bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surrounding rock deformation and supporting measures on small structure in non-pillar mining with gob-side entry retaining
Authors: Yang Jun , Qiao Bowen , Gao Yubing , Zhang Jiabin , Wei Xingjian , Fu Qiang 
Published: November 2020

Abstract
This study proposes a “large and small structure” concept of cutting cantilever based on the technical principle of gob-side entry retaining in a non-pillar. A mechanical structure model of the “small structure” concept of cutting cantilever is established by analyzing the stress transfer mechanism of the overlying strata in the gob-side entry. The calculation formula of the roof sinking is derived. The deformation law of the surrounding rock and the roof subsidence characteristics in the small structure are studied using a numerical analysis method. Moreover, the surface displacement curve is obtained by combination with the field measurement. The results show that the cutting structural plane generated by pre-splitting blasting effectively changes the stress transfer between the roof of the gob-side entry and the working face, which is beneficial to the rapid formation of the large structure with a self-stabilization bearing. The deformation of the surrounding rock of a “small structure” roadway is significantly controlled and combined with the rigid support system comprising constant-resistance and large-deformation anchor cables, gangue prevention structures, and a pier-beam unit. The gangues in the goaf interact with the large and small structures formed by the surrounding rock of the gob-side entry retaining, thereby forming a synergistic support structure for effectively increasing roadway stability.
Improvement and application of drilling and blasting techniques of anchor net (cable) spraying in rock roadways
Authors: Wen Zhongyi 
Published: November 2020

Abstract
To overcome the shortcomings of the prior art of bolting net (cable) spraying technology in rock tunnels of mine engineering, based on the principle of the combined action of surrounding rock and support, improvement methods and technical requirements are formulated. Through roadway section optimization and support parameter design and improvement of technology, smooth blasting, initial shotcreting, and construction quality of the anchor net (cable) as well as controlled release of the surrounding rock stress and local reinforcement are improved, so that the surrounding rock and support can be carried out together. Finally, through thin shotcreting, the coupling effects of the anchor net (cable), shotcreting layer, and surrounding rock can be realized, and the bearing performance can be brought into play to achieve the best support effect and ensure that the net section meets the requirements with minimal investment. The test shows that the improved technology can effectively solve problems of large area cracking and convergence deformation; the effect is positive and highly recognized by the industry, and it has been popularized and applied in this area and brother units. Large economic and social benefits have also been obtained.
Presplitting cutting slots technique of roof cutting entry retaining and its impact on strata behavior law of workface in Baoshan coal mine
Authors: Jun YANG , Cheng Yu , Xingen MA , Zhang Jiabin , Kuikui Chen , Rundong Zhao 
Published: November 2020

Abstract
Presplitting cutting slots advance working face is the key technology of non—pillar gob—side entry retaining formed by roof cutting and pressure release. And the rationality of parameters not only affects the formation of the structural surface of joint-cutting, but also has a significant impact on the retaining roadway. In order to enrich and improve the system of presplitting cutting slots technology, this paper takes the 6302 working face in Baoshan Coal Mine as the research object to discuss the effect of presplitting cutting slots technology on the strata behavior law of the working face. Then the presplitting cutting height, cutting angle and the distance between blasting holes are determined as the key parameters based on theoretical calculation. And the working face hydraulic support monitoring data are analyzed statistically. The research shows that: when the cutting height, cutting angle and the distance between blasting holes is 5m, 15 °and 500 mm respectively, the structural surface of joint-cutting can form through cumulative blasting. The influence range of pre-splitting roof joint-cutting technology on underground pressure is 30m. Furthermore, the average holding power of the powered support decreased by 3.8mpa, and the first weighting interval and periodic weighting length of the roof respectively increased by 4m and 5.5m in the affected area.
Research on the Mining Effect of Floor Strata in Deep Coal Seam Mining: A Case Study of #7 Coal Seam at Chazhuang Coal Mine
Authors: Zhang Wenquan , Wu Xintao , Shao Jianli , Ren Yanghui , Wang Zaiyong 
Published: November 2020

Abstract
Studying the mining effect of floor strata in deep coal seam mining is beneficial for evaluating and relieving the risk of water inrush from the floor. In addition, such research forms the basis for ensuring the support and stability of roadways and chambers in the lower part of the coal seam. By considering the mining of #7 coal seam in the 7600 deep mining area of the Chazhuang coal mine in Feicheng coalfield as the engineering background, this study analyzes the distribution law of mining abutment pressure and the range of failure depth affected by mining using elastic theory. In addition, the stress, strain, and failure states of the floor rock mass affected by mining are comprehensively simulated and studied using the FLAC3D finite difference software combined with field measurement results of rock movement in the lower roadway of the #7 coal seam. The mining effect of the floor is further compared and studied, providing a scientific reference basis for realizing the safe mining of coal in confined water in the deep lower group of the Feicheng coalfield.
Stress-induced brittle failure of surrounding rock mass and its engineering countermeasures in the Baihetan underground powerhouse
Authors: Chen J L , Li L Q , Wan X B , Fang D , Buyue Y G 
Published: November 2020

