bluuebunny/crossref_metadata_2025_split huggingface dataset:
Movement Law of Overlying Strata with Loading Effect in the Large Space Structure of Deep Mines
Authors: Feng Cui , Zhaoyuan Lei , Tuanjie Li , Zhaohai Lv , Lei Li , shuai Dong 
Published: November 2020

Abstract
Under the action of high-stress field, overlying strata with load characteristics in large space structure formed by changes of working faces in deep mines intensifies the movement of the overlying strata on the working face, which may easily cause dynamic disasters at the working face. Considering the large space structure of deep mines and taking gob-side entry retaining as a breakthrough point, this study analyzes various types of overlying strata structures and their loading effects. The concept and differentiation method of deep “three layers” are introduced. The movement of the overlying strata with loading effect is analyzed by establishing a large-scale Flac3D numerical calculation model and on-site inspection. The results indicate that the “arch” structure formed by the working face shifts to the middle and rear parts of the working face under the influence of the large space structure, and the overlying strata continuously evolves upward during this process. Finally, the “arch” structures of the working face are integrated within the overlying strata to form a symmetrical structure. In the deep “three layers,” “Mk” provides the force source for normal weighing of the working face. “Mj” shifts the stress relief of the working face to the middle–rear position, which may easily cause strong strata pressure at the working face. The uniformly distributed load of “My” ensures the stress relief position at the working face. Through on-site monitoring, the disturbance range and stress of Working Face 418 with large mining height are greater than those of Working Face 416. The changes in pressure relief positions of the working face are as follows: ventilation roadway > middle > intake roadway.
Deformation monitoring of noncircular tunnels based on 3D laser scanning
Authors: Guo J F , Zong X , Xie X Y , Wang L , Zhai J L 
Published: November 2020

Abstract
Deformation plays an essential role in the safety control of tunnel construction, especially for tunnels with large deformation disasters. Consequently, tunneling professionals need practical ways to monitor tunnel deformation. However, traditional methods are not yet available for 3D monitoring. This study presents a technology for measuring tunnel deformation on using a 3D laser scanner. This technology includes an automatic noise removal algorithm based on spatial features and a measurement technology of absolute coordinates. For point clouds with different times of section with the same mileage, a point-to-point deformation analysis is performed based on the azimuth. Based on the standard grid of point clouds in the longitudinal and circumferential directions of the tunnel, an overall deformation cloud map of the noncircular tunnel is generated. The use of the proposed method in the construction of the Xinzai tunnel of the express connecting Jianshui and Yuanyang in Yunnan province allows engineers to obtain critical information about deformation. Compared with the traditional monitoring method, the proposed approach can meet engineering requirements well.
Field Tests and research of Large Deformation Control Measures for Soft Rock Tunnel with High Geostress
Authors: Sun Xiaoming , Zhang Bo , Zhang Yong , Qiao Xiaobing , Wang Zhijiao , Tao Zhigang 
Published: November 2020

Abstract
The Muzhailing highway extra-long tunnel is affected by high geostress, and during the construction, large deformation of soft rock frequently occurred. Taking this as the research background, the high-prestressed constant resistance and large deformation anchor cable support scheme was proposed. In the field test, the indicators of three support schemes were compared, including the convergence deformation of surrounding rock, the deep displacement of surrounding rock, the axial force of anchor cable and bolt, and the stress between primary support and surrounding rock. The field test results show that: under the support of bolts, the cumulative deformation of surrounding rock exceeded 1500 mm, and the primary support damage was serious; In the second scheme, under the support of 4 m and 5 m long constant resistance anchor cables, although the large deformation of surrounding rock was controlled, the cumulative deformation was about 600 mm; In the third scheme, under the support of 5 m and 10 m long constant resistance anchor cables, the cumulative maximum deformation of surrounding rock was reduced to 216 mm, and all the data of the field test were within the controllable range. Therefore, high prestressed constant resistance and large deformation anchor cable support measures can effectively control the large deformation of surrounding rock.
Stress-induced cracking performance of hard basalt in a large underground cavern based on multi-information observation
Authors: Jiang Quan , Xu Dingping , Zhao JinShuai , Li Shaojun , Wang Wei , Xu Jian 
Published: November 2020

