bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on Bell solution of the ultimate bearing capacity for slope rock foundation and its application
Authors: Tang Chao , Li Shu Lin , Liu Yin Chi , Cao Yun , Zhang Jian Lin , Peng Fu Hua 
Published: November 2020

Abstract
Limited studies focused on the slope rock foundation, and the application results of several methods differ considerably. In this paper, the coefficients of the Bell solution are first reduced by the length ratio of the sliding failure plane and the vertical area ratio of the overloaded soil. Then, the Hoek–Brown criterion for nonlinear failure is introduced, and the tangential line tangent to the Hoek–Brown failure criterion curve is calculated to replace the original M-C failure criterion. A method for determining the instantaneous friction angle and instantaneous cohesion under normal stress with the Bell solution failure mode is established, and the relationship between the instantaneous friction angle, instantaneous cohesion, and normal stress are discussed. The instantaneous friction angle decreases with the increase in normal stress, whereas the instantaneous cohesion increases with normal stress. The influence of geological strength index (GSI) and rock empirical parameter mi
on bearing capacity coefficients N
σ, N
q, and Nγ
are also comprehensively analyzed. The coefficients increase with GSI and mi
. In addition, the method is used to analyze the bearing capacity of rock foundation of a high and steep slope in an open-pit mine, and the results are compared with the slip-line method, which considers Hoek–Brown failure criterion and finite-element numerical simulation. The comparison demonstrates the acceptability of the proposed method.
Toppling deformation characteristics and mechanism of bank slope in Xiluodu Hydropower Station, China
Authors: Yi Xiaoyu , Feng Wenkai , Wu Zhuolin , Dun Jiawei , Zhou Yongjian , Li Shuangquan 
Published: November 2020

Abstract
Xiluodu Hydropower Station of the Jinsha River started impounding water in May 2013. In June 2013, five cracks occurred on the bank slope of the Xingguang village. By the end of 2019, the number of slope cracks has increased to 13. Based on the detailed field investigation, deformation monitoring, and drilling and adit investigation, the deformation characteristics of the Xingguang bank slope are studied. The results indicate that the Xingguang bank slope is a steep bedding toppling deformation, which is further intensified by the impoundment operation of the reservoir. Monitoring data show that the Xingguang bank slope does not deform toward the free direction, but inclines upstream, and the deformation gradually increases from the top to bottom. According to the change degree of slope surface displacement, the Xingguang bank slope can be divided into four deformation areas in the plane: intensified strong deformation area, strong deformation area, moderate deformation area, and slight deformation area. Based on the deformation degree of the rock mass, the vertical section is divided into four deformation zones: intensified strong toppling deformation zone, strong toppling deformation zone, moderate toppling deformation zone, and slight toppling deformation zone. Further study reveals that the thin-layer rock mass structure is the material basis of the bank slope toppling deformation, the landform formed by the cutting of the Jinsha River Valley provides favorable boundary conditions for the toppling deformation, and the strong unloading rebound of the rock mass is the key factor of the bank slope toppling deformation.
Analytical model of the deformation response of bedding slopes to excavation on the basis of Mindlin’s strain solution
Authors: Cong LI , Rongtang Zhang , Bo Lu , Jie-bing ZHU , Dong-dong XU , Jie-sheng LIU , Ping Zeng 
Published: November 2020

Abstract
To reveal the deformation law and mechanism of bedding slopes under excavation unloading, an unloading rebound model of slope deformation is established on the basis of Mindlin’s strain solution, and a bedding-slip model of slope deformation is deduced on the basis of the Kalhaway constitutive model. Combining the two models, this study presents a computational model for the deformation response of bedding slope excavation. This model can reflect the mechanism of excavation unloading and the characteristics of rock mass structure. The reliability of the model is verified by comparing the calculated results of the analytical model with the experimental results in the laboratory. On this basis, the influences of excavation angle, excavation depth, and stratum thickness are analyzed by using several calculation examples. The calculation results show that the deformation induced by excavation increases with the increase in excavation angle or depth and decreases with the increase in stratum thickness. The excavation response of bedding slopes is mainly affected by the effect of unloading and the slip of the structural plane. Moreover, the unloading effect is controlled by the amount of excavation, and the rebound deformation of slopes is approximately linearly correlated with excavation volume. Bedding slip is affected by many factors because the increase in excavation angle or the amount of rock stratum leads to the increase in slip deformation. The proposed model can provide a basis for the deformation mechanism of bedding slopes under excavation.
Characteristics Analysis of landslides, collapses and debris flows occurred from 2010-2019 in China
Authors: Chunrong Yin , Yuan Li , Xueyan Qu , Bing Han , Bin Tong , Xu-dong Yang , Hao Fang , Yanling Zhang 
Published: November 2020

