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Effect of slope angle on fractured rock masses under combined influence of variable rainfall infiltration and excavation unloading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第10期16卷 4154-4176页

作者： Xiaoshuang Li Qihang Li Yunmin Wang Wei Liu Di Hou Chun Zhu School of Urban Construction Changzhou UniversityChangzhou213164China College of Civil Engineering Qilu Institute of TechnologyJinan250200China School of Resources and Safety Engineering Chongqing UniversityChongqing400044China Sinosteel Maanshan General Institute of Mining Research Co.Ltd. Maanshan243000China Guizhou Survey and Design Research Institute for Water Resources and Hydropower Guiyang550001China School of Earth Sciences and Engineering Hohai UniversityNanjing210098China

Intense precipitation infiltration and intricate excavation processes are crucial factors that impact the stability and security of towering and steep rock slopes within mining *** primary aim of this research was to investigate the progression of cumulative failure within a cracked rock formation,considering the combined effects of precipitation and excavation *** study was conducted in the Huangniuqian eastern mining area of the Dexing Copper Mine in Jiangxi Province,*** engineering geological investigation was conducted,a physical model experiment was performed,numerical calculations and theoretical analysis were conducted using the matrix discrete element method(Mat-DEM),and the deformation characteristics and the effect of the slope angle of a fractured rock mass under different scenarios were *** failure and instability mechanisms of the fractured rock mass under three slope angle models were *** experimental results indicate that as the slope angle increases,the combined effect of rainfall infiltration and excavation unloading is reduced.A novel approach to simulating unsaturated seepage in a rock mass,based on the van Genuchten model(VGM),has been *** to the vertical displacement observed in a similar physical experiment,the average relative errors associated with the slope angles of 45,50,and 55were 2.094%,1.916%,and 2.328%,***,the combined effect of rainfall and excavation was determined using the proposed ***,the accuracy of the numerical simulation was *** findings contribute to the seepage field in a meaningful way,offering insight that can inform and enhance existing methods and theories for research on the underlying mechanism of ultra-high and steep rock slope instability,which can inform the development of more effective risk management strategies.

关键词： Open-pit to underground excavation Rainfall infiltration Similarity simulation Numerical simulation Image recognition slope angle

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Impact of the slope angle of hummocks on the ride-up of finger ice in the Liaohe Estuary

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Acta Oceanologica Sinica 2013年第8期32卷 12-15页

作者： KONG Xiangpeng CHEN Naxin Environmental Science and Engineering College Dalian Maritime University Mathematics Department Dalian Maritime University

The ride-up and pile-up of sea ice have effects on the ice load of marine structure. The ride-up angle is an important parameter to study the process of ride-up and to determine the possibility of the ride-up to occur. Some conclusions about the ride-up angle are drawn based on field-survey data in this paper. Thirty hummocks with full structure, formed by 0.4-1.6 cm ice layers, were investigated in the Liaohe Estuary of the north of Liaodong Bay. After analyzing the cross-sections of the pile-up body, some concfusions on the ride-up angle are reached. The results indicate that whether the ride-up occurs or not is associated with the slope angle of the hummock. If the slope angle is greater than 10.31°, the ride-up can take place. With the development of riding-up and piling-up, if the slope angle increases to 40.0°, the climbing-up process will stop and the drifting ice begins to accumulate in front of the hummock. The climbing process does not continue until a new slope angle, which is less than 28.0°, is formed. Meanwhile, the forming process of hummocks, which are made up of 10.0 cm or 22.0 cm ice layers, is proved to follow the rule.

关键词： sea-ice riding-up slope angle the Liaohe Estuary

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Numerical study on gas production via a horizontal well from hydrate reservoirs with different slope angles in the South China Sea

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Deep Underground Science and Engineering 2024年第2期3卷 171-181页

作者： Tingting Luo Jianlin Song Xiang Sun Fanbao Cheng Madhusudhan Bangalore Narasimha Murthy Yulu Chen Yi Zhao Yongchen Song School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhouChina Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhanChina Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of TechnologyDalianChina Faculty of Engineering and the Environment University of SouthamptonSouthamptonUK

It is important to study the effect of hydrate production on the physical and mechanical properties of low-permeability clayey–silty reservoirs for the largescale exploitation of hydrate reservoirs in the South China *** this study,a multiphysical-field coupling model,combined with actual exploration drilling data and the mechanical experimental data of hydrate cores in the laboratory,was established to investigate the physical and mechanical properties of low-permeability reservoirs with different slope angles during 5-year hydrate production by the depressurization method via a horizontal *** result shows that the permeability of reservoirs severely affects gas production rate,and the maximum gas production amount of a 20-m-long horizontal well can reach186.8 m3/day during the 5-year hydrate *** with smaller slope angles show higher gas production *** depressurization propagation and hydrate dissociation mainly develop along the direction parallel to the ***,the mean effective stress of reservoirs is concentrated in the near-wellbore area with the on-going hydrate production,and gradually decreases with the increase of the slope *** from the effective stress distribution law,the total reservoir settlement amount first decreases and then increases with the increase of the slope *** maximum settlement of reservoirs with a 0°slope angle is up to 3.4 m,and the displacement in the near-wellbore area is as high as2.2 m after 5 years of hydrate *** is concluded that the pore pressure drop region of low-permeability reservoirs in the South China Sea is limited,and various slope angles further lead to differences in effective stress and strain of reservoirs during hydrate production,resulting in severe uneven settlement of reservoirs.

