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Analysis of the interaction between bolt-reinforced rock and surface support in tunnels based on convergence-confinement method 被引量:2
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作者 Zhenyu Sun Dingli Zhang +2 位作者 Qian Fang Yanjuan Hou Nanqi Huangfu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期1936-1951,共16页
To investigate the interaction of the bolt-reinforced rock and the surface support,an analytical model of the convergence-confinement type is proposed,considering the sequential installation of the fully grouted rockb... To investigate the interaction of the bolt-reinforced rock and the surface support,an analytical model of the convergence-confinement type is proposed,considering the sequential installation of the fully grouted rockbolts and the surface support.The rock mass is assumed to be elastic-brittle-plastic material,obeying the linear Mohr-Coulomb criterion or the non-linear Hoek-Brown criterion.According to the strain states of the tunnel wall at bolt and surface support installation and the relative magnitude between the bolt length and the plastic depth during the whole process,six cases are categorized upon solving the problem.Each case is divided into three stages due to the different effects of the active rockbolts and the passive surface support.The fictitious pressure is introduced to quantify the threedimensional(3D)effect of the tunnel face,and thus,the actual physical location along the tunnel axis of the analytical section can be considered.By using the bolt-rock strain compatibility and the rocksurface support displacement compatibility conditions,the solutions of longitudinal tunnel displacement and the reaction pressure of surface support along the tunnel axis are obtained.The proposed analytical solutions are validated by a series of 3D numerical simulations.Extensive parametric studies are conducted to examine the effect of the typical parameters of rockbolts and surface support on the tunnel displacement and the reaction pressure of the surface support under different rock conditions.The results show that the rockbolts are more effective in controlling the tunnel displacement than the surface support,which should be installed as soon as possible with a suitable length.For tunnels excavated in weak rocks or with restricted displacement control requirements,the surface support should also be installed or closed timely with a certain stiffness.The proposed method provides a convenient alternative approach for the optimization of rockbolts and surface support at the preliminary stage of tunnel design. 展开更多
关键词 Analytical model Longitudinal tunnel displacement Fictitious pressure Active rockbolts surface support reaction pressure Tunnel design
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Evaluation of Convolutional-Long Short-Term Memory Model in Predicting Surface Displacement of Underground Mines
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作者 Saviour Mantey Yao Yevenyo Ziggah Isaac Selasi Kojo Attipoe 《Advances in Remote Sensing》 2024年第3期73-88,共16页
