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Rockfall seismic features analysis based on in situ tests:frequency, amplitude, and duration
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作者 Liang FENG Veronica PAZZI +2 位作者 Emanuele INTRIERI Teresa GRACCHI Giovanni GIGLI 《山地科学学报:英文版》 SCIE CSCD 2019年第5期955-973,共19页
In the seismic event classification,determining the seismic features of rockfall is significantly important for the automatic classification of seismic events because of the huge amount of raw data recorded by seismic... In the seismic event classification,determining the seismic features of rockfall is significantly important for the automatic classification of seismic events because of the huge amount of raw data recorded by seismic stations in continuous monitoring. At the same time, the rockfall seismic features are still not completely understood.This study concentrates on the rockfall frequency content, amplitude(ground velocity), seismic waveform and duration analysis, of an artificial rockfall test at Torgiovannetto(a former quarry in Central Italy). A total of 90 blocks were released in the test, and their seismic signals and moving trajectories were recorded by four tri-axial seismic stations and four cameras, respectively. In the analysis processing,all the artificial rockfall signal traces were cut separately and the seismic features were extracted individually and automatically. In this study, the relationships between a) frequency content and impacted materials, b) frequency content and the distance between block releasing position and seismic station(source-receiver distance) were discussed. As a result, we found that the frequency content of rockfall focuses on 10-60 Hz and 80-90 Hz within a source-receiver distance of 200 m, and it is well correlated with impacted material and source-receiver distance. To evaluate the difference between earthquake and rockfall, 23 clear earthquake signals recorded in a seven month-long continuous seismic monitoring, carried out with the four seismic stations, were picked out, according to the Italian national earthquakes database(INGV). On these traces we performed the same analysis as in the artificial rockfall traces, and two parameters were defined to separate rockfall events from earthquake noise. The first one, the amplitude ratio, is related to the amplitude variation of rockfall between two stations and is greater than that of earthquakes, because of the higher attenuation occurring for rockfall events, which consists in high frequencies whereas for earthquakes it consists 展开更多
关键词 ROCKFALL SEISMIC noise ANALYSIS Fourier TRANSFORM SEISMIC events classification Time-series ANALYSIS SEISMIC monitoring
轻型木结构抗震性能试验及设计评估新方法研究进展 预览
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作者 尹犟 刘朋 +2 位作者 陈伯望 王解军 张翰文 《工程抗震与加固改造》 北大核心 2019年第2期101-108,共8页
轻型木结构由于其节能环保,舒适耐久,且抗震性能良好,在世界范围内大量营建,因而其抗震性能及设计评估越来越受到重视。本文系统介绍了轻型木结构抗震领域的最新研究进展,重点分析了影响轻型木剪力墙受力性能的关键因素及低周反复加载... 轻型木结构由于其节能环保,舒适耐久,且抗震性能良好,在世界范围内大量营建,因而其抗震性能及设计评估越来越受到重视。本文系统介绍了轻型木结构抗震领域的最新研究进展,重点分析了影响轻型木剪力墙受力性能的关键因素及低周反复加载机制。综述了近年来国内外开展的轻型木结构房屋足尺振动台试验研究现状,尤其是国外NEES-Wood和NEES-Soft等前沿木结构项目的研发进展。总结了目前国际上几种最新研发的轻型木结构基于性能的抗震设计、评估方法,指出该类方法是未来木结构抗震工程领域的发展方向。已有研究结果表明:以位移为主要参考指标的抗震设计可以保证结构安全可靠,而基于损伤的方法对于轻型木结构的抗震评估尤为适用。 展开更多
关键词 木剪力墙 抗震 轻型木结构 基于性能的抗震设计和评估
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深地震反射剖面资料去噪关键技术 预览
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作者 彭仁艳 张明 +2 位作者 刘文峰 余锋 董旭光 《当代化工研究》 2019年第3期38-39,共2页
深反射地震剖面技术以其探测深度大、分辨高、准确性可靠等优势被作为研究地球深部构造的关键技术,但是,由于品质低、面波干扰强等原因,对深反射地震数据处理的改进一直是地球物理学家关注的热点和难点。本文以SL盆地深地震反射剖面数... 深反射地震剖面技术以其探测深度大、分辨高、准确性可靠等优势被作为研究地球深部构造的关键技术,但是,由于品质低、面波干扰强等原因,对深反射地震数据处理的改进一直是地球物理学家关注的热点和难点。本文以SL盆地深地震反射剖面数据常规处理为例,介绍了深地震反射剖面资料去噪关键技术,以作参考。 展开更多
关键词 去噪 面波 地震 深地震反射
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Characteristics of the Seismic Waves from a New Active Source Based on Methane Gaseous Detonation 预览
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作者 WANG Weitao WANG Xiang +7 位作者 MENG Chuanmin DONG Shi WANG Zhigang XIE Junju WANG Baoshan YANG Wei XU Shanhui WANG Tao 《中国地震研究:英文版》 CSCD 2019年第2期354-366,共13页
Active seismic sources are critical for obtaining high resolution images of the subsurface.For active imaging in urban areas,environment friendly and green seismic sources are required.In present work,we introduce a n... Active seismic sources are critical for obtaining high resolution images of the subsurface.For active imaging in urban areas,environment friendly and green seismic sources are required.In present work,we introduce a new type of green active source based on the gaseous detonation of methane and oxygen.When fired in a closed container,the chemical reaction,i.e.gaseous detonation,will produce high pressure air over 150 MPa.Seismic waves are produced when high pressure air is quickly released to impact the