Abstract
Based on the national geological disasters database in China, this paper presents the temporal and spatial distribution characteristics, triggering factors and losses caused by land-slides, collapses and debris flows in China from 2010 to 2019: (1) landslides, collapses and de-bris flows are usually developed extensively in the transitional areas between the three terraces and the areas between mountains and plains; landslides, collapses and debris flows of large scale are more developed in regions near active faults, and the majority of these disasters still remain active; (2) the temporal development of landslides, collapses and debris flows follows a general trend of normal distribution, and the high-incidence season is from May to August. The high-intense period slightly shift from the south to the north in China; (3) precipitation and earthquakes are important triggering factors of landslides, collapses and debris flows. The magnitude of the earthquake and properties of seismogenic faults affects the distribution and the scale of landslide, collapse and debris flow; (4) in the past decade, landslides, collapses and debris flows have caused 5,968 people dead or missing, and caused direct economic losses of over 40.98 billion yuan. According to the above research, this paper puts forward the key periods and areas for prevention of sudden geological disasters in the future in China.
Model test of cantilevered double-row anti-sliding piles in steeply slipping landslides
Authors: Xianchun MA , Yang XIAO , Lu MENG 
Published: November 2020

Abstract
The mechanism governing pile–soil and rock interaction in steeply slipping landslides is quite different from that observed in gently slipping landslides. In particular, the mechanism responsible for the double-row anti-sliding pile stress is notoriously complex. Using the K285 landslide along the Neijiang-Liupanshui railway route as an example in our study, we demonstrated that pile safety in steeply slipping landslides was based on the similarity principle. A physical model interaction test between the double-row anti-sliding piles and the landslide was performed to determine the impact of factors such as the failure mode as well as pile stress, bending moment, and head (top) displacement on the safety of a project site. Herein, we noted that the landslide thrust located behind the lower row was about ½- to 1 times that of the upper row when the distance between two rows of anti-sliding piles was about the same as the pile length, assuming that the same loading conditions were used. Also, the resistance of the sliding mass in front of the upper row piles had a maximum value, and the maximum bending moment of the lower row was about

1
3

- to 1 times that of the upper row under the aforementioned assumptions. The results indicated that the anti-sliding pile heads should be 0.5–1.0 m higher than the ground surface around the piles and backfilled behind the piles. Additionally, the bedrock located before the piles adopted a “wedge” fracture with a depth corresponding to the position of the maximum bending moment. The associated fracture angle and depth were related to the friction angle of the bedrock and the inclination angle of the slipping surface. In conclusion, the study provided insight that will be useful for designing anti-sliding piles to mitigate the occurrence and impact of these types of landslides.
Node classification of urban underground logistics system
Authors: Xiao-qi Li , Ai-lian Zhou 
Published: November 2020

Abstract
With the development of artificial intelligence and internet of things technology, an underground logistics system will gradually become one of the novel ideas to alleviate urban traffic problems. Such a system consists of underground logistics nodes, but their classification is a key problem in the planning of an underground logistics network. On the basis of the analysis of the demand and supply characteristics of underground logistics, the underground logistics node determination model for multi-objective planning was established for logistics in which the nodes were graded and solved by CPLEX. Finally, this paper verified the rationality and validity of the model, method, and algorithm through the calculation analysis of samples. Thus, this work provides some theoretical support for the classification of urban underground logistics nodes.
Case Study: Effect of Natural Fracture on Stimulation Strategy in Keshen Tight Gas
Authors: Zhang Y , Chen Z , Yang X , Qiao Y , Teng Q , Wang Y 
Published: November 2020

Abstract
Aimed at problems of poor fracturing effects of fracture-network acid fracturing in three wells in the Keshen 5 block, a fractured and tight gas reservoir in Tarim Oilfield, the mechanical activity of natural fractures was studied. The fractures in this block were divided into three types: fully-filled, semi-filled, and unfilled. The analysis of the correlations showed that the correlation of the number of fully-filled fractures and absolute open flows (AOF) is poor, while the correlation between the number of unfilled and semi-filled fractures and AOF is the best. Core samples with different types of fractures were tested using conventional triaxial compression methods, and the experimental results showed that the friction coefficient of the fully-filled fracture is close to that of semi-filled fracture, while the cohesion of fully-filled natural fractures is close to that of intact rocks, which is much greater than that of semi-filled fractures. The effective stress test results shows that the effective stress coefficient of fully-filled natural fracture rock samples is lower than that of semi-filled fractures. Using Mohr–Coulomb theory to calculate the natural fracture mechanics of high-production wells and low-production wells, the results show that low-production wells are mainly fully-filled fractures, most of which are not activated, so the production is low; while high-production wells are semi-filled and unfilled fractures, most of which can be activated, so the production is high. Based on this, for a well dominated by fully-filled fractures, it is recommended to use conventional gel fracturing to replace the fracture-network acid fracturing process. The stimulation practice of two wells has proven the validity of this strategy. The filling degree of natural fractures affects the increasing production and choice of stimulation process. This may be a relatively new understanding and may provide insights to stimulation strategy decisions for other fractured tight reservoirs in the world.
Three-dimensional geomechanical model of creep behavior on wellbore casing in the composite salt–gypsum formation
Authors: Li Shiyuan , Li Fuyao , Du Xianfei , Qiu Yufan 
Published: November 2020