Abstract
Stress-induced brittle failures, such as spalling, slabbing, and rockburst, are common failure modes of underground caverns in high-stress zones. In the Baihetan Hydropower Station, the brittle failures, embodied as spalling, rock fracturing, and time-dependent deformation, bring new challenges to the excavation and support system design of underground caverns. Based on the New Austrian Tunneling Method, the specific design principles for the underground caverns of Baihetan Hydropower Station are proposed, the keys of which are preconditioning surrounding rock mass, reducing the excavation damage, supporting quickly in the proper sequence, and controlling loosen zones. These principles are applied during construction, and a series of excavation and support methods are developed for the key parts of the powerhouse, such as the roof arch, the rock wall of rock-bolted crane girder, the high side wall, and the partition wall of the generator pit. Data obtained from visual appearance, displacement measurement, and acoustic testing show that the proposed design principles are appropriate and that the developed excavation and support methods can control the range and depth of stress-induced failure of the surrounding rock mass.
Interaction between soft rocks and water and its application to engineering
Authors: Zeng Qinghe , Ming Weihua , Wang Xiangdong , Liu Zhen , Tan Xiangshao , Zhou Cuiyng 
Published: November 2020

Abstract
The interaction between soft rocks and water is a frontal project in the field of geotechnical engineering. This study constructs a time-effect model on the interaction between soft rocks and water by experimenting on the interaction and physical-mechanic of soft rocks, such as silty mudstone, argillaceous siltstone, and carbonaceous mudstone, which are sampled from a water supply project in South China. It also investigates the chemical mechanism of softening when soft rocks interact with water. Thus, the study not only builds a foundation for the theme of water–rock interaction but also provides effective guidance for the construction of priority projects.
Research and microscopic analysis of seepage characteristics of sandstone under low-frequency cyclic loading
Authors: Chunde Ma , Shan Long , Xibing Li , Zelin Liu , Weibin Xie 
Published: November 2020

Abstract
The change of rock permeability properties under cyclic load is of great significance to the safety of underground engineering. However, there are few studies on triaxial seepage tests under different cyclic loads, and most of them have not carried out microscopic mechanism analysis. Therefore, in this paper, the seepage test of intact sandstone under different cyclic loads was carried out under low confining pressure. The test used sine waves to simulate low-frequency seismic waves, highlighting the permeability of underground water-bearing engineering rock mass with vibration frequency and amplitude under low-frequency source disturbance Variations and test results show that in the sandstone triaxial stress-strain curve, from the compacted section, the elastic section to the expansion section, the permeability of the rock gradually increases, and the sensitivity to cyclic load also increases. At the same time, the damage threshold of the rock gradually decreases, and the rock will break even in the elastic section. Under low confining pressure, the loading amplitude has a greater impact on rock permeability than the loading frequency under low-frequency cyclic loading. The loading frequency and loading amplitude can be comprehensively characterized by the average loading rate. Then, using nuclear magnetic imaging technology to change the microstructure of the rock sample before and after the test, the analysis shows that the effect of different cyclic load parameters on the permeability of the rock sample is actually obtained through the effect of force on pores and cracks. For dense rocks, The increase in permeability caused by cracks is even greater.
Research on the optimization of underground logistic paths based on the positive and negative bidirectional demand model
Authors: Xinyu Liu , Ai-lian Zhou 
Published: November 2020

Abstract
With the rapid development of e-commerce, urban ground distribution pressure is increasing daily with an increasing number of vehicles transporting goods and worsening urban traffic congestion. As an important public resource for urban transportation, the metro can effectively relieve the pressure on passenger transportation as well as become an active component of urban logistics and distribution operations. In this study, we establish a metro distribution model of urban underground logistics based on the positive and negative bidirectional demand model by exploring a new mode of urban underground logistics combining metro resources and urban logistics to achieve the lowest total cost. In the proposed model, we consider the positive and negative bidirectional logistic demands of each station and solve it using a genetic algorithm. Finally, by analyzing a case study, this paper demonstrates the feasibility and validity of the proposed model and algorithm.
Fortified length of the tunnel under the S-type fault displacement pattern
Authors: Guangxin ZHOU , Qian SHENG , Zhen CUI , Yalina MA , Tianqiang WANG 
Published: November 2020

