A new perspective for support design of shallow tunnels in mudstone formation: basic philosophy and engineering practice

Aiming at the problem of large-scale deformation of the track and alleys in the East Second Mining Area, the numerical analysis method is used to analyze the stress and deformation law of the roadway. The results show that the critical depth of the roadway deformation is 800m, the shear stress of the deep roadway is about 8.7MPa in the left and right shoulders, and the vertical stress increases sharply in the range of 0~5.5m from the center of the roadway, and is 6~ from the center of the roadway. The peak value is reached within 8m, the plastic zone of the roadway roof is 2.6m, the left and right plastic zones are 5.2m and 5.4m, respectively, and the plastic zone of the floor is 6.1m. This result can provide a basis for the design parameters of deep soft rock roadway support. The engineering practice proves that the support design effectively controls the strong deformation of the roadway and achieves better support effect.

Download Full-text

Study on Column-Top Seismic Isolation of Single-Layer Latticed Domes

Sustainability ◽

10.3390/su11030936 ◽

2019 ◽

Vol 11 (3) ◽

pp. 936 ◽

Cited By ~ 2

Author(s):

Yongmei Zhai ◽

Xuxia Fu ◽

Yihui Chen ◽

Wei Hu

Keyword(s):

Seismic Isolation ◽

Time History ◽

Single Layer ◽

Nonlinear Time History Analysis ◽

Hysteresis Curve ◽

Plastic State ◽

Original Structure ◽

Engineering Practice ◽

Support Design ◽

Support Reaction

In this paper, a single-layer lamella reticulated dome with reinforced concrete bearings was studied, and a method of column-top isolation was proposed to improve the seismic performance of the whole structure, thereby avoiding too large support stiffness in engineering practice. A nonlinear time-history analysis showed that lead rubber bearings (LRB) can reduce the support reaction to a certain extent and make it distribute uniformly, reducing the support design requirements under frequent earthquakes. During rare earthquakes, the LRB was basically in the plastic state and the support reaction remained near the yield force, which was reduced greatly compared with that of the original structure. The bearing hysteresis curve was full, while the plasticity development degree of the upper reticulated dome was greatly reduced and the elasticity was basically maintained, thus achieving a good damping effect.

Download Full-text

An Improved BP Neural Network Algorithm for Prediction of Roadway Support

International Journal of Circuits, Systems and Signal Processing ◽

10.46300/9106.2021.15.43 ◽

2021 ◽

Vol 15 ◽

pp. 393-399

Author(s):

Yan-Jun He ◽

Jin-shan Zhang ◽

Chao-Gang Pan

Keyword(s):

Neural Network ◽

Bp Neural Network ◽

Engineering Practice ◽

Related Factors ◽

Support Design ◽

Network Training ◽

Coal Roadway ◽

Allowable Range ◽

Roadway Support ◽

New Research

Based on the engineering practice and the research and analysis of the knowledge in the field of roadway support, the paper puts forward to use an improved BP neural network to study the supporting types by the investigation, and obtained the related factors of the supporting types of the mining roadway and the successful reinforcement cases of the roadway. The proposed algorithm is applied to the prediction of coal roadway support parameters, and the main influencing factors of coal roadway support design are determined. From the typical engineering cases of roadway support collected on site as neural network training samples, the forecasting model of support parameters is established. Through the experimental data and simulation results, it can be seen that both the error convergence process and results of convergence speed, convergence accuracy and support types are ideal, the prediction error is within the allowable range, and the prediction accuracy is high, which verifies the reliability of this method and provides a new research idea and good application value for the study of support types of mining roadway.

Download Full-text

Experimental analysis of control technology and deformation failure mechanism of inclined coal seam roadway using non-contact DIC technique

Scientific Reports ◽

10.1038/s41598-021-00462-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Xianyu Xiong ◽

Jun Dai ◽

Yibo Ouyang ◽

Pan Shen

Keyword(s):

Coal Seam ◽

Failure Mechanism ◽

Stability Control ◽

Surrounding Rock ◽

Image Correlation ◽

Engineering Practice ◽

Control Technology ◽

Support Design ◽

Deformation Control ◽

Geological Conditions

AbstractThe deformation and failure forms of inclined coal seam roadway under the joint action of dip angle and various geological conditions are complex, and there is a lack of targeted support measures, which brings great problems to the stability control of roadway surrounding rock. In order to safely and economically mine inclined coal seams, taking the engineering geology of Shitanjing No. 2 mining area as the background, and the physical similarity model of right-angle trapezoidal roadway in inclined coal seam, in which the non-contact digital image correlation (DIC) technology and the stress sensor is employed to provide full-field displacement and stress measurements. The deformation control technology of the roadway surrounding rock was proposed, verified by numerical simulation and applied to engineering practice. The research results show that the stress and deformation failure of surrounding rock in low sidewall of roadway are greater than those in high sidewall, showing asymmetric characteristics, and the maximum stress concentration coefficients of roadway sidewall, roof and floor are 4.1, 3.4 and 2.8, respectively. A concept of roadway "cyclic failure" mechanism is proposed that is, the cyclic interaction of the two sidewalls, the sharp angles and roof aggravated the failure of roadway, resulting in the overall instability of roadway. The roadway sidewall is serious rib spalling, the roof is asymmetric "Beret" type caving arch failure, and the floor is slightly bulging. On this basis, the principle of roadway deformation control is revealed and asymmetric support design is adopted, and the deformation of roadway is controlled, which support scheme is effective.