surroundings.The first field experiment of this active source was carried out in December,2017 in Jingdezhen,Jiangxi Province,where a series of active sources were excited to explore their potential in mine exploration.In current work,we analyzed the seismic waves recorded by near-field accelerators and a dense short-period seismic array and compared them with those from a mobile airgun source,another kind of active source by releasing high pressure air into water.The results demonstrate that it can be used for high resolution near surface imaging.Firstly,the gaseous detonation productions are harmless CO2 and water,making it a green explosive source.Secondly,the dominant seismic frequencies are 10-80 Hz and a single shot can be recorded up to 15 km,making it suitable for local structure investigations.Thirdly,it can be excited in vertical wells,similar to traditional powder explosive sources.It can also act as an additional on-land active source to airgun sources,which requires a suitable water body as intermediate media to generate repeating signals.Moreover,the short duration and high frequency signature of the source signals make it safe with no damage to nearby buildings.These make it convenient to excite in urban areas.As a new explosive source,the excitation equipment and conditions,such as gas ratio,sink depth and air-releasing directions,need further investigation to improve seismic wave generation efficiency. 展开更多
关键词 ACTIVE SOURCE SEISMIC WAVES METHANE DETONATION SOURCE Green SEISMIC SOURCE
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Sparse-Spike Deconvolution Promoting Frequency Dependent Seismic Stratigraphic Analysis and an Application 预览
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作者 LIU Chang 《地质资源与工程:英文版》 2019年第1期1-8,共8页
Low-frequency components of seismic data tend to characterize thicker litho-stratigraphic units, while high-frequency components tend to characterize thinner isochronous-stratigraphic units. Thus, frequency dependent ... Low-frequency components of seismic data tend to characterize thicker litho-stratigraphic units, while high-frequency components tend to characterize thinner isochronous-stratigraphic units. Thus, frequency dependent interpretation can help to achieve fine sedimentary sequence analysis. However, in current seismic sedimentology method, a certain frequency profile generated by frequency filtering, loses some stratum reflection information, which is out of the limited frequency band. To achieve real frequency dependent stratum reflection profiles with whole stratum information, a time-varying sparse-spiking deconvolution based method is proposed in this paper. A synthetic example and a real delta progradation example show the accuracy and effectiveness of proposed method. 展开更多
关键词 Sparse-spike DECONVOLUTION frequency dependent interpretation SEISMIC STRATIGRAPHIC ANALYSIS SEISMIC sedimentology
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The influence of irregular seafloor topography on the seismic wave field and migration imaging 预览
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作者 Fuxing Han Kun Wang Jianguo Sun 《海洋学报:英文版》 SCIE CAS CSCD 2019年第3期151-158,共8页
One of the problems experienced in marine geophysical exploration is that the layered features in the migration imaging profile are blurred and the seismic energy reflected is weaker in the middle or lower parts. In t... One of the problems experienced in marine geophysical exploration is that the layered features in the migration imaging profile are blurred and the seismic energy reflected is weaker in the middle or lower parts. In this study we model the seismic wavefield records in the undulating seafloor when there is both a slight change and significant change in seafloor topography to analyze its influence on the seismic reflection data and migration imaging profiles. We compare and analyze the wave field records collected at the same point on the original and modified velocity models, and the cross-bonding resulting migration imaging profiles. The results show that whether the seismic reflection data collection is performed along the direction of the survey line or against the direction of the survey line, slight changes in the seafloor topography have little effect on the wave field records and the migration profile, while significant changes in the seafloor topography have great effect on both the wave field records and migration profile. 展开更多
关键词 SEAFLOOR TOPOGRAPHY SEISMIC wave field SEISMIC REFLECTIONS MIGRATION imaging
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Pseudo-dynamic Test and Elasto-plastic Seismic Response Analysis of RC-CFST Composite Frame of Traditional Architecture 预览
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作者 Gaoyi Xu 《智能建筑研究》 2019年第1期119-139,共21页