Abstract
Overcoming the brittle cracking and the corresponding hard rock has become the key bottleneck challenge in the excavation of underground engineering with high geostress. To further understand the onsite cracking’s characteristics and the basic mechanism of hard rock, we carried out a detailed field monitoring action for basalt breaking behaviors in a large underground powerhouse by in situ investigation, digital borehole camera, multi-point deformation measurement, and real-time micro-seismic monitoring. On the basis of our observations, the inner cracking performances of surrounding rock embodied as discontinuous appearance and open of cracks during excavation, and these fractures were often parallel to the outline of the cavern and extended to the inner side because of the subsequent excavation disturbance. Corresponding numerical simulation indicated that the redistribution of rock stress induced local stress concentration and would result in the splitting break of basalt. Field complicated proof indicated that this stress-induced cracking of basalt belonged to the tensile break, and the macroscopic deformation of the surrounding was the result of the accumulation of abundant open deformation of discontinued cracks. This observed achievement can enrich our understanding of the cracking mechanism of hard rock and provide some key cures for optimization design for underground engineering construction under high geostress conditions.
Study on geotechnical engineering investigation method of strong karst deep backfill area in mountain area
Authors: Hao Liu , Maozhong Tian , Jinyang Liu 
Published: November 2020

Abstract
Guizhou Province is characterized as mountainous with few flat lands. It also features undulating terrains; widespread karst strata; large karst troughs; karst depressions and falling water caves; and well-developed underground karst caves, karst pipelines, and underground rivers. In such mountainous areas, large-scale construction of karst sites requires large-scale excavation and backfilling. The study site comprises several backfilled layers of 550 m thickness and features complex components and large thickness variations. The influence of the long-term seepage of surface water and groundwater is also apparent. However, the study site also exhibits an uneven settlement of deep backfilled layers and unstable karst foundation. The conventional survey method cannot identify effectively and comprehensively existing problems in engineering geology and hydrogeology according to the problems found in the investigation of large-scale building areas, municipal roads, urban rail transit, and university campuses. Through the combination of building engineering methods, such as new and old topographic and geomorphologic contrast methods, on-site geological surveys, karst hydrogeological surveys, borehole layout principle, drilling method, effective physical exploration test, field in-situ test, and indoor test, the scale and characteristics of karst development in the study site, changes in backfill thickness and material composition, and physical and mechanical properties of rock and soil mass are determined. The results provide comprehensive geotechnical data for the type selection, arrangement, and foundation scheme selection of structures. Through comprehensive analysis and summary, this work establishes a set of comprehensive geotechnical investigation methods for strong backfilled karst areas in mountainous regions. The results are expected to be applicable to other similar sites.
Spatial distribution characteristics of landslides in Xiluodu Reservoir Area
Authors: Pengcheng Su , Chun Ma , Jingjing Liu , Yong Li 
Published: November 2020

AbstractThere are many landslides in Xiluodu Reservoir Area. 161 landslides were interpreted to investigate. The key influential factors including the formation lithology, faults, rainfall, earthquake, reservoir water level and the Geodetecter methods was used to explore the relative impact of the factors and the interaction of the two factors on the spatial distribution of landslides. The results show that: (1) Due to the differences in the properties of different rock groups, the landslides show significant regional differences; (2) The landslides are mostly distributed in the range of 600~1200 m, 10°~40°, Ordovician-Silurian (O-S) strata, areas within 4 km of the fault, areas where the average annual rainfall is 800~900 mm and seismic peak ground acceleration of 0.15g; (3) There are 53 landslides affected by reservoir water. The effect is most obvious when the water level acts on the middle and front of the landslide. The effect time is gradually weakened with the annual deformation and stress adjustment; (4) Multi-factor interaction presents more clear relationship with the spatial distribution of landslides. The interaction of lithology and rainfall can explain 45.9 % of the spatial variation of landslides, which means that lithology and rainfall factors have the greatest influence on the spatial distribution of landslides. The results provide a certain basis for the prevention and control of landslides in Xiluodu Reservoir Area.
Integrated system of geophysical methods for shallow loose covering stratum exploration in the granite region in the northwest of Zhejiang Province, China
Authors: Fang Hao , Tong Bin , Du Xianxiang 
Published: November 2020

Abstract
The major triggering factor of the collapses, landslides, and debris flow in the northwest region of Zhejiang Province in China is the shallow loose covering stratum with a thickness of dozens of centimeters to dozens of meters generated by the intensive physical weathering process of granite. Therefore, accessing a three-dimensional model of the slope structure covering by the shallow loose stratum and quantifying its thickness and spatial distribution are very important in deepening one’s understanding of the failure mechanism and distribution features and improving the efficiency of geohazard prevention and mitigation. This study applies high-density electrical method, microtremor survey, artificial transient surface wave method, and ground-penetrating radar to explore the slope structure covered by the loose stratum. By validating and comparing the results obtained through engineering geological drilling, an integrated system of the geophysical methods for the shallow loose covering stratum is proposed herein with greater precision and suitability for the granite region in the northwest of Zhejiang Province. This integrated system of methods consists of geophysical exploration, followed by drilling for validation. Each individual method in the system can be applied with suitability evaluation and recommended parameters. The proposed system could also properly void shortage when only an individual method is used. The major conclusions obtained in this study are as follows: (1) the accuracy of the high-density electrical method in the dry condition could reach 85% or above, and in the rainy season, the test should be conducted 48 h after the rainfall; (2) the microtremor survey and artificial transient surface wave methods can achieve good results in the case of a complex climate condition or a large-area detection; (3) the ground-penetrating radar method can be used to discover the loose covering layer thickness with good precision (less than 5 m); and (4) the integrated method system is more applicable when the ground slope is less than 30°.
High-precision 3D real scene model construction method based on air-ground data combination
Authors: Yang Fei , Ma Chengrong , Zhang Bowen , Chen Xuannan , Cao Li , Li Changhong , Huang Yongliang 
Published: November 2020