Abstract
Many tunnels have been built in central and western China; these tunnels are facing serious damages of active faults. At present, the fortified length of tunnels remains to be solved under fault dislocation. To overcome this issue, a numerical calculation model is established on the basis of previous research on the numerical calculation and model test of tunnels across active faults, with Xiang Lushan tunnel project as the research background of the paper. The S-type fault displacement pattern is proposed, which is based on the deflection curve of the support of the fixed beam at both ends under the uneven settlement. The influence of S-type and linear fault displacement patterns on tunnel lining is investigated using the finite difference method. Meanwhile, through the orthogonal test of fault factors at different levels, the influence rule of the multi-factor combination of faults on the fortified length of the tunnel under the S-type fault displacement pattern is obtained. Results reveal that the S-type fault displacement pattern, compared with the linear displacement pattern, can eliminate the stress singularity at the boundary of the fault zone. Therefore, the S-type fault displacement pattern is more reasonable and can be used as the selection of fault displacement pattern. In addition, the fortified length of the tunnel ranges from 1.1 L to 2.0 L (L is the fault width), which is the result of the orthogonal test. The most influential factor for the fortified length of the tunnel is the angle between the fault strike and the tunnel axis, whereas the least influential factor is the fault dip angle. This research provides a reference for the fortified range of the tunnel crossing fault with certain practical significance.
New planning and design concept for urban underground spaces based on geo-environmental factors
Authors: Xu Hui , Li XiaoZhao , Fan XiaoQiu 
Published: November 2020

Abstract
As the urbanization in China advances, urban underground spaces are vigorously developed through large-scale projects. However, the development of underground spaces often proceeds without prior scientific planning and design. City planners who fail to consider geo-environmental factors tend to design nonholistic blueprints that may cause serious problems. The development of an underground space is irreversible because underground resources are currently deemed highly valuable. Therefore, scientific planning must be conducted before the construction and launch of underground space projects. This study adopts a new concept of underground space planning and design and analyzes unfavorable geo-environmental factors, such as sand liquefaction and soft soil, which affect the development of underground spaces. The development mode of the underground space suitable for the geological environment in the study area is proposed. Based on the new concept of planning and design, this work considers a case study in Guangdong Province as a reference for the development mode, depth, and function of underground space in the study area. The findings of this study provide some new planning and design ideas for the development and utilization of underground spaces.
Analysis of deformation characteristics of a tunnel in layered soft rocks with considering the effect of bedding
Authors: Ren Weitao , Qiang Sihan , Wang Xuehai , Tian Yun , Li Zhe 
Published: November 2020

Abstract
The layered soft rock tunnel is affected by the combination of layering and geostress, and it is easy to cause large deformation disaster. Based on the Weiwu high-speed Minxian tunnel, the influence of bedding on the stress and deformation characteristics of sandstone and carbon slate is studied in this paper. The calculation results show that the influence of bedding on the deformation of sandstone and carbonaceous slate is significant. If the influence of bedding is not considered in the process of tunnel deformation prediction, the deformation of surrounding rock will be seriously underestimated. The influence of bedding on the deformation distribution of surrounding rock is related to the strength of bedrock. For sandstone, the strength of bedrock is high, and the deformation and failure of surrounding rock is mainly caused by shear failure of layer, and its deformation distribution and magnitude It is obviously affected by the layered production. When the angle between the bedding and the maximum principal stress direction of the ground stress is 45°, the deformation amount reaches the maximum value. For the layered carbonaceous slate, due to the low strength of the bedrock, the surrounding rock has obvious crushing damage zone after the tunnel excavation, and the layered occurrence has little influence on the deformation value and distribution of the surrounding rock. The maximum deformation orientation of the surrounding rock is basically perpendicular to the direction of the maximum principal stress of the geostress.
Model experiment study on the stability mechanisms of box culvert excavation faces under the effect of pipe roof in a shallow bury
Authors: Xie X Y , Jiang C Z , Zhou B , Dai Q , Zhang Z , Liu F Z 
Published: November 2020