Pseudo-dynamic tests are carried out on a traditional style building reinforced concrete (RC)- concrete filled steel tube (CFST) composite frame model with a scale ratio of 1/2 under seismic waves such as El Centro wa... Pseudo-dynamic tests are carried out on a traditional style building reinforced concrete (RC)- concrete filled steel tube (CFST) composite frame model with a scale ratio of 1/2 under seismic waves such as El Centro wave, Taft wave, Lanzhou wave and Wenchuan wave. The natural vibration frequency, acceleration, displacement and strain of the model are obtained. The failure process, restoring force characteristic curve and deformation capacity of the model structure are analyzed. The research shows that: Cottage is the first anti-seismic defense line of the model structure;With the increase of the peak acceleration of the input seismic wave, the natural frequency of the frame model decreases, and the acceleration amplification coefficient gradually decreases. The restoring force characteristic curve of the model structure presents a certain degree of "pinching" effect. The strain analysis shows that the longitudinal reinforcement of the gold column yields before the longitudinal reinforcement of the eave column. Cottage and concrete columns are the main energy dissipation components of the model structure. Based on the experimental results, the finite element analysis software SAP2000 is used to analyze the elastic-plastic seismic response of the test model frame. The calculated results are in good agreement with the experimental results. The calculation and analysis results show that the hinge order of the model frame is as follows: two sides of Cottage, bottom of golden column, bottom of eaves column, bottom of golden column CFST column and bottom of eaves column CFST column. Under the action of El Centro wave with a peak acceleration of 0.70g, the limit elastic-plastic interlayer displacement angle of the model column frame is close to the limit specified in the code, which indicates that the frame structure has a high seismic safety reserve. 展开更多
关键词 TRADITIONAL Style ARCHITECTURE RC-CFST Composite FRAMEWORK Pseudodynamic Test SEISMIC Erformance ELASTO-PLASTIC SEISMIC Response Analysis
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Intensity Distribution of the Mojiang MS 5. 9 Earthquake in Yunnan in 2018 预览
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作者 LU Yongkun ZHOU Yang +2 位作者 DAI Boyang YANG Jianqiang YAN Hang 《中国地震研究:英文版》 CSCD 2019年第1期74-85,共12页
The distribution of the intensity of the Mojiang MS5. 9 earthquake in Yunnan Province is expounded, and the damage characteristics of buildings and the damage ratio and seismic damage index of various building structu... The distribution of the intensity of the Mojiang MS5. 9 earthquake in Yunnan Province is expounded, and the damage characteristics of buildings and the damage ratio and seismic damage index of various building structures in each intensity area are compared with those of The Chinese Seismic Intensity Scale. The main basis and method of seismic intensity assessment are discussed in this paper. It is concluded that:① The seismic intensity should be based on the earthquake damage of the housing structure, which takes up a high ratio in the seismic intensity assessment. It is recommended that seismic intensity is estimated by calculating the average seismic damage index.② The highest intensity of the Mojiang MS5. 9 earthquake is Ⅷ degrees, with the long axis trending in the north-west direction. The area above Ⅶ degrees is 5,180km^2 .③ The intensity distribution of the Mojiang MS5. 9 earthquake meets the national standard and the distribution law of seismic intensity in Yunnan. 展开更多
关键词 Mojiang MS5. 9 EARTHQUAKE SEISMIC INTENSITY DAMAGE RATIO SEISMIC DAMAGE index
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Dynamic Response of 100m, 200m, 300m Lattice Domes with LRB Seismic Isolator 预览
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作者 Dong-il Choi Da-jin Kim Kang-geun Park 《土木工程与建筑:英文版》 2019年第8期523-537,共15页
The objective of this study is to analyze the seismic response characteristics of 100 m, 200 m, 300 m spanned lattice domes under both horizontal and up-down ground motion of El Centro earthquake. For the analysis of ... The objective of this study is to analyze the seismic response characteristics of 100 m, 200 m, 300 m spanned lattice domes under both horizontal and up-down ground motion of El Centro earthquake. For the analysis of earthquake response of lattice domes, the time history analysis is used for the estimation of the dynamic response. Horizontal and up-down earthquake ground motions cause a large asymmetric vertical deformation in the large spatial domes. This study is to investigate the seismic characteristics of lattice domes for eigenvalue modes, displacement and acceleration response. The earthquake response of lattice domes with LRB (lead rubber bearing) isolation device by the horizontal and up-down combined ground motion is significantly reduced for the asymmetric vertical deformation and accelerations of domes. 展开更多
