Benefits ◽  
Test Results ◽  
Self Monitoring ◽  
Patients With Diabetes ◽  
The Impact

Diabetes – a disease in which the effect of the treatment substantially depends on the patient. Known a study showed that the use of glucometers with the technology of three-color display of test results facilitates self-monitoring of blood sugar and leads to a decrease in glycated hemoglobin (HbAlc). Purpose of the study: to modeling the impact of using of a glucometer with a color-coded display on the clinical outcomes of diabetes mellitus and calculating, the potential economic benefits of reducing the hospitalization rate of patients with diabetes. Material and methods. Based on data from two studies (O. Schnell et al. and M. Baxter et al.) simulation of the reduction in the number of complications with the use of a glucometer with a color indication. In a study by O. Schnell et al. a decrease of HbA1c by 0.69 percent is shown when using the considered type of glucometers, which was the basis of the model. Results. In the model, the use of a glucometer with a color-coded display for type 1 diabetes led to a decrease in the total number of complications by 9.2 thousand over 5 years per a cohort of 40 thousand patients with different initial levels of HbA1c. In a cohort of 40 thousand patients with type 2 diabetes, the simulated number of prevented complications was 1.7 thousand over 5 years. When extrapolating these data to all patients with diabetes included in the federal register of diabetes mellitus (FRD), the number of prevented complications was 55.4 thousand cases for type 1 diabetes and 67.1 thousand cases for type 2 diabetes. The possible economic effect from the use of the device by all patients with a diagnosis of diabetes, which are included in the FRD, estimated at 1.5 billion rubles for a cohort of patients with type 1 diabetes and 5.3 billion rubles for patients with type 2 diabetes. Conclusion. Improving the effectiveness of self-monitoring, which is the result of the use of glucometers with color indicators, can potentially significantly reduce the incidence of complications in diabetes and thereby provide significant economic benefits to society.

scholarly journals Failure behavior of the surrounding rock of jointed rock masses in a gold mine under impact disturbance

2021 ◽  
Author(s):  
Peng Li ◽  
Yunquan Wu ◽  
Meifeng Cai
Keyword(s):  
Stress Wave ◽  
Shear Failure ◽  
Jointed Rock ◽  
Surrounding Rock ◽  
Tensile Failure ◽  
Tensile Shear ◽  
Underground Engineering ◽  
Impact Stress ◽  
The Stability ◽  
The Impact

Abstract The impact disturbance has an important influence on the safety of underground engineering openings. In this paper, based on the in-situ stress measurement and structural plane investigation, the model of jointed rock roadway was established using the discrete element method (3DEC) to study the instability and failure characteristic of roadway surrounding rock with dominant joint planes under impact disturbance and to further analyze the influence of different buried depths, impact stress wave peaks, and stress wave delays on the stability of the surrounding rock. The results show that the stability of the surrounding rock is poor, and the whole convergence deformation of the surrounding rock occurs under the impact stress wave. There are three failure modes in the surrounding rock: tensile-shear failure, tensile failure, and shear failure. Tensile-shear failure mainly occurs in a small range close to the roof and floor of the roadway and the free surfaces of the two sides, and tensile failure occurs locally, while shear failure mainly occurs along the joint plane outside this range. Moreover, the greater the buried depth and stress wave peak value, the more serious the deformation of the surrounding rock. With the increase of stress wave delay, the deformation of the surrounding rock shows complex characteristics. In addition, the impact failure mechanism of the surrounding rock in jointed rock masses was discussed. The research results have important guiding significance for the prevention and control of underground engineering cavern disasters.

scholarly journals EFFECT OF BLASTING ON THE STABILITY OF LINING DURING EXCAVATION OF NEW TUNNEL NEAR THE EXISTING TUNNEL

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Quang Huy Nguyen
Keyword(s):  
Field Data ◽  
Damage Zone ◽  
Field Tests ◽  
Surrounding Rock ◽  
In Situ Test ◽  
The Stability ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working.

Experimental Analysis on Microstructure and Mineral Composition of Jurassic Soft Rock in Shajihai Mining Area of Xinjiang

2013 ◽  
Vol 353-356 ◽  
pp. 24-27
Author(s):  
Xiao Lei Wang ◽  
Shun Xi Yan ◽  
Hai Qiao Wen
Keyword(s):  
Mineral Composition ◽  
Soft Rock ◽  
Mining Area ◽  
Sem Analysis ◽  
Surrounding Rock ◽  
Test Results ◽  
X Ray Diffraction ◽  
Component Content ◽  
The Stability ◽  
Soft Rock Roadway