Abstract
The pipe roof box culvert construction method is widely used in short-distance crossing projects. The shallow buried tunnel can reduce the wiring length, thus saving on the project’s construction costs. However, if not handled properly, roof collapse may occur in the tunnel. In this study, we created a model experiment design based on the Tianlin Road pipe roof box culvert project and conducted an experiment involving a pipe roof box culvert excavation surface stability model under different bury depths and pipe roof stiffness levels as well as a support plate moving forward or backward. This was done to explore the process of the excavation face instability and the development mechanism of ground deformation. The excavation face support plate was moved during the experiment to simulate the failure process of the excavation face limit equilibrium state. The DIC binocular camera and the fiber Bragg grating fiber were used to monitor the surface deformation and pipe roof deformation, respectively. The experiment results reveal the environmental influence law of the supper shallow buried pipe roof box culvert construction method and the failure shape of the excavation surface. The results further indicate that the development of the surface deformation of the under-excavation gradually changes from “straight” to “parabolic” with the change of the stiffness of the pipe roof. Furthermore, without the pipe roof, both the deformation value and the ground deformation under the over-excavation do not exceed 63.4% and 20.6%, respectively. The maximum vertical deformation of the over-excavation pipe roof is located at about 1 H of the excavation surface, and the maximum deformation of the under-excavation occurs at a distance near 2 H. The results of the model experiment can provide guidance in the application of the pipe roof box culvert construction method under supper shallow buried conditions.
Study on upper limit solution and its application on bearing capacity of rock slope foundation
Authors: Li Shulin , Liu Yinchi , Tang Chao , Cao Yun , Zhang Jianlin , Peng Fuhua 
Published: November 2020

Abstract
The determination and analysis of the bearing capacity of a slope foundation has become an important research topic in foundation design theory. To explore the ultimate bearing capacity of the rock foundation adjacent to a slope on the basis of the shear failure mode of a rock foundation on a semi-infinite plane, the failure mode of the rock foundation near the slope was established by analyzing the failure mechanism of the Bell solution. The upper limit theorem of limit analysis was used to build a velocity field allowable for maneuvering. Using this method, the ultimate bearing capacity of the Sandaozhuang open-pit mine was analyzed and calculated. The results show that the foundation load of the mine is less than the allowable bearing capacity; hence, the building on the slope meets the requirements of foundation bearing capacity. At the same time, this paper uses this method and existing research methods to compare and analyze this project with others, proving the rationality and feasibility of the proposed method. This paper further explores factors affecting the ultimate bearing capacity, such as the horizontal setback distance of the footing from the edge of the slope and the dip angle. It is concluded that the ultimate bearing capacity increases with increases in the distance to the slope and decreases in slope angle. The study also shows that the calculations developed and proposed in this paper for the bearing capacity of the rock foundation adjacent to the slope are reasonable and feasible, can be applied to the calculations of the bearing capacity of rock foundations near the slope, and have guiding significance for the project.
Calculation Method for Unstable Rock Stability based on Dominant Fissure Model
Authors: Zhou Y T , Shi S W , Tang H M , Wang L F 
Published: November 2020

Abstract
In accordance with in-situ exploration and years of experience in unstable rock-related design, this paper states that the Mohr-Coulomb model is insufficient for the selection of the shear strength parameters of the dominant fissure of unstable rocks. Therefore, a JRC-JCS model of dominant fissure for three types of unstable rocks was established, which is more applicable to construction practice. Based on this model, calculation methods were obtained for the three types of unstable rocks, and the stability coefficient expressions of the unstable rocks were determined. The stability of five typical unstable rocks in Wanzhou District, Chongqing Municipality, China, namely, W12, W22, W59, W4, and W16, was calculated by these methods. As indicated by the calculation results, the unstable sliding rock W12, unstable toppling rock W22, and unstable falling rock W4 are stable, while the unstable toppling rock W59 and unstable falling rock W16 remain unstable and thus need reinforcing. These calculation results are relatively in line with the actual situation, according to a verification by in-situ monitoring from 2003 to 2013. This further verifies the practicality and applicability of the above calculation methods, which are based on the dominant fissure model. These methods also offer a theoretical basis for the amendment of the local standard, namely, Chongqing’s design specification for prevention and control projects of geological hazards (DB50/5029-2004), in terms of calculation methods for unstable rock stability.
Study on the deformation mechanism of abutment slope and its influence on the dam during the impoundment of high arch dam
Authors: Wang X W , Zhuang W Y , Liu Y R , Xue L J , Cheng L , Yang Q 
Published: November 2020

Abstract
The deformation of abutment slope during impoundment poses great challenges to the working behavior and long-term safety of the arch dam. According to the monitoring data of impoundment and slope, slope deformation, valley width change, and arch dam chord length change are systematically analyzed and studied. It is pointed out that the deformation of the dam body and foundation is an irreversible plastic deformation and is evidently correlated with impoundment. Based on the unsaturated effective stress principle of fractured rock mass and the action mode of the reservoir basin pressure, the deformation mechanism of abutment slope has been discussed. The large-scale 3D nonlinear finite element model is established based on numerical analysis, and the deformation mechanism during impoundment and the effect of the effective stress change on the displacement and stress of the dam body are analyzed. The results indicate that effective stress can elucidate the valley contraction to some extent and that the contribution of the reservoir basin pressure is small. Slope deformation is beneficial to the dam displacement to some extent. Moreover, it has a negligible influence on the dam surface stress. However, the junction of the dam and foundation needs to be given special attention.