关键词 300m dome seismic isolation response reducing effect time history analysis seismic ground motion
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Mechanical properties and associated seismic isolation effects of foamed concrete layer in rock tunnel 预览
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作者 Shaosen Ma Weizhong Chen Wusheng Zhao 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第1期159-171,共13页
Foamed concrete has a good energy absorption capability and can be used as seismic isolation material for tunnels.This study aims to investigate the mechanical properties and associated seismic isolation effects of fo... Foamed concrete has a good energy absorption capability and can be used as seismic isolation material for tunnels.This study aims to investigate the mechanical properties and associated seismic isolation effects of foamed concrete layer in rock tunnel.For this,a series of uniaxial/triaxial compression tests was conducted to understand the effects of concrete density,confining stress and strain rate on the mechanical properties of foamed concrete.The direct shear tests were also performed to investigate the effects of concrete density and normal stress on the nonlinear behaviors of foamed concrete layer-lining interface.The test results showed that the mechanical properties of foamed concrete are significantly influenced by the concrete density.The foamed concrete also has high volumetric compressibility and strain-rate dependence.The peak stress,residual stress,shear stiffness and residual friction coefficient of the foamed concrete layer-lining interface are influenced by the foamed concrete density and normal stress applied.Then,a crushable foam constitutive model was constructed using ABAQUS software and a composite exponential model was also established to study the relationship between shear stress and shear displacement of the interface,in which their parameters were fitted based on the experimental results.Finally,a parametric analysis using the finite element method(FEM)was conducted to understand the influence of foamed concrete layer properties on the seismic isolation effect,including the density and thickness of the layer as well as the shear stiffness and residual friction coefficient of the interface.It was revealed that lower density and greater thickness in addition to smaller shear stiffness or residual friction coefficient of the foamed concrete layer could yield better seismic isolation effect,and the influences of the first two tend to be more significant. 展开更多
关键词 ROCK TUNNEL Foamed concrete SEISMIC ISOLATION LAYER SEISMIC ISOLATION mechanism
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Seismic wave input method for three-dimensional soil-structure dynamic interaction analysis based on the substructure of artifi cial boundaries 预览
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作者 Liu Jingbo Tan Hui +2 位作者 Bao Xin Wang Dongyang Li Shutao 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第4期747-758,共12页
The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident... The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the fi nite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave fi eld on the nodes of the substructure composed of elements that contain artifi cial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artifi cial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplifi ed by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verifi ed by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves. 展开更多
关键词 soil-structure dynamic interaction SEISMIC WAVE INPUT WAVE method EQUIVALENT INPUT SEISMIC loads SUBSTRUCTURE of artifi cial boundaries
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Numerical Study on the Effect of the Manila Seismic Tsunami on the Guangdong Coast--The Nonlinear Effects of Tides and Tsunamis 预览
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作者 CAO Yonggang LIU Changjian +4 位作者 LIU Tongmu FENG Yanqing LIU Yuqiang LIAO Shizhi CHEN Yizhan 《中国地震研究:英文版》 CSCD 2019年第1期97-111,共15页
The coupling numerical model between astronomical tide and tsunamis was built based on the data of the COMCOT model, which was verified by the Japan “3·11” tsunami. The tsunami source of the Manila seismic tsun... The coupling numerical model between astronomical tide and tsunamis was built based on the data of the COMCOT model, which was verified by the Japan “3·11” tsunami. The tsunami source of the Manila seismic tsunami was designed and computed to analyze the risk of tsunami which will happen in the Guangdong coast. According to the results, the maximum quantity of water increasing and the time of the tsunami arriving at the Guangdong seacoast were calculated. The coupling simulation between astronomical tide and tsunamis has significant meaning for evaluating the risk and early-warning of tsunamis in the Guangdong coastal area. 展开更多