Abstract
According to statistics, a certain proportion of the world’s oil and gas resources are stored under the salt rock in the sedimentary basin. These reservoirs are located in formations called “pre-salts,” which are below the salt formations. They are widely found in the Sichuan, Tarim, and Changqing oilfields and in West Africa, offshore Brazil, the Gulf of Mexico, and the North Sea. The salt–gypsum layer exhibits a rheological property, which has a significant influence on casing damage. Creep deformation of the composite salt–gypsum formation occurs over time. Moreover, it applies excess stress on the wellbore casing, which can lead to casing damage. In this study, triaxial experiments are conducted on samples of salt–gypsum composite rock, and a power-law creep constitutive model is created. In the experiment, room temperature and humidity conditions are applied. Three types of loading, including axial and confining pressures, are separately applied on the samples, including the confining pressure (5 MPa) and the axial pressures (20, 25, and 30 MPa). From the experimental results, the relation between creep strain and time can be obtained, and a power-law creep model can be matched as the constitutive equation, which indicates that the strain rate is dependent on differential stress and temperature. The Abaqus finite element method software is used for establishing a 3D geomechanical model with formation stress and wellbore pressure to evaluate the life expectancy of wellbore casing. According to the triaxial rock experiment in the laboratory and according to field data, the mechanical parameters of the salt–gypsum formation and the parameters of the pre-salt reservoir are obtained, respectively. The results demonstrate that the von-Mises stress on the wellbore casing in the salt–gypsum layer increases during the production period. Meanwhile, the creep deformation of the formation also increases and applies extra loading on the casing, which is prone to exceed the strength and damage. Moreover, in this research, the discontinuous stress and deformation at the interface of the composite salt–gypsum formation, on which few researchers have studied until now, can be quantitatively described. The results indicate that the stress on the wellbore casing in the pre-salt layer is different, that is, the stress abruptly changes at the interface between pre-salt and salt–gypsum formation. The results also show the discontinuous creep deformation at the interface and that the casing is prone to shear collapse. Considering the sudden change in the stress at the interface of the formation is important. These results can be utilized to establish a casing design and for the analysis of wellbore integrity. For instance, the composite salt–gypsum layer should pass through the design of the double-layer casing and enable the thick-walled casing to increase its strength.
Geotechnical behavior of soft dredger fill and deep sea soft clay
Authors: Wang Lei , Lei Huayang , Bo Yu , Jiang Mingjing , Wang Peng , Liu Min 
Published: November 2020

Abstract
A full understanding of the geotechnical properties of deep sea soil is necessary for ocean engineering construction, and the basis is the evaluation and testing of undisturbed deep sea soil. Therefore, to investigate the geotechnical properties of deep sea soil, a series of experimental tests were conducted in this study. Furthermore, the test results of the deep sea soil were compared with that of the soft dredger fill. The results showed that deep sea soil comprised of high contents of clay minerals and fine particles as well as high compressibility and low strength. Compared with soft dredger fill, the mineral composition and microscopic characteristics of deep sea soil is greatly different, which is the main reason for the differences in their geotechnical properties. This study provides great support for understanding and evaluating geotechnical properties of the deep sea soil and provides an effective method for the preparation of deep sea soil samples.
Stability of submarine landslides by in situ observation
Authors: Xue Liang , Jia Yonggang , Hou Yankai , Liang Tianyang , Shan Hongxian , Shan Zhigang , Peng Peng 
Published: November 2020