Surface stability is essential in underground mines health management systems. Unexpected Surface displacement in underground mines could lead to loss of lives, injuries, and economic losses. To reduce or neutralise t... Surface stability is essential in underground mines health management systems. Unexpected Surface displacement in underground mines could lead to loss of lives, injuries, and economic losses. To reduce or neutralise the adverse effects of surface displacement, it is vital to monitor and accurately predict them and unravel their mechanisms. In recent years, Convolutional Neural Network (CNN) and Long Short-Term Memory (LSTM) have proven effective in predicting complex problems. However, CNN neglects the dynamic dependency of the input in the temporal dimension, which affects surface displacement features. The Convolutional-LSTM model can dynamically learn the temporal dependency among input features via the feedback connections in the LSTM to improve accurate captures of surface displacement features. This study focused on evaluating the C-LSTM model in predicting surface displacement of underground mines and assessed the predictive capabilities and generalisation strength of using hybridised ANN models. Geodetic and geotechnical data gathered from a Gold Mine in Ghana was used. The three models were tested on experimental data collected at Monitoring Scan Point 3. It was observed from the prediction output that all the methods could provide applicable and practical results. However, using indicators like root mean square error (RMSE) and correlation coefficient (R) in assessing the output of the prediction, the C-LSTM had the best prediction output. This study contributes to the advancement of accurate and efficient prediction of surface displacement of underground mines, ultimately enhancing and assisting safety operations. 展开更多
关键词 ANN CNN LSTM C-LSTM Underground Mines surface displacement
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Unraveling the influence of surface roughness on oil displacement by Janus nanoparticles
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作者 Yuan-Hao Chang Sen-Bo Xiao +2 位作者 Rui Ma Zhi-Liang Zhang Jian-Ying He 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期2512-2520,共9页
Janus nanoparticles(JNPs)possess great potential in recovering the residual oil from reservoirs,however,the fundamental interaction mechanisms among nanoparticles,the oil,and reservoir wall characteristics remain to b... Janus nanoparticles(JNPs)possess great potential in recovering the residual oil from reservoirs,however,the fundamental interaction mechanisms among nanoparticles,the oil,and reservoir wall characteristics remain to be elucidated.In this work,models of oil trapping grooves with different geometric features are subjected to molecular dynamics simulations for investigating the influences of roughness parameters on oil displacement dynamics by JNPs.Four key surface geometry parameters and different degrees of surface hydrophobicity are considered.Our results indicate that JNPs hold an outstanding performance in displacing residual oil on weakly to moderately hydrophobic surfaces.Overall,smaller entry and exit angles,the larger aspect ratio of the oil trapping grooves,and a bigger tip length of the rough ridges lead to superior oil recovery.Among the key geometric parameters,the aspect ratio of the oil trapping grooves plays the dominant role.These insights about the interaction of surface properties and JNPs and the resulting trapped oil displacement could serve as a theoretical reference for the application of JNPs for targeted reservoir conditions. 展开更多
关键词 Janus nanoparticles Oil displacement Enhanced oil recovery Molecular dynamics simulation Rough surface
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Surface Rupture and Co-seismic Displacement Produced by the Ms 8.0 Wenchuan Earthquake of May ^(12)th,2008,Sichuan,China:Eastwards Growth of the Qinghai-Tibet Plateau 被引量:58