关键词 COMCOT model Earthquake TSUNAMI Manila SEISMIC zone Numerical simulation GUANGDONG COAST
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Seismic behavior of slab-structural wall junction of RC building 预览
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作者 Snehal Kaushik Kaustubh Dasgupta 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第2期331-349,共19页
In high seismic zone regions, slender reinforced concrete structural walls are commonly used in high-rise buildings as a main lateral load resisting element. These walls are very effective in limiting the lateral drif... In high seismic zone regions, slender reinforced concrete structural walls are commonly used in high-rise buildings as a main lateral load resisting element. These walls are very effective in limiting the lateral drift of the building due to their large in-plane stiffness. However, the presence of floor slabs influences the behavior of the shear wall. Also, the current design requirements do not account for the presence of floor slabs. To understand the behavior of wall-slab junctions and address the shortcomings of the current design requirements, the influence of two parameters, namely(a) aspect ratio and(b) longitudinal reinforcement ratio on the behavior is studied numerically. It is observed that the presence of floor slabs at different levels tends to partition the wall into squat wall panels between two consecutive floors. The wall-slab junctions show large stress concentrations arising from the strut action in the squat panels. It is also observed that the floor slabs can get significantly damaged near the wall-slab junction for lower vertical reinforcement ratios in the wall. Thus, the current codeprescribed minimum reinforcement in shear walls is not sufficient and needs to be revisited at for improved performance. 展开更多
关键词 RC WALL building wall-slab JUNCTION SEISMIC damage nonlinear STATIC analysis
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轻钢复合夹芯板墙构造及抗震性能研究 预览
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作者 于庆峰 胡敏 《钢结构》 2019年第5期72-76,共5页
针对低层轻钢结构住宅房屋,提出了一种新的夹芯复合板墙形式,夹芯墙内外层分别采用50 mm厚的火山渣混凝土,内外墙设置钢筋网,中层保温板采用150 mm厚的挤塑聚苯乙烯板(XPS),设置钢桁架与钢腹杆提高整体性;设计了复合板墙板与板之间的水... 针对低层轻钢结构住宅房屋,提出了一种新的夹芯复合板墙形式,夹芯墙内外层分别采用50 mm厚的火山渣混凝土,内外墙设置钢筋网,中层保温板采用150 mm厚的挤塑聚苯乙烯板(XPS),设置钢桁架与钢腹杆提高整体性;设计了复合板墙板与板之间的水平缝、垂直缝与阳角缝连接形式,采用预埋件与焊接在钢梁上的角钢螺栓连接形式将夹芯板墙固定于钢框架上;对夹芯板墙与钢框架进行有限元模拟抗震性能运算,研究了夹芯板墙与钢框架在单螺栓连接与双螺栓连接方式下的破坏机理。 展开更多
关键词 轻钢住宅 夹芯板墙 抗震 预埋件
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Site-Specific Zonation of Seismic Site Effects by Optimization of the Expert GIS-Based Geotechnical Information System for Western Coastal Urban Areas in South Korea
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作者 Han-Saem Kim Chang-Guk Sun Hyung-Ik Cho 《国际灾害风险科学学报:英文版》 CSCD 2019年第1期117-133,共17页
Earthquake-induced disasters are often more severe over soft soils than over firm soils or rocks owing to the seismic site effects related to the amplification of ground motion. On a regional scale, such differences c... Earthquake-induced disasters are often more severe over soft soils than over firm soils or rocks owing to the seismic site effects related to the amplification of ground motion. On a regional scale, such differences can be estimated by spatially predicting the subsurface soil thickness over the entire target area. Generally, soil deposits are deeper in coastal or riverside areas than in inland regions. In this study, the seismic site effects in the coastal metropolitan areas of Incheon and Bucheon, South Korea, were assessed to provide information on seismic hazards. Spatial prediction of geotechnical layers was performed for the entire study area within an advanced GIS framework. Approximately 7500 existing borehole records in the Incheon and Bucheon areas were gathered and archived into a GIS database. Surface geotechnical data were acquired from a walk-over survey. Based on the optimized geo-data, spatial zoning maps of site-specific seismic response parameters, based on multiscale geospatial modeling, were created and presented for use in a regional seismic mitigation strategy. Seismic zonation was also performed to determine site coefficients for seismic design over the entire target area and to compare them with each other. We verified that the geotechnical data based spatial zonation would be useful for seismic hazard mitigation. 展开更多
关键词 COASTAL urban areas Geodata Geostatistical spatial ZONATION SEISMIC SITE effects SITE classification South Korea
Rockburst management in Canadian hard rock mines 预览
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作者 B.P.Simser 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第5期1036-1043,共8页