Abstract
With the continuous expansion of human activities to the ocean and the development of marine engineering, the stability of submarine landslides has attracted increasing attention. Monitoring data of the stability of submarine landslides under the action of strong wind and waves remain lacking because of limited observation technology and complex real sea conditions. This paper reports the long-term and continuous stability monitoring of submarine landslides under the action of wind and waves in the seabed of the Zhujiajian landslide area of Zhoushan by using a self-developed observation equipment. Effective data were collected, and variations in the pore pressure and displacement of seabed under the action of wind and waves were analyzed. Then, problems related to the change of displacement of seabed under the action of waves were explored. A typhoon event occurred during the observation period, and the significant wave height increased significantly from about 0.1 m under calm sea conditions to 0.5 m. The excess pore pressure in the sediment of 1 m under the seabed fluctuated obviously under the action of waves, with an amplitude of 2–4 kPa. By contrast, the amplitude of excess pore pressure oscillation was about 0.5 kPa under calm sea conditions, and the wave enhancement significantly increased the excess pore pressure oscillation in shallow sediments. The displacement of 0.5 mm occurred from 12 m to 13.5 m under the seabed, and the rapid accumulation or large fluctuation of lateral displacement occurred at different depths during the three periods when the significant wave height peaked.
Application of Micro Earth Pressure Cells to Geomechanical Model Tests of Arch Dams
Authors: Senhao WANG , Yuan CHEN , Lin ZHANG , Baoquan YANG , Jianhua DONG , Tao SUN , Chong ZHANG , Xiaoqiang LIU 
Published: November 2020

Abstract
Geomechanical model tests are important in the evaluation of the stability of engineering rock masses, and they play a key role in the stability studies on arch dam abutments. To further analyze the instability failure process and mechanical characteristics of dam abutment rock masses, this study employed a stress monitoring system in the traditional strain and displacement monitoring to improve the comprehensiveness of test results. With their advantageous properties, including their small volume, high sensitivity, and strong stability, micro earth pressure cells can directly monitor stress changes in arch abutment rock mass during geochemical model tests. On the basis of the overloading method, this study applied micro earth pressure cells to a 2D geomechanical model test on the Yebatan arch dam to investigate the working performance of the arch dam and arch abutment at EL.2 750 m. In the test, the surface displacement monitoring system and micro earth pressure cells on both sides of the deep unloading belts of the left and right dam abutments were arranged to study the pressure changes at the arch abutment and the influence of the geological structure. The results showed that the measured stress value near the arch abutment was large and that the measured stress value greatly decreased after passing through the deep unloading belt. Class IVs of strongly relaxed rock masses in the left abutment exerted an obvious attenuation effect on the arch thrust while fault f29 (f74) greatly influenced the right abutment. The results were verified by the displacement test data. The application of micro earth pressure cells facilitated the direct observation and analysis of dam abutment stress and improved the completeness of the test results. Thus, the proposed approach provides a new idea for geomechanical model tests.
GNSS Multipath Errors Mitigation Algorithm Based on Observation Domain for Landslide Deformation Monitoring
Authors: Haibo He , Li Wang , Bao Shu , Yaohui Zhang , Long Li 
Published: November 2020

Abstract
The Global Navigation Satellite System (GNSS) real-time kinematic (RTK) technology is widely used for landslide deformation monitoring due to its precision and simplicity of its algorithm. However, GNSS signals are susceptible to multipath effects under complex circumstances such as terrain and surrounding vegetation. Reducing the impact of multipath errors and improving the RTK positioning accuracy is vital in ensuring accurate landslide monitoring in mountainous regions. The traditional method based on sidereal filtering in the coordinate domain only considers comprehensive multipath errors of all satellites, and the calculated time shift of coordinate sequence is not very accurate. In this paper, a sidereal filtering algorithm based on the double-difference residual in the GNSS observation domain is used for mitigating the multipath errors of landslide deformation monitoring in mountainous regions. First, we calculate the double-difference residuals of the observation in the previous cycle. Next, the empirical mode decomposition (EMD) filtering is used for denoising double-difference residual sequences. Based on the calculated period of the respective satellite, we use the residuals to correct the double-difference observation equation. Subsequently, we obtain the clean double-difference observations after mitigating multipath errors. Finally, the baseline coordinates of all monitoring stations can be calculated. The experimental results show that this method effectively improves the accuracy of GNSS landslide deformation monitoring in mountainous regions and the improved effect exceeds the traditional sidereal filtering algorithm in the coordinate domain.
Research, development, and field trial of the universal Global Navigation Satellite System receivers
Authors: ZHAO W Y , ZHANG M Z , Ma J , Qi G , Zhu S N , HUANG Z 
Published: November 2020

Abstract
Global Navigation Satellite System (GNSS) can provide continuous, high precision, and absolute displacement information on landslides. It can thus be used in landslide monitoring applications. However, the cost of high-precision GNSS is too high for large-scale deployment. From an application perspective, we reviewed the status and challenges of applying GNSS technology to landslide monitoring. We then investigated the data specification for a landslide monitoring GNSS receiver to better meet specified engineering requirements. We further developed prototype universal GNSS monitoring devices and deployed them in the Heitai area for testing. Approximately two months of testing indicated that the prototype universal GNSS devices well meet the engineering requirements, and the tested GNSS data are in good agreement with the crack data. The hourly monitoring GNSS solution achieves sub-millimeter level accuracy and can be used for extracting landslide information.