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作者 DONG Shuwen ZHANG Yueqiao WU Zhenhan YANG Non MA Yinsheng SHI Wei CHEN Zhengle LONG Changxin AN Meijian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第5期938-948,共11页
An earthquake of Ms 8 struck Wenchuan County, western Sichuan, China, on May 12^th, 2008 and resulted in long surface ruptures (〉300 km). The first-hand observations about the surface ruptures produced by the earth... An earthquake of Ms 8 struck Wenchuan County, western Sichuan, China, on May 12^th, 2008 and resulted in long surface ruptures (〉300 km). The first-hand observations about the surface ruptures produced by the earthquake in the worst-hit areas of Yingxiu, Beichuan and Qingchuan, ascertained that the causative structure of the earthquake was in the central fault zones of the Longmenshan tectonic belt. Average co-seismic vertical displacements along the individual fault of the Yingxiu-Beiehuan rupture zone reach 2.514 m and the cumulative vertical displacements across the central and frontal Longmenshan fault belt is about 5-6 m. The surface rupture strength was reduced from north of Beichuan to Qingchuan County and shows 2-3 m dextral strike-slip component. The Wenchuan thrust-faulting earthquake is a manifestation of eastward growth of the Tibetan Plateau under the action of continuous convergence of the Indian and Eurasian continents. 展开更多
关键词 Ms 8.0 Wenchuan earthquake surface ruptures co-seismic displacement eastern Tibet
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Ground Surface Ruptures and Near-Fault,Large-Scale Displacements Caused by the Wenchuan Ms8.0 Earthquake Derived from Pixel Offset Tracking on Synthetic Aperture Radar Images 被引量:10
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作者 QU Chunyan SHAN Xinjian +5 位作者 LIU Yunhua ZHANG Guohong SONG Xiaogang ZHANG Guifang GUO Liming HAN Yufei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2012年第2期510-519,共10页
The 12 May 2008 Wenchuan Ms8.0 earthquake produced surface displacements along the causative fault, the Yingxiu-Beichuan Fault, which are up to several meters near the fault. Because of the large gradient, satellite s... The 12 May 2008 Wenchuan Ms8.0 earthquake produced surface displacements along the causative fault, the Yingxiu-Beichuan Fault, which are up to several meters near the fault. Because of the large gradient, satellite synthetic aperture radar (SAR) interferometric data are strongly incoherent; the usual SAR interferometry method does not allow such displacements to be measured. In the present study, we employed another approach, the technique based on pixel offset tracking, to solve this problem. The used image data of six tracks are from the Advanced Land Observing Satellite, Phased Array type L-band Synthetic Aperture Radar (ALOS/PALSAR) dataset of Japan. The results show that the entire surface rupture belt is 238 km long, extending almost linearly in a direction of 42°north-east. It is offset left laterally by a north-west-striking fault at Xiaoyudong, and turns at Gaochuan, where the rupture belt shifts toward the south by 5 km, largely keeping the original trend. In terms of the features of the rupture traces, the rupture belt can be divided into five sections and three types. Among them, the Beichuan-Chaping and Hongkou-Yingxiu sections are relatively complex, with large widths and variable traces along the trend. The Pingtong-Nanba and Qingping-Jingtang sections appear uniform, characterized by straight traces and small widths. West of Yingxiu, the rupture traces are not clear. North of the rupture belt, surface displacements are 2.95 m