Download Full-text

REALIZING CEAB GRADUATE ATTRIBUTES USING THE CASE METHOD

Proceedings of the Canadian Engineering Education Association (CEEA) ◽

10.24908/pceea.v0i0.4655 ◽

2012 ◽

Author(s):

David Effa ◽

Steve Lambert ◽

Oscar Nespoli

Keyword(s):

Engineering Design ◽

Learning Outcomes ◽

Case Studies ◽

Work Experience ◽

Primary Objective ◽

Engineering Problem ◽

Engineering Practice ◽

Graduate Attributes ◽

New Perspective ◽

Undergraduate Programs

The University of Waterloo (UW) offers seven fully accredited and internationally competitive engineering undergraduate programs. It has the largest undergraduate co-operative education program in the world, and the largest Engineering program in Canada. All UW engineering departments are refining and evaluating their undergraduate curricula in order to address the new Canadian Engineering Accreditation Board (CEAB) requirements, with its focus on learning outcomes and graduate attributes. This new perspective provides an opportunity for alternative pedagogical approaches for developing and assessing graduate attributes. Over the past several years, the Waterloo Cases in Design Engineering (WCDE) group at UW has been developing and promoting the use of engineering design cases throughout the curriculum. These cases are developed primarily from our own students’ work term experience. Cases provide an effective pedagogical method to integrate students’ technical knowledge as well as develop appropriate engineering skills. Engineering cases help students understand and better appreciate the complexity of engineering practice, and gain valuable experience in engineering problem solving and working in teams. They naturally complement the real-world work experience they get on their co-op terms. The primary objective of this paper is to present the use of case studies to promote active learning and assessment of engineering design with a focus on the CEAB graduate attributes. Some case studies have been developed to focus on specific CEAB attributes. An example case study will be presented, its implementation discussed, and the effectiveness of achieving the targeted learning outcomes will be discussed.

Download Full-text

Experimental Analysis and Control Technology of Deformation and Failure Mechanism of Inclined Coal Seam Roadway using Non-contact DIC Technique: A Case Study

10.21203/rs.3.rs-754129/v1 ◽

2021 ◽

Author(s):

xianyu xiong ◽

Jun Dai ◽

Yibo Ouyang ◽

Pan Shen

Keyword(s):

Coal Seam ◽

Failure Mechanism ◽

Surrounding Rock ◽

Image Correlation ◽

Engineering Practice ◽

Control Technology ◽

Support Design ◽

Deformation And Failure ◽

Full Field ◽

Deformation Control

Abstract In order to study the deformation and failure mechanism of surrounding rock of roadway in inclined coal seam, the physical similarity model of right-angle trapezoidal roadway in inclined coal seam, in which the non-contact digital image correlation (DIC) technology and the stress sensor is employed to provide full-field displacement and stress measurements. The deformation control technology of the roadway surrounding rock was proposed and applied to engineering practice. The research results show that the stress and deformation failure of surrounding rock in low sidewall of roadway are greater than those in high sidewall, showing asymmetric characteristics, and the maximum stress concentration coefficients of roadway sidewall, roof and floor are 4.1, 3.4 and 2.8, respectively. A concept of roadway "cyclic failure" mechanism is proposed that is, the cyclic interaction of the two sidewalls, the sharp angles and roof aggravated the failure of roadway, resulting in the overall instability of roadway. The roadway sidewall is serious rib spalling, the roof is asymmetric "Beret" type caving arch failure, and the floor is slightly bulging. On this basis, the principle of roadway deformation control is revealed and asymmetric support design is adopted, and the deformation of roadway is controlled, which support scheme is effective.

Download Full-text

SREM observation of the interaction between the in-situ deposited Pd small particles and MgO cleavage surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143523 ◽

1986 ◽

Vol 44 ◽

pp. 382-383

Author(s):

H.-J. Ou

Keyword(s):

Electron Microscopy ◽

Small Particle ◽

Small Particles ◽

Cleavage Surface ◽

Metallic Particles ◽

Microscopy Technique ◽

Ceramic Surfaces ◽

Reflection Electron Microscopy ◽

New Perspective

The understanding of the interactions between the small metallic particles and ceramic surfaces has been studied by many catalyst scientists. We had developed Scanning Reflection Electron Microscopy technique to study surface structure of MgO hulk cleaved surface and the interaction with the small particle of metals. Resolutions of 10Å has shown the periodic array of surface atomic steps on MgO. The SREM observation of the interaction between the metallic particles and the surface may provide a new perspective on such processes.

Download Full-text

Articulation Training: A New Perspective

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.1003.145 ◽

1979 ◽

Vol 10 (3) ◽

pp. 145-151 ◽

Cited By ~ 1

Author(s):

Sallie W. Hillard ◽

Laura P. Goepfert

Keyword(s):

Life Experience ◽

Remediation Measures ◽

New Perspective

This paper describes the concept of teaching articulation through words which have inherent meaning to a child’s life experience, such as a semantically potent word approach. The approach was used with six children. Comparison of pre/post remediation measures indicated that it has promise as a technique for facilitating increased correct phoneme production.

Download Full-text