In order to find out themicroscopic structure and determine mineral composition and relative content ofroadway soft rock in Shajihai mining area, this paper carried out experimentsof scanning electron microscope (SEM) analysis and X-ray diffraction analysis.SEM test results show that the microstructure of the surrounding rock isgenerally poor and joint, crack, pore are developed. The crack is easy toexpand under the effect of surrounding rock pressure and water, which makesrock mass more broken and greatly reduces the stability of surrounding rock.X-ray diffraction analysis test shows that the component content of clayminerals in the surrounding rock is high. Clay mineral in mudstone containsmontmorillonite and content of illite/smectite mixed layer is relativelyhigher, up to 45%. In conclusion, soft rock roadway of Shajihai mine areabelongs to the typical swelling-jointed compound soft rock. The targeted andreasonable compound transformation technology and coupling support measuresmust be adopted when supporting.

scholarly journals The effects of gravel cushion particle size and thickness on the coefficient of restitution in rockfall impacts

2018 ◽  
Vol 18 (6) ◽  
pp. 1811-1823 ◽  
Author(s):  
Chun Zhu ◽  
Dongsheng Wang ◽  
Xing Xia ◽  
Zhigang Tao ◽  
Manchao He ◽  
...  
Keyword(s):  
Particle Size ◽  
Impact Energy ◽  
Coefficient Of Restitution ◽  
Open Pit ◽  
Test Results ◽  
Drop Tests ◽  
Damage Depth ◽  
The Stability ◽  
Energy Absorbing ◽  
The Impact

Abstract. Gravel cushions are widely used to absorb the impact energy of falling rocks in open-pit mines. A particularly important application is to enhance the energy-absorbing capacity of rockfall sheds. In this paper, we study how varying the thickness and particle size of a gravel cushion influences its energy-consumption and buffering effects. We performed a series of laboratory drop tests by dropping blocks from a fixed height onto cushions of different thicknesses and particle sizes. The results indicate that, for a given impact energy, the cushion thickness has a strong influence on the measured coefficient of restitution (COR) and therefore impact pressure. Additional tests were performed to study how the radius of the block and the height it is dropped from affect the measured COR. This showed that as the movement height of the block is increased the COR also increases, and blocks with larger radii exhibit a larger variability in measured COR. Finally, we investigated the influence of rockfall block radius, r, movement height, H, cushion thickness, h, and particle size, d, on the COR and the damage depth, L, of the cushion. The test results reveal that the cushion thickness is the primary design parameter, controlling not only COR, but also the stability of the cushion material. The results provide a theoretical and practical basis for the design of gravel cushions for rockfall protection.

Study of the Trellis Support of Working Face Roadway in Impact Coal Seam

2014 ◽  
Vol 941-944 ◽  
pp. 2558-2564
Author(s):  
Yu Kai Lv ◽  
Cong Jiang ◽  
Yao Dong Jiang
Keyword(s):  
In Situ Stress ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Working Face ◽  
Coal Bumps ◽  
Roadway Support ◽  
The Stability ◽  
The Impact ◽  
Physical And Mechanical Characteristics

Coal bumps happened many times in mining at No.5 seam of Tangshan coal mine. Strengthen the roadway’s support of working face can effectively reduce disaster losses. With the research background of the 3654 working face, the mine pressure monitoring for the existing support form of roadway has been carried on. Perform a numerical simulation for the original roadway support, base on the in-situ stress and physical and mechanical characteristics of surrounding rock in experimental; study the impact of the stability of roadway’s surrounding rock, while the space change of trellis and change of supporting intensity; optimizing the original support form, so as to maximum reducing the impact of the coal bumps.

A New Criterion for Stability Analysis of Tunnel Surrounding Rock-Support Structure Based on the Convergence-Confinement Method

2012 ◽  
Vol 629 ◽  
pp. 427-432
Author(s):  
Yong Kang ◽  
Bo Long Chai ◽  
Xiao Chuan Wang ◽  
Deng Li
Keyword(s):  
Stability Analysis ◽  
Surrounding Rock ◽  
Geological Condition ◽  
Rock Support ◽  
Support Structure ◽  
Weak Zone ◽  
Deformation And Failure ◽  
True Value ◽  
The Stability ◽  
Ultimate Displacement

In the decision making of tunnel excavation and support scheme, stability analysis of surrounding rock-support structure is an essential link. Especially in fractured weak zone under complex geological condition, accurately measuring the deformation of support structure has an important significance for fast and safe construction. Based on the application of convergence confinement principle in judging tunnel deformation, this paper presented a new idea of using the ultimate displacement of tunnel initial support to analyze the stability of tunnel surrounding rock-support structure. Then, with a full investigation on the deformation and failure characteristics of highway tunnel surrounding rock at fractured weak zone, the ultimate displacement was got by using methods of numerical calculation and site monitoring measurement. Finally, the stability analysis of support structure in Zhongxing Tunnel was done. It can be arrived that there is a certain gap between true value u and measured value um of surrounding rock deformation. If the measuring points are installed after three excavation cycle, u is approximately equal to 1.6 um. then, based on the analysis of numerical simulation results and monitoring data of Zhongxing Tunnel, the paper indicated that the top and spring of arch are risk regions, reserved deformation of fractured weak zone is not enough, it should be adjusted from 10cm to 20cm.