on average, mostly 2-3.5 m, with 7-9 m the maximum near Beichuan. South of the rupture belt, the average displacement is 1.75 m, dominated by 1-2 m, with 3-4 m at a few sites. In the north, the displacements in the radar line of sight are of subsidence, and in the south, they are uplifted, in accordance with a right-slip motion that moves the northern wall of the fault to the east, and the southern wall to the west, respectively. Along the Guanxian-Jiangyou Fault, there is a uplift zone in the radar line of sight, which is 66 km long, 1.5-6 km wide, and has vertical displacements of approximately 2 m, but no observable rupture traces. 展开更多
关键词 synthetic aperture radar interferometry incoherent zone surface displacement pixel offset Wenchuan earthquake
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Relationship between Meridional Displacement of the Monthly East Asian Jet Stream in the Summer and Sea Surface Temperature in the Tropical Central and Eastern Pacific 被引量:13
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作者 LIN Zhong-Da 《Atmospheric and Oceanic Science Letters》 2010年第1期40-44,共5页
Previous studies have shown that meridional displacement of the East Asian upper-tropospheric jet stream (EAJS) dominates interannual variability of the EAJS in the summer months.This study investigates the tropical P... Previous studies have shown that meridional displacement of the East Asian upper-tropospheric jet stream (EAJS) dominates interannual variability of the EAJS in the summer months.This study investigates the tropical Pacific sea surface temperature (SST) anomalies associated with meridional displacement of the monthly EAJS during the summer.The meridional displacement of the EAJS in June is significantly associated with the tropical central Pacific SST anomaly in the winter of previous years,while displacements in July and August are related to tropical eastern Pacific SST anomalies in the late spring and concurrent summer.The EAJS tends to shift southward in the following June (July and August) corresponding to a warm SST anomaly in the central (eastern) Pacific in the winter (late spring-summer).The westerly anomaly south of the Asian jet stream is a result of tropical central Pacific warm SST anomaly-related warming in the tropical troposphere,which is proposed as a possible reason for southward displacement of the EAJS in June.The late spring-summer warm SST anomaly in the tropical eastern Pacific,however,may be linked to southward displacement of the EAJS in July and August through a meridional teleconnection over the western North Pacific (WNP) and East Asia. 展开更多
关键词 meridional displacement East Asian jet stream tropical Pacific sea surface temperature meridional teleconnection
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Experimental investigation on shear strength deterioration at the interface between different rock types under cyclic loading
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作者 Qiong Wu Zhiqi Liu +6 位作者 Huiming Tang Liangqing Wang Xiaoxue Huo Zhen Cui Shiyu Li Bo Zhang Zhiwei Lin 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期3063-3079,共17页