关键词： effective stress low‐permeability reservoirs natural gas hydrate production numerical simulation settlement slope angle the South China

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Seismic responses of slopes with different angles in coral sand

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Journal of Mountain Science 2021年第9期18卷 2475-2485页

作者： ZHANG Yan-ling DING Xuan-ming CHEN Zhi-xiong WU Qi WANG Cheng-long College of Civil Engineering Taiyuan University of TechnologyTaiyuan 030024China College of Civil Engineering Chongqing UniversityChongqing400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing400045China

This paper investigates the seismic responses of slopes in coral sand taken from a reef island in the South China Sea.A series of shaking table model tests were conducted to explore the responses of soil acceleration,excess pore pressure,and slope displacement for three slope angles(5°,10°,and 15°).The results show that the excess pore pressure ratio of the slope decreases due to an increase in the initial shear stress when the slope angle *** acceleration response of the soil increases with the increase of the slope *** slope displacement presents substantial increments as the excess pore pressure ratio *** addition,the lateral movement,and slope settlement present substantial increments as the slope angle *** liquefaction is observed under a dynamic excitation of 0.2 g in the coral sand *** a dynamic excitation of 0.4 g,the site liquefies quickly,the acceleration amplification factor decreases,and the lateral movement and the settlement of the slope surface both increase compared with that under 0.2 g *** the slope with an angle of 15°at 0.4 g,the flow distance of the sand strip increase by 289.47%compared with that in the 5°*** lateral movement of the slope surface near the water level line is substantially larger than that away from the water *** largest settlement is observed near the middle section of the slope(below the water level)under a dynamic excitation of 0.2 *** contrast,the largest settlement under a dynamic excitation of 0.4 g occurs at the top of the slope.

关键词： Coral sand slope angle Shaking table tests Seismic response Liquefaction

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Preliminary estimation of rock-fall lateral dispersion by laboratory test

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第12期15卷 3343-3351页

作者： Louis Ngai Yuen Wong Zhicheng Tang Department of Earth Sciences The University of Hong KongHong KongChina Faculty of Engineering China University of GeosciencesWuhan430074China

Lateral dispersion significantly directs the assessment of rockfall hazard and design of countermeasures. In the present study, the dependence of lateral dispersion on different controlling factors has been systematically evaluated by performing laboratory tests using three different rock block types, namely circular block, and two types of elliptical block. The three types of rock block are released onto an inclined surface with the identical initial status. Parallel, anti-parallel, and oblique impact tests set at slope angles of 22.5° and 45°are conducted to study the block-slope interaction of rockfall. Lateral dispersion of rockfall is less influenced by the block shape for the oblique impact, while the post-impact behaviors are greatly affected by the block shape. The key factors influencing the deviation of the post-impact trajectory direction are the slope angle (θ) and direction difference (Δφ). An empirical model is then developed to characterize the deviation distribution of lateral dispersion by 5th and 95th percentile values with the inclusion of the two key factors. Linear function can be used to describe the 5th percentile boundary, while hyperbolic function is good for the 95th percentile boundary, which need to be validated by field tests in the subsequent research.

关键词： Rockfall Block shape slope angle Oblique impact Lateral dispersion

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Effects of laser beam divergence angle on airborne LIDAR positioning errors

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Journal of Beijing Institute of Technology 2012年第2期21卷 278-284页

作者：姜利芳蓝天顾美霞倪国强 Key Laboratory of Photo-electronic Imaging Technology and System Beijing Institute of Technology

The influence of laser beam divergence angle on the positioning accuracy of scanning airborne light detection and ranging （LIDAR） is analyzed and simulated. Based on the data process and positioning principle of airborne LIDAR, the errors from pulse broadening induced by laser beam di vergence angle are modeled and qualitatively analyzed for different terrain surfaces. Simulated results of positioning errors and suggestions to reduce them are given for the flat surface, the downhill of slope surface, and the uphill surface.