Rockburst is a complex mining-induced phenomenon that remains difficult to be quantified.In particular,geological conditions contributing to rockbursts are more variable than those in many conventional engineering app... Rockburst is a complex mining-induced phenomenon that remains difficult to be quantified.In particular,geological conditions contributing to rockbursts are more variable than those in many conventional engineering approaches.Faults,intact rock properties,and other rock mass conditions vary,sometimes,within small distance.Stress levels that store energy or drive structures can change with geological complications.For example,faults may channel stress between the void and the discontinuity,and/or alter the local stress direction.High-strength rock masses may be very massive at shallow depth,allowing for large/stable excavations.The same rock type may store excessive strain energy at depth or high mineral extraction,and lead to rockbursts.More robust ground support systems that can bear dynamic loading are now commonplace in mining industry.A typical approach would be able to evaluate rockburst potential,and selectively deploy more robust ground support systems.Rockburst resistant support is more expensive in installation than most support systems designed for gravity loading.Thus,an excessively conservative risk assessment can affect both direct support costs and productivity.As mines continue to go deeper,selective use of burst-prone support may not be an optimal choice,and pervasive installation may become necessary.This implies a need to maintain a reasonable installation speed,and the time to get to deep orebodies is a major economic factor.This paper shows field examples of rockbursts to highlight some of the complex issues related to the rockburst.A multi-tiered risk mitigation approach is used for rockburst conditions.Examples of risk reduction strategies are given and some examples from a deep hard rock mine are used to illustrate the relative success of the strategies.Given that some residual risks to worker safety remain,discussion is presented on where more research or process improvements would be beneficial. 展开更多
关键词 ROCKBURST DYNAMIC SUPPORT SEISMIC MONITORING
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Volumetric changes in the focal areas of seismic events corresponding to destress blasting 预览
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作者 P.Konicek J.Schreiber L.Nazarova 《矿业科学技术学报:英文版》 CSCD 2019年第4期541-547,共7页
The typical development of total volumetric change in the focal areas of seismic events,corresponding to destress blasting,is characterized as an explosive phase followed by an implosive phase and with alternating add... The typical development of total volumetric change in the focal areas of seismic events,corresponding to destress blasting,is characterized as an explosive phase followed by an implosive phase and with alternating additional phases following on from that.In a few cases,a non-typical development of volumetric change was identified,where the first phase was implosive and the second phase,explosive.This development is mainly typical for induced seismic events recorded during mining,not for destress blasting.Seismic events were recorded during longwall mining in the Czech part of the Upper Silesian Coal Basin,where the destress blasting technique is used as a rockburst prevention active measure.Kinematic source processes in the focal areas of selected seismic events were analyzed by the seismic moment tensor inversion method,as well as by studying geomechanical rock mass conditions at the localities of the seismic events.The main goal of the analysis was to attempt to identify the reasons for non-typical development of volumetric changes in these cases.Volumetric changes were analyzed for seismic events with energy greater than 104 J,recorded in the period of time from 1993 to 2009(1109 events).80%(891)of the recorded seismic events were induced seismic events that were registered during longwall mining and 20%(218)corresponded to destress blasting events.Research shows that the main reason for the non-typical development of volumetric changes in the focal areas of seismic events is an association with destress blasting in the rock mass,which is very close to rock mass overstressing.The detonation of explosives in boreholes,which would dominate the first phase of volumetric changes,probably obscured stress release in the rock mass,as manifested in the first implosion phase of the volumetric changes in this case. 展开更多
关键词 Destress blasting Seismic event Volumetric changes Stress release
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Distribution of potential geological hazards and control factors in Qingdao offshore, China 预览