The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake... The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake;however,rare work has been devoted to this subject due to lack of attention.In this study,experimental investigations on shear strength weakening of discontinuities with different joint wall material(DDJM)under cyclic loading were conducted by taking the interface between siltstone and mudstone in the Shaba slope of Yunnan Province,China as research objects.A total of 99 pairs of similar material samples of DDJM(81 pairs)and discontinuities with identical joint wall material(DIJM)(18 pairs)were fabricated by inserting plates,engraved with typical surface morphology obtained by performing three-dimensional laser scanning on natural DDJMs sampled from field,into mold boxes.Cyclic shear tests were conducted on these samples to study their shear strength changes with the cyclic number considering the effects of normal stress,joint surface morphology,shear displacement amplitude and shear rate.The results indicate that the shear stress vs.shear displacement curves under each shear cycle and the peak shear strength vs.cyclic number curves of the studied DDJMs are between those of DIJMs with siltstone and mudstone,while closer to those of DIJMs with mudstone.The peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number and the decrease rate varies from 6%to 55.9%for samples with varied surface morphology under different testing conditions.The normal stress,joint surface morphology,shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading,with the degree of influence being greater for larger normal stress,rougher surface morphology,larger shear displacement amplitude and faster shear rate. 展开更多
关键词 Discontinuities with different joint wall material(DDJM) Discontinuities with identical joint wall material(DIJM) Cyclic shear test Shear strength deterioration Joint surface morphology Shear displacement amplitude Shear rate Normal stress
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Prediction of ground surface displacement caused by grouting 被引量:3
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作者 郭风琪 刘晓潭 +1 位作者 童无期 单智 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3564-3570,共7页
Ground surface displacement caused by grouting was calculated with stochastic medium theory. Ground surface displacement was assumed to be caused by the cavity expansion of grouting, slurry seepage, and slurry contrac... Ground surface displacement caused by grouting was calculated with stochastic medium theory. Ground surface displacement was assumed to be caused by the cavity expansion of grouting, slurry seepage, and slurry contraction. A prediction method of ground surface displacement was developed. The reliability of the presented method was validated through a comparison between theoretical results and results from engineering practice. Results show that the present method is effective. The effect of parameters on uplift displacement was illustrated under different grouting conditions. Through analysis, it can be known that the ground surface uplift is mainly caused by osmosis of slurry and the primary influence angle of stratum β determines the influence range of surface uplift. Besides, the results show that ground surface uplift displacement decreases notably with increasing depth of the grouting cavity but it increases with increasing diffusion radius of grout and increasing grouting pressure. 展开更多
关键词 GROUTING ground surface displacement stochastic medium theory SEEPAGE slurry solidification shrinkage
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Assessment of the Design Displacement Values at Seismic Fault Crossings and of Their Excess Probability 被引量:1
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作者 STROM Alexander IVASCHENKO Alexey KOZHURIN Andrey 《Journal of Mountain Science》 SCIE CSCD 2011年第2期228-233,共6页