Anchorage Effect on Fractured Rock and Cavern Stability

2011 ◽  
Vol 90-93 ◽  
pp. 618-621
Author(s):  
Wen Wang ◽  
Wei Shen Zhu ◽  
Min Yong
Keyword(s):  
Fractured Rock ◽  
Surrounding Rock ◽  
Test Results ◽  
Propagation Process ◽  
Laboratory Test Results ◽  
Key Points ◽  
Splitting Test ◽  
Crack Propagation Process ◽  
The Stability ◽  
Rock Specimens

The effect of anchor on fractured rock specimens in splitting test is simulated by DDARF method in this research. The results are compared and agree well with laboratory test results. The DDARF program is also adopted to analyze the stability of an underground cavern with four groups of randomly generated joints in the surrounding rocks, in which two conditions with and without rock bolts are considered. Besides, the crack propagation process around the cavern and the displacements of key points in the surrounding rock are monitored and applied to investigate the stability of the cavern.

Impact monitoring characteristics of piezoelectric paint sensor by thermal fatigue analysis for railroad vehicle applications

2020 ◽  
Vol 19 (6) ◽  
pp. 1951-1962
Author(s):  
Kyungwho Choi ◽  
Mun-Young Hwang ◽  
Donghoon Kang ◽  
Myeongcheol Kang ◽  
Dahoon Ahn ◽  
...  
Keyword(s):  
Thermal Fatigue ◽  
Aerodynamic Drag ◽  
Test Results ◽  
Railroad Vehicles ◽  
Additional Layer ◽  
Impact Monitoring ◽  
Nano Powder ◽  
The Stability ◽  
The Impact ◽  
Railroad Vehicle

The strong aerodynamic drag under a railroad vehicle in motion causes the track ballast to fly up and around. The flying ballast can collide with the underside of the coach, damaging the electronics installed there. There are even cases wherein the aerodynamics of fast-moving train causes the gravel to hit the side of the coach and break the windows. Extensive and numerous studies are underway to reduce the damage caused by such phenomena. In this study, a “smart paint sensor” for impact monitoring was fabricated using piezoelectric nano powder and commercial paint for railroad vehicles, and the application of impact monitoring to railroad vehicles was analyzed. The process was simplified because the use of commercial paint eliminated the need to apply an additional layer of functionalized paint. Furthermore, the fact that the paint can be evenly sprayed on a large surface made it suitable for use on large and intricate objects such as a railroad vehicle bogie. Because railroad vehicles are exposed to thermal stress for a long period of time, a thermal fatigue test was conducted in order to figure out the stability of the polymer-based material, which is relatively vulnerable to temperature variations. The test results were used to analyze the impact sensitivity of the piezoelectric paint sensor. For the analysis, a full-size mock-up of the railroad vehicle bogie and an impact monitoring system with piezoelectric paint sensor were implemented in order to visualize the impact signals from differently shaped objects with large surfaces.

scholarly journals Study on Mechanical Characteristics of Energy-Absorbing and Anti-Scour Bolts

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhi Tang ◽  
Hao Wu ◽  
Jinguo Lv ◽  
Zhuangzhuang Xin ◽  
Wenbo Zuo
Keyword(s):  
Impact Energy ◽  
Mechanical Performance ◽  
Impact Resistance ◽  
Energy Criterion ◽  
Energy Balance Equation ◽  
Surrounding Rock ◽  
Support Design ◽  
The Stability ◽  
Energy Absorbing ◽  
The Impact

In order to improve the impact resistance and mechanical performance of anchor rods and satisfy the requirements for supporting rockburst roadways, the energy balance equation of the energy-absorbing support and roadway surrounding rock system is established. Moreover, to effectively prevent rockburst disasters, the energy criterion for roadway instability is derived. From the perspective of an energy-absorbing support, a yield-absorbing anti-shock anchor composed of a rod body, tray, constant resistance energy-absorbing device, and special-shaped nut is designed and developed; compared with ordinary anchor rods, this rod has stronger mechanical properties for resisting impact. Theoretical and numerical simulation studies show that the energy-absorbing device has a repeatable deformation failure mode and a constant yield force. The paper also presents the principle involved in the design of anti-shock bolt supports. The energy-absorbing support not only effectively guides and controls the release and conversion of impact energy but also consumes the impact energy in the buffering process of the anchor to ensure the stability of surrounding rock and support protection system. This study aims to provide reference for roadway support design and to improve rock bolts used in rockburst roadways.

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