Abstract
Due to low efficiency, low accuracy, and difficulty in intuitively realizing the real geological conditions for spatial data acquisition on mines and slopes, this study proposes the use of a 3D modeling method based on a combination of air and ground data. The method is based on Unmanned Air View (UAV) tilt photogrammetry data. In this article, 3D terrestrial laser scanning point cloud data is used as a supporting technique via control points to spatially fuse and improve the accuracy of the UAV tilt photogrammetry 3D model. This study uses the feature points to adjust the interior point coordinates of the UAV tilt photogrammetry 3D model. The application results show that the mining site model established by this method has high precision and processing efficiency. It can also display the overall characteristics of mines and provide a scientific basis for mining, exploration, measurement, and effective evaluation of slope stability.
Experimental study of blasting wave propagation in jointed rock mass and vibration reduction effect of barrier holes
Authors: Li Yashi , Zhao Rui , Zhu Jianbo 
Published: November 2020

Abstract
Blasting in underground rock opening could generate shock waves, propagating in surrounding rock mass and possibly leading to damage and instability of surrounding underground structures. Barrier holes are widely used in blasting vibration reduction. However, characteristics of blasting wave propagation in jointed rock masses have not been well determined, and the understanding of effect of barrier holes on vibration reduction is still at its infancy. To investigate the blast-induced wave propagation in jointed rock masses and vibration reduction effect of barrier holes, laboratory explosion tests were performed with the super dynamic strain test system and vibration monitor system. Results showed that the joint orientation has significant effects on the first-peak compressive strains in surrounding rock mass and adjacent opening. First-peak compressive strain of surrounding rock mass increases with decreasing scaled distance. The first-peak compressive strain on the wall of the adjacent underground opening is dependent on the characteristics of the adjacent underground opening. In addition, the dynamic responses of the surrounding rock mass are determined by the combined influence of the joint dip angle and location. The experimental results also indicated that barrier hole diameter has great effects on first-peak compressive strains of adjacent underground opening and the vibration-isolation rate of measuring points before and after barrier hole screen. With increasing barrier hole diameter, first-peak compressive strains and peak particle velocities (PPVs) significantly decrease and vibration-isolation rate of measuring points before and after barrier hole screen increases, indicating the vibration reduction effect of barrier hole increases. The findings in this paper could facilitate better understanding blasting wave propagation in jointed rock mass, and be helpful in vibration control of engineering explosions.
Coupled static and dynamic tensile property of granite
Authors: Man Ke , Liu Xiaoli 
Published: November 2020

Abstract
The principle of coupled static and dynamic loading is illuminated according to the basic principle of the SHPB, i.e., one-dimensional stress wave propagation and uniformity of the specimen. In the Tianhu area of Xinjiang Province, which is a preselected area for high-level radioactive waste geological disposal, a series of coupled static and dynamic loading was conducted in a borehole. The dynamic tensile strength could reach a maximum level when the axial tensile stress is about 50% of the static tensile strength. Meanwhile, as the axial tensile stress increases, the coupled static and dynamic tensile strength increases obviously, reaching about three times the static tensile stress and about 1.5 times the dynamic tensile strength. The failure model of the coupled test is a tensile failure pattern, which is the same as in the static tension and conventional dynamic loading test. Furthermore, through a series of coupled static and dynamic loadings, the strength of the rock specimen could be obtained under different kinds of axial tensile stress and dynamic loading. Thus, the critical value of the dynamic loading could be confirmed, which is useful for blasting excavation in deep geoengineering.
Shaking table test on the characteristics of seismic acceleration responses at the portal section of the loess tunnel
Authors: Zhao Tao , Liang Qingguo , Ma Xiaowen , Ai Shengjun , Zhou Wendi , Wang Lili 
Published: November 2020

