scholarly journals Application of FRP Bolts in Monitoring the Internal Force of the Rocks Surrounding a Mine-Shield Tunnel

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2763 ◽  
Author(s):  
Zhen Liu ◽  
Cuiying Zhou ◽  
Yiqi Lu ◽  
Xu Yang ◽  
Yanhao Liang ◽  
...  

Monitoring the internal force of the rocks surrounding a mine-shield tunnel for the initial support of a mine-shield tunnel, in complex geological and hydrological environments, requires bolts with specific features such as high tensile strength, low shear strength, good insulation and resistance to corrosion. As such, internal force monitoring has become an important issue in safety monitoring for such tunneling projects. In this paper, the adaptability of a mine-shield tunnel project in a corrosive environment is investigated. A fiberglass reinforced plastic (FRP) bolt with high tensile strength, low shear strength, resistance to fatigue, non-conductivity and resistance to corrosion is used as a probe in tandem with an anchor-head dynamometer to monitor the internal force of the rocks surrounding a mine-shield tunnel for initial support. Additionally, solar energy collection technology is introduced to create a remote monitoring system. Using a 2.5 km long railway tunnel located in the northeast of the Pearl River Delta of China as a case study, the present study shows that, compared with a conventional steel bolt, the FRP bolt has advantages, such as avoidance of the risks associated with the shield machine, insulation and resistance to corrosion. As a probe, the response of the FRP bolt to events such as a blasting vibration and a construction disturbance that results in internal changes in the surrounding rock demonstrates a clear pattern that is appropriate for monitoring the internal force of the rocks surrounding a mine-shield tunnel in a corrosive environment. FRP bolt-based monitoring not only provides new technological support for controlling the risk involved in the initial support of a mine-shield tunnel but can also be widely deployed in projects with special requirements for disassembly, conductivity and corrosion.

2013 ◽  
Vol 846-847 ◽  
pp. 40-43
Author(s):  
Jian Feng Qin ◽  
Xiu Ming Jiang ◽  
Jian Cheng Yang ◽  
Hua Qing Wang ◽  
Kai Yang ◽  
...  

This paper presents a new constant tension control device which is suitable for warping of the carbon fiber or the flake yarns which are zero twist, high tensile strength, low shear strength, high specific modulus and self-lubrication and can meet the requirements of the warp tension of the carbon fiber multi-layer weaving equipment which is in the process of development. The device can make yarn tension consistent in warping process. Especially with the decrease of the diameter of yarn tube, the tension of yarn sheet is consistent in warping process. In the process of warping the warp doesnt twist and wear is small. The experimental results show that the mechanism can realize accurate control on the tension of the single yarn and the yarn sheet, and is able to meet the requirements of the warp tension of the carbon fiber multi-layer weaving equipment which is in the process of development.


Alloy Digest ◽  
1997 ◽  
Vol 46 (12) ◽  

Abstract Vasco 9-4-30 (0.30 wt% C) is a premium quality aircraft steel which combines high tensile strength with good fracture toughness. It is a heat treatable alloy capable of developing ultimate tensile strengths greater than 250 ksi. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: SA-491. Producer or source: Vasco, An Allegheny Teledyne Company.


2014 ◽  
Vol 802 ◽  
pp. 311-316 ◽  
Author(s):  
Gisele Hammes ◽  
Priscila da Costa Gonçalves ◽  
Cristiano Binder ◽  
Kaline Pagnan Furlan ◽  
Aloisio Nelmo Klein

In order to develop a composite for future applications as self-lubricating material, samples with iron matrix and contents of hexagonal boron nitride (hBN) of 0, 2.5, 5, 7.5 and 10 vol%. were produced by conventional powder metallurgy, varying the compacting pressures. It was observed a decrease of mixture flowability and apparent density when increasing hBN content. Moreover, the samples showed an increment of green densification with the increase of applied pressures and hBN contents, suggesting that hBN particles accommodate into the voids during pressing. As known, hBN has low shear strength and is insoluble in the iron matrix, which hinder the formation of necks between the particles of iron during sintering. To improve matrix continuity the double pressing technique was used, and this technique presented increments of 3 to 5% of densification and up to 95% of tensile strength when compared with the composites produced by single pressing.


Alloy Digest ◽  
1959 ◽  
Vol 8 (1) ◽  

Abstract MEEHANITE type GM is a high strength iron which may be cast uniformly solid regardless of casting size or sectional deviation. This particular engineering material possesses true elastic properties, conferring both controlled stiffness and resilience which provides good impact strength and shock resistance in combination with high tensile strength and assured solidity. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness and fatigue. It also includes information on heat treating and machining. Filing Code: CI-25. Producer or source: Meehanite Metal Corporation.


Alloy Digest ◽  
1965 ◽  
Vol 14 (4) ◽  

Abstract HY-TUF is a low alloy, tough, through-hardening, high tensile strength steel. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness, deformation, and fatigue. It also includes information on low temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-30. Producer or source: Crucible Steel Company of America. Originally published May 1955, revised April 1965.


Alloy Digest ◽  
1981 ◽  
Vol 30 (8) ◽  

Abstract CENTRI-CAST GRAY IRON 50 is a centrifugally cast gray iron with a nominal tensile strength of 50,000 psi. It is cast in the form of tubing which has a wide range of uses in applications where size and shape are of paramount importance and freedom from pattern cost is an important consideration. Among its many applications are farm machinery, seals, bushings, machine tools and general machinery uses. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-51. Producer or source: Federal Bronze Products Inc..


Alloy Digest ◽  
1979 ◽  
Vol 28 (9) ◽  

Abstract CENTRI-CAST GRAY IRON 55 is a centrifugally cast gray iron with a nominal tensile strength of 55,000 psi. It is produced in the form of tubing which has a wide range of uses in applications where size and shape are of paramount importance and freedom from pattern cost is an important consideration. Typical applications are seals, bushings, farm machinery, casings and general machinery uses. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-48. Producer or source: Federal Bronze Products Inc..


Alloy Digest ◽  
2020 ◽  
Vol 69 (9) ◽  

Abstract Lucefin Group C30, C30E, and C30R are medium-carbon, non-alloy steels that are used in the normalized, cold worked, or quenched and tempered condition. C30E and C30R may also be flame or induction hardened. C30, C30E, and C30R are widely used for small, moderately stressed parts, where higher strength levels are needed than can be achieved in the lower carbon grades, and also where toughness is more important than high tensile strength. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: CS-206. Producer or source: Lucefin S.p.A.


Alloy Digest ◽  
1997 ◽  
Vol 46 (10) ◽  

Abstract Vasco 9-4-20 (0.20 wt% C) is a premium quality aircraft steel that combines high tensile strength with good fracture toughness. It is a heat-treatable alloy capable of developing an ultimate tensile strength greater than 190 ksi. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: SA-489. Producer or source: Vasco, An Allegheny Teledyne Company.


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