关键词： Kairborne light detection and ranging (LIDAR) positioning error laser beam divergenceangle slope angle scan angle

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A theoretical method to characterize the resistance effects of nonflat terrain on wind fields in a parametric wind field model for tropical cyclones

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Tropical Cyclone Research and Review 2024年第3期13卷 161-174页

作者： Gengjiao Ye Pingzhi Fang Hui Yu Shanghai Typhoon Institute of China Meteorological Administration ShanghaiChina Key Laboratory of Numerical Modeling for Tropical Cyclone/CMA ShanghaiChina School of Geography Sciences East China Normal UniversityShanghaiChina Asia-Pacific Typhoon Collaborative Research Center ShanghaiChina

Traditionally,an empirical speed-up factor was introduced to reflect the effects of nonflat terrain on near-surface wind *** this paper,the resistance effects of nonflat terrain are considered by introducing the terrain drag coefficient in the parametric wind field model for tropical cyclones(TCs)with a theoretical *** effects on wind fields are investigated in complex areas along the coastal zone in China under TC *** results show that the terrain drag coefficient is the function of the slope angle and is sensitive to the spatial *** including the resistance effect of nonflat terrain,the TC intensities weaken overall during landfall,with a slight enhancement near the coastal *** wind speeds outside the radius of the maximum wind speed decrease,while the wind speeds within the radius of the maximum wind speed *** the TC eye and the radius of maximum wind speed shrink,which is more obvious when the TC center is entirely over *** a result,the location and magnitude of the maximum wind speed are affected by the nonflat *** changed structure of the wind fields demonstrates the necessity of considering the effects of nonflat terrain in simulating the wind fields under TC conditions.

关键词： Parametric wind field model Tropical cyclones Nonflat terrain slope angle Terrain drag coefficient Pressure coefficient

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Reduction of rainfall infiltration in soil slope using a controllable biocementation method

Biogeotechnics

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Biogeotechnics 2023年第2期1卷 1-16页

作者： Xiaohua Pan Jian Chu Liang Cheng School of Civil and Environmental Engineering Nanyang Technological UniversitySingapore 639798Singapore School of Earth Sciences and Engineering Nanjing UniversityNanjing 210023China School of Environmental and Safety Engineering Jiangsu UniversityZhenjiang 212013China A

Reasonable control of rainwater infiltration rate can ensure that soil slope will not fail due to rapid infiltration of rainwater in heavy rainfall,and at the same time,more rainwater can be infiltrated in light rainfall to meet the water demand of animals and *** this study,based on microbial-induced calcium carbonate precipitation(MICP)technique,a controllable bio-method for rainfall infiltration of soil slope was *** have a comprehensive understanding the relationship among the rainwater infiltration control capacity,biocement treated soil permeability,slope angle and rainfall intensity,a series of physical modelling experiments of rainfall diversion on slopes with three types of soils and three slope angles were carried out in the presence of various rainfall *** results indicated that the proposed bio-method had the ability of controlling rainwater infiltration in term of varying rounds of biocement spraying *** general,it was found that the rainwater infiltration decreases with the increase in slope angle and rainfall *** the worst case of smallest slope angle(15°)and lightest rainfall intensity(n=50 mm/h),more than 82.6%,92.2%and 84.4%of rainwater were prevented from infiltration into the MICP treated natural sand,fine sand and medium sand,respectively,while the untreated soils were not able to prevent the rainwater infiltration at *** corre-sponding maximum local uniaxial compressive strength for the MICP treated natural sand,fine sand and medium sand,respectively,were found to be 2.3 MPa,2.0 MPa,2.6 MPa,whereas the flexural stresses were 0.46 MPa,0.33 MPa,0.67 MPa,which could resist rainfall droplet impact ***,the proposed bio-method showed good rainwater infiltration control capacity and high bearing strength against the impact of heavy rainfalls,suggesting a good potential to mitigate the rainfall-induced landslides.

关键词： Soil slope slope angle Rainfall Infiltration control Biocement

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Theoretical Study of Seed Movement in Cotton Seeds Selection Device

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Engineering（科研） 2021年第10期13卷 544-553页

作者： Obidov Avazbek Sultonov Mirzaolim Department Engineering and Technology Namangan Institute of Engineering and Technology Namangan Uzbekistan

The aim of the research work is to increase the yield of cotton fiber by improving the processing technology of germinated seeds, to improve the quality indicators of seeds and lint. In order to achieve this goal, a mesh surface device was created to sort the seeds into fractions. Sorting technology was developed on this device and operating modes were determined. In addition, the law of surface distribution of the fractions separated from the cotton stream moving along the surface of the net was determined, and based on the results of practical and theoretical research, a mode of sorting of cotton seeds was developed. As a result, differential equations of the law of oscillation of seeds on parallel bases, taking into account the angle of inclination for the movement of cotton seeds on the sorting surface, were constructed and programmed on a computer to construct the trajectory of seeds. On the basis of the laws of motion, the optimal value of the angle of inclination on the horizontal, which gives the state of sorting of seeds, as well as the values of the amplitude and frequency of vibrations, was determined.

关键词： Cotton Seeds slope angle Sorting Device Fractions Letuchka Cotton Ginning Amplitude Frequency Ginning Sorting Sections Brush Drum Movement

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