Line structures such as pipelines that cross active faults should be designed to retain leak-tightness if the design displacement (Ddesign) occurs. Principal approaches to the Ddesign and rupture kinematics assessment... Line structures such as pipelines that cross active faults should be designed to retain leak-tightness if the design displacement (Ddesign) occurs. Principal approaches to the Ddesign and rupture kinematics assessment are described. They are based on relationships between earthquake magnitude, rupture length and displacement, and on the detailed field data on a specific fault that crosses the pipeline route. Since the future offset at the crossing may exceed the design value, the probability of a displacement occurrence where the safety of the structure can not be ensured should be estimated. Assessment method on such event probability is described and exemplified through active fault studies carried out at several pipeline projects in Russia. 展开更多
关键词 Active Fault surface Rupture Design displacement Pipeline Sakhalin Island
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Shear sliding of rough-walled fracture surfaces under unloading normal stress 被引量:4
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作者 Qian Yin Chun Zhu +5 位作者 Jiangyu Wu Hai Pu Qi Wang Yuanchao Zhang Hongwen Jing Tianci Deng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第10期2658-2675,共18页
Through high-precision engraving,self-affine sandstone joint surfaces with various joint roughness coefficients(JRC=3.21e12.16)were replicated and the shear sliding tests under unloading normal stress were conducted r... Through high-precision engraving,self-affine sandstone joint surfaces with various joint roughness coefficients(JRC=3.21e12.16)were replicated and the shear sliding tests under unloading normal stress were conducted regarding various initial normal stresses(1e7 MPa)and numbers of shearing cycles(1 e5).The peak shear stress of fractures decreased with shear cycles due to progressively smooth surface morphologies,while increased with both JRC and initial normal stress and could be verified using the nonlinear Barton-Bandis failure criterion.The joint friction angle of fractures exponentially increased by 62.22%e64.87%with JRC while decreased by 22.1%e24.85%with shearing cycles.After unloading normal stress,the sliding initiation time of fractures increased with both JRC and initial normal stress due to more tortuous fracture morphologies and enhanced shearing resistance capacity.The surface resistance index(SRI)of fractures decreased by 4.35%e32.02%with increasing shearing cycles due to a more significant reduction of sliding initiation shear stress than that for sliding initiation normal stress,but increased by a factor of 0.41e1.64 with JRC.After sliding initiation,the shear displacement of fractures showed an increase in power function.By defining a sliding rate threshold of 5105 m/s,transition from“quasi-static”to“dynamic”sliding of fractures was identified,and the increase of sliding acceleration steepened with JRC while slowed down with shearing cycles.The normal displacement experienced a slight increase before shear sliding due to deformation recovery as the unloading stress was unloaded,and then enhanced shear dilation after sliding initiation due to climbing effects of surface asperities.Dilation was positively related to the shear sliding velocity of fractures.Wear characteristics of the fracture surfaces after shearing failure were evaluated using binary calculation,indicating an increasing shear area ratio by 45.24%e91.02%with normal stress. 展开更多
关键词 Unloading normal stress Rough fracture surface Shear sliding Normal displacement Shear wear characteristics