Abstract
A large-scale shaking table test was conducted to study the dynamic response at the portal section of a tunnel based on the loess tunnel of the Baoji–Lanzhou high-speed railway as an engineering background. A wavelet packet transform method was applied to analyze seismic acceleration responses. The pattern of changes in energy in the loess tunnel under the seismic load was obtained. Results reveal that (1) the acceleration amplification factor of the slope surface increases with elevation, but a turn exists at the inverted arch of the tunnel because the stiffness of the tunnel is greater than that of the slope soil. As such, the tunnel elicits a certain protective effect on the slope soil below it. (2) The amplification effect of the internal slope soil decreases gradually outward, and the tunnel portal is affected by the amplification effect of the slope surface. The peak ground acceleration (PGA) of the tunnel vault is greater than that of the inverted arch of the tunnel. Thus, the vicinity of the tunnel vault should be the key seismic fortification area. (3) The loess layer causes an amplification effect on low-frequency-band seismic waves (0–12.51 Hz) and a filtering effect on the high-frequency-band seismic waves. The changes in the energy of the slope surface and the inside tunnel gradually stabilize as the seismic load increases. This study can provide a reference for the seismic fortification of the tunnel portal section of the loess slope–tunnel system under a seismic action.
Seismic analysis of a transition tunnel constructed with TBM and mining method
Authors: Yang Song , Li Ruozhou , Li Pengyuan , Wang Chao , Yu Fei , Yuan Yong , Yu Haitao 
Published: November 2020

AbstractA transition tunnel is generally built to connect a TBM tunnel and a mining tunnel, given the different cross sections associated with each construction method. The transition tunnel may be sensitive to earthquake damage since the tunnel cross-section and stiffness change along the tunnel axis. Studying the seismic performance of the transition tunnel structure, a subtle 3D finite element model is carried out. Comparing with the calculation results of SHAKE91, a reasonable non-reflective boundary condition is used. The concrete adopts an elastoplastic damage constitutive model, and the surrounding rock mass uses an elastoplastic constitutive model based on the Drucker-Prager yield criterion. The effects of different ground motion magnitudes and different types of seismic waves are calculated and analyzed through dynamic time-history method. The calculation results show that the impact range of the construction method butted composite lining section on the tunnel structure of the mine tunnel and the TBM tunnel is about 10m, and the reinforcement of the inner lining will cause a sudden change in the stress of the outside TBM tunnel structure. Moreover, the compressive stress of the surrounding rock and tunnel structure is small, and the structural damage mainly occurs in the area of the arch shoulder and arch foot.
Method of S Wave Identification: Application to Measured blasting vibration signals
Authors: Yang Zhaowei , Hu Yinguo , Liu Meishan , Wu Xinxia , Zhao Gen 
Published: November 2020

Abstract
S wave identification is an indispensable step in the process of deriving the dynamic parameters of rock masses, which are highly significant in guiding the design and construction of hydraulic engineering projects. However, it is difficult to identify S waves accurately because of 1) the influence of overlapping within the P wave coda and 2) the incomplete separation between S and P waves owing to the characteristic short distances of blasting seismic wave propagation. This paper presents a modified method for accurately identifying S waves at the engineering scale using blasting vibration signals. The proposed method combines the application of the short-time average zero-over rate with polarization analysis. By using the short time average zero-over rate, it is possible to effectively reduce the computational time while improving the computational efficiency. Polarization analysis is used to improve the accuracy of the method. A comparison of numerical identification and theoretical results revealed that the improved method is clearly capable of S wave identification with errors of less than 2%. To demonstrate the capability and accuracy of the proposed method, measured vibration signals were introduced to the Fengning pumped-storage power station and the S wave velocities obtained from the first arrival times were compared to obtain an estimated S wave velocity.
A coal burst model based on roof vibration and coal slippage
Authors: Han J , Jia D , Cao C , Zhu Z , Li Y 
Published: November 2020

Abstract
Rock burst poses a serious threat to mining, and its mechanism still needs to be studied. Statistics show that more than 85% of rock bursts occur in mining roadways. The authors investigated the mechanism of rock burst in the roadways by creating a finite elastic long beam dynamic model in longwall mining based on the elastic foundation theory. In this study, the fracture failure of the basic roof and the related dynamic effects are analyzed. The results indicate that the occurrence of the free vibration of the basic roof is caused by fracturing during the first face advance. It is also found that the vibration frequency increases and the period decreases with the increase in roof thickness. Furthermore, the strength and elastic modulus increase with the increase in roof hardness. The effect of a thick, hard roof on the coal mass is mainly reflected in the vibration of the roof above the coal seam. During free vibration of the roof, the stress applied by the roof on the coal mass decreases. Under the action of horizontal stress, the coal mass slips along the interface between the roof and coal mass, which may result in rock burst. The mode of the basic roof vibration and the viscoelastic properties of the coal mass significantly influence the vibration–slippage impact. With the increase in the strength, thickness, and horizontal stress of the roof, the possibility of sliding between the coal seam and the roof also increases, which may potentially result in rock burst. This mechanism may explain the occurrence of rock burst in large-scale coal bodies that move out in the roadway, which could provide a reference for the prevention and control of such phenomena.