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作者 Ze Ning Man-man Lin +2 位作者 Yong Zhang Xiao-bo Zhang Xiang-huai Kong 《中国地质(英文)》 2019年第1期40-48,共9页
Engineering construction actively occurs in coastal zones, and these areas have numerous potential geological hazard factors. Since 2009, the development of geological surveys in sea areas has promoted extensive geoph... Engineering construction actively occurs in coastal zones, and these areas have numerous potential geological hazard factors. Since 2009, the development of geological surveys in sea areas has promoted extensive geophysical surveys in Qingdao offshore. In the present study, the types and distribution of potential geological hazard factors were systematically revealed using sub-bottom profile data, side-scan sonar data, and single-channel seismic data, among others. Based on previous research findings, the potential geological hazard factors are classified, and control factors in Qingdao offshore are discussed. The research results show that the primary potential geological hazards include active faults, buried paleo channels, shallow gas, irregular bedrock, eroded gullies, estuary deltas, tidal sand ridges, and seawater intrusion. In addition, neotectonic movement, sea level changes and sedimentary dynamic processes were the main factors that affected the distribution of geological hazards in Qingdao offshore. 展开更多
关键词 SOUTHERN Yellow Sea POTENTIAL GEOLOGICAL hazards BURIED paleo channels SINGLE-CHANNEL seismic Active FAULTS
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Pre-stack seismic waveform inversion based on adaptive genetic algorithm 预览
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作者 LIU Sixiu WANG Deli HU Bin 《世界地质:英文版》 2019年第3期188-198,共11页
Pre-stack waveform inversion, by inverting seismic information, can estimate subsurface elastic properties for reservoir characterization, thus effectively guiding exploration. In recent years, nonlinear inversion met... Pre-stack waveform inversion, by inverting seismic information, can estimate subsurface elastic properties for reservoir characterization, thus effectively guiding exploration. In recent years, nonlinear inversion methods, such as standard genetic algorithm, have been extensively adopted in seismic inversion due to its simplicity, versatility, and robustness. However, standard genetic algorithms have some shortcomings, such as slow convergence rate and easiness to fall into local optimum. In order to overcome these problems, the authors present a new adaptive genetic algorithm for seismic inversion, in which the selection adopts regional equilibrium and elite retention strategies are adopted, and adaptive operators are used in the crossover and mutation to implement local search. After applying this method to pre-stack seismic data, it is found that higher quality inversion results can be achieved within reasonable running time. 展开更多
关键词 GENETIC algorithm adaptive PROBABILITY regional EQUILIBRIUM SEISMIC INVERSION
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Seismic performance evaluation of typical dampers designed by Chinese building code 预览
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作者 Guo Wei Wu Jun +2 位作者 Hu Yao Li Yunsong Yang T.Y. 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第2期433-446,共14页
Adding dampers is a commonly adopted seismic risk mitigation strategy for modern buildings, and the corresponding design procedure of dampers has been well established by the Chinese Building Code. Even though all typ... Adding dampers is a commonly adopted seismic risk mitigation strategy for modern buildings, and the corresponding design procedure of dampers has been well established by the Chinese Building Code. Even though all types of dampers are designed by the same procedure, actual seismic performance of the building may differ from one to the others. In this study, a nine-story benchmark steel building is established, and three different and typical types of dampers are designed according to the Chinese Building Code to realize structural vibration control under strong earthquake excitation. The seismic response of the prototype building equipped with a viscoelastic damper, viscous damper and buckling-restrained brace(BRB) subjected to 10 earthquake records are calculated, and Incremental Dynamic Analysis(IDA) is performed to describe progressive damage of the structure under increasing earthquake intensity. In the perspective of fragility, it shows that the viscoelastic damper has the highest collapse margin ratio(CMR), and the viscous damper provides the best drift control. Both the BRB and viscoelastic dampers can effectively reduce the floor acceleration responses in the mid-rise building. 展开更多
关键词 CHINESE building design code viscoelastic DAMPER VISCOUS DAMPER buckling-restrained BRACE seismic response FRAGILITY analysis
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