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Super-Resolution Displacement Spectroscopic Sensing over a Surface“Rainbow”
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作者 Lyu Zhou Nan Zhang +7 位作者 Chang Chieh Hsu Matthew Singer Xie Zeng Yizheng Li Haomin Song Josep Jornet Yun Wu Qiaoqiang Gan 《Engineering》 SCIE EI CAS 2022年第10期75-81,共7页
Subwavelength manipulation of light waves with high precision can enable new and exciting applications in spectroscopy,sensing,and medical imaging.For these applications,miniaturized spectrometers are desirable to ena... Subwavelength manipulation of light waves with high precision can enable new and exciting applications in spectroscopy,sensing,and medical imaging.For these applications,miniaturized spectrometers are desirable to enable the on-chip analysis of spectral information.In particular,for imaging-based spectroscopic sensing mechanisms,the key challenge is to determine the spatial-shift information accurately(i.e.,the spatial displacement introduced by wavelength shift or biological or chemical surface binding),which is similar to the challenge presented by super-resolution imaging.Here,we report a unique"rainbow"trapping metasurface for on-chip spectrometers and sensors.Combined with super-resolution image processing,the low-setting 4×optical microscope system resolves a displacement of the resonant position within 35 nm on the plasmonic rainbow trapping metasurface with a tiny area as small as0.002 mm2.This unique feature of the spatial manipulation of efficiently coupled rainbow plasmonic resonances reveals a new platform for miniaturized on-chip spectroscopic analysis with a spectral resolution of 0.032 nm in wavelength shift.Using this low-setting 4×microscope imaging system,we demonstrate a biosensing resolution of 1.92×109exosomes per milliliter for A549-derived exosomes and distinguish between patient samples and healthy controls using exosomal epidermal growth factor receptor(EGFR)expression values,thereby demonstrating a new on-chip sensing system for personalized accurate bio/chemical sensing applications. 展开更多
关键词 Rainbow trapping Metasurface surface plasmon polaritons Super-resolution displacement On-chip biosensing
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纳米生物质体系性能评价及驱油特性实验研究
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作者 吴向阳 李建勋 +2 位作者 李刚 梅艳 金戈 《化学工程师》 CAS 2024年第11期50-53,49,共5页
本文以玉米秸秆与纳米硅为原料,制备了改性纳米生物质,并评价了其在不同条件下的表面活性及界面张力。通过调整纳米生物质浓度(0.1%~1.0%)、注入速度(0.1~1.0mL·min^(-1))及注入体积(100~1000mL),优化体系的驱油参数。结果显示,纳... 本文以玉米秸秆与纳米硅为原料,制备了改性纳米生物质,并评价了其在不同条件下的表面活性及界面张力。通过调整纳米生物质浓度(0.1%~1.0%)、注入速度(0.1~1.0mL·min^(-1))及注入体积(100~1000mL),优化体系的驱油参数。结果显示,纳米生物质浓度为0.8%、注入速度为0.6mL·min^(-1)、注入体积为600mL时,体系表现出最佳的驱油效率。此外,实验室结果在典型油田的现场应用中得到验证,应用优化后的体系参数,油田的日产油率从100桶提升至140桶,增幅达40%。由此可见,纳米生物质体系能够提高油田驱油效率,研究成果有助于指导油田开发中生物质材料的应用。 展开更多
关键词 纳米生物质体系 表面张力 界面张力 驱油效率
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抢险车对92m跨度复合材料桁架桥动态响应的影响
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作者 孙泽阳 刘阳 +2 位作者 杨俊锋 吴必涛 赵启林 《江苏大学学报(自然科学版)》 CAS 北大核心 2024年第3期346-353,共8页
为研究大跨径桁架式纤维增强复合材料(FRP)应急抢修桥梁成桥后的动力性能,基于导梁推送施工92 m跨度的FRP桁架桥模型,编制FRP桁架桥的车桥耦合算法,研究抢险车辆的车速、质量及路面不平顺对FRP桁架桥的跨中竖向位移、竖向加速度和关键... 为研究大跨径桁架式纤维增强复合材料(FRP)应急抢修桥梁成桥后的动力性能,基于导梁推送施工92 m跨度的FRP桁架桥模型,编制FRP桁架桥的车桥耦合算法,研究抢险车辆的车速、质量及路面不平顺对FRP桁架桥的跨中竖向位移、竖向加速度和关键杆件轴向应力等指标的影响.结果表明:路面越不平顺,车辆对桥梁结构的冲击作用越大,且路面等级对竖向位移的影响大于对关键杆件轴向应力的影响;车速为20~50 km/h时,车速变化对冲击系数影响较小,但车速超过50 km/h时,车速的影响逐渐增大;车辆质量对桥梁各项指标动力响应的峰值曲线呈线性增大趋势.当车辆质量为2.80×10^(4)kg,车速30 km/h时,最大跨中竖向位移为167 mm,未超过抢修桥梁位移限值(L/120),表明该桥梁的设计可以满足抢险的通行要求. 展开更多
关键词 纤维增强复合材料桁架桥 车桥耦合 位移接触法 动态响应 路面不平顺
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基于CNN-BiLSTM-Attention的三峡库区滑坡地表位移预测研究
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作者 陈欢 冯晓亮 +4 位作者 刘一民 赵晗 刘洋 郭浪 张军 《沉积与特提斯地质》 CAS CSCD 北大核心 2024年第3期572-581,共10页
地表位移预测在滑坡监测预警中具有重要意义,建立稳定可靠的滑坡位移预测模型是关键。本文基于卷积神经网络和注意力机制的滑坡位移预测方法,并以三峡库区黄泥巴蹬坎滑坡为例进行了验证。本文综合分析了该滑坡长达8年的降雨量、库水位... 地表位移预测在滑坡监测预警中具有重要意义,建立稳定可靠的滑坡位移预测模型是关键。本文基于卷积神经网络和注意力机制的滑坡位移预测方法,并以三峡库区黄泥巴蹬坎滑坡为例进行了验证。本文综合分析了该滑坡长达8年的降雨量、库水位和地表位移等监测数据,建立了结合卷积神经网络(convolutional neural network,CNN)、双向长短期记忆(bidirectional long short-term memory,BiLSTM)网络和注意力机制(attention)的CNN-BiLSTM-Attention深度学习组合预测模型,采用了适应性学习率和正则化技术进行模型训练,提高了模型的泛化能力同时避免过拟合,并与传统LSTM模型进行对比验证。结果表明:相较于传统的机器学习和神经网络方法,该模型在滑坡位移预测精度上取得了显著提升,预测模型拟合优度(R^(2))达0.989,平均绝对百分比误差(MAPE)仅为0.059。 展开更多
关键词 滑坡监测 地表位移 注意力机制 预测模型 三峡库区
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基于平面和深部位移联合监测的滑坡精准勘察
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作者 李伟 王哲威 《路基工程》 2024年第3期207-212,共6页
基于某高速公路高边坡滑坡工程,在地质调查、钻探、原位测试等基础上,引入基于平面和深部位移联合监测模式进行精准勘察。通过平面位移监测确定滑坡周界和滑动方向;通过深部测斜确定滑面位置;通过6孔钻探补充查明空间结构特征。根据深... 基于某高速公路高边坡滑坡工程,在地质调查、钻探、原位测试等基础上,引入基于平面和深部位移联合监测模式进行精准勘察。通过平面位移监测确定滑坡周界和滑动方向;通过深部测斜确定滑面位置;通过6孔钻探补充查明空间结构特征。根据深部监测指导钻孔取样获取滑带土指标,检算天然和饱和工况下的稳定性系数分别为1.01、0.98;分析监测数据,滑坡滑动规律为连续降雨期间滑动速率增大,停止施工后滑动速率下降,变形速率从后部向前部逐渐减小,属推移式滑坡;提出清方+重力式罩面的综合整治方案。 展开更多
关键词 滑坡 勘察 平面位移监测 竖向位移监测 滑坡周界 滑动面
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基于机器视觉的闸坝表面位移非接触式监测方法
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作者 陈波 何梦佳 +1 位作者 刘伟琪 马聪 《水利学报》 EI CSCD 北大核心 2024年第9期1110-1122,共13页
针对闸坝表面位移常规监测方法劳动密度高、监测频次低,且难以实现长期稳定监测等问题,提出一种融合时空特征的闸坝表面位移非接触式智能监测方法。该方法采用人工靶标作为标志物,以摄像机为采集设备,通过无线传输图像信息,利用加权分... 针对闸坝表面位移常规监测方法劳动密度高、监测频次低,且难以实现长期稳定监测等问题,提出一种融合时空特征的闸坝表面位移非接触式智能监测方法。该方法采用人工靶标作为标志物,以摄像机为采集设备,通过无线传输图像信息,利用加权分布的自适应伽马修正(AGCWD)与边缘感知因子改进的加权引导滤波(WGIF)增强低照度图像的特征表达能力,通过计算机搭载基于贝叶斯框架的时空上下文信息(STC)算法深度挖掘靶标图像上下文时空信息,进一步地,引入曲面拟合获取靶标的亚像素级位移时程信息,实现闸坝水平和垂直双向表面位移的亚像素级非接触式监测。实验室与现场试验结果表明,不同实验场景下位移监测数据与校验数据高度一致,误差小于0.05 mm;相比于图像优化处理方法,基于AGCWD与WGIF的图像优化处理方法的峰值信噪比提升2.70%,信息熵增加4.91%,标准差降低2.63%;相比于目标追踪算法,基于曲面拟合的STC目标追踪算法的现场监测数据较同类目标追踪算法精度提升48%,可为闸坝表面位移监测提供高精度的解决方案。 展开更多
关键词 闸坝 表面位移监测 图像序列时空特征 数字图像优化 亚像素级目标追踪
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基于2D-DIC的轴体扭矩测量方法
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作者 袁治未 陈爱军 +2 位作者 林杰俊 胡佳成 蔡晋辉 《现代电子技术》 北大核心 2024年第21期165-170,共6页
针对传统二维数字图像相关法易受离面位移影响,难以用于测量扭矩这一现状,文中在现有二维数字图像相关法的基础上,提出基于曲面展开和位移量预测的轴体扭矩测量方法。采用曲面展开法将二维轴体图像与轴体物理结构进行结合,获取轴体三维... 针对传统二维数字图像相关法易受离面位移影响,难以用于测量扭矩这一现状,文中在现有二维数字图像相关法的基础上,提出基于曲面展开和位移量预测的轴体扭矩测量方法。采用曲面展开法将二维轴体图像与轴体物理结构进行结合,获取轴体三维曲面信息,有效补偿了轴体扭转位移计算结果,并利用位移量预测法减少了参考子区与变形子区相对位移的计算量。进行了曲面展开法补偿扭转位移前后的对比实验,传统数字图像相关法与位移量预测法的对比实验和不同直径轴体扭矩测量实验。实验结果表明:加入曲面展开法后,扭矩测量结果的绝对误差最高减小了0.21 N·m;位移量预测法相对传统方法计算结果相近,但计算速度最高提升了31.6%;不同直径轴体扭矩测量结果的相对误差在±4.35%以内,具有较好的稳定性和准确性。 展开更多
关键词 二维数字图像相关法 轴体 扭矩 离面位移 曲面展开法 位移量预测法
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驱油流体吸附抑制剂的合成与评价
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作者 赵帅 田雨 +3 位作者 吴澳回 安锋涛 杨林 师永民 《石油与天然气化工》 CAS CSCD 北大核心 2024年第1期98-103,共6页
目的在化学驱的实施过程中,地层对驱油剂的吸附滞留是表面活性剂进入地层后含量损失的一种主要原因,为了减少驱油流体在地层的损耗成本而展开对驱油液体吸附抑制剂的研究。方法以二氰二胺(DCD)、1-十八胺盐酸盐(OHC)为原料,基于亲核加... 目的在化学驱的实施过程中,地层对驱油剂的吸附滞留是表面活性剂进入地层后含量损失的一种主要原因,为了减少驱油流体在地层的损耗成本而展开对驱油液体吸附抑制剂的研究。方法以二氰二胺(DCD)、1-十八胺盐酸盐(OHC)为原料,基于亲核加成的原理采用熔融法在150℃下合成了一种针对驱油流体的吸附抑制剂OHCB,该表面活性剂同时具备强疏水基、强极性原子和阳离子基团,因此具有较强的占据黏土矿物表面吸附位点的能力。对其进行了红外吸收、紫外吸收、元素分析、质谱等结构表征,采用静态吸附法研究了其作为添加剂的最佳配比,并验证在最佳配比下对驱油剂AEO7的吸附抑制效果,以及该体系相较AEO7单一体系的静态洗油效率、乳化性及润湿性的变化。结果OHCB抑制驱油剂AEO7在黏土矿物表面的吸附效果较好,在驱油剂与吸附抑制剂质量比为5∶1的情况下,抑制效果可达27%以上。结论OHCB不仅具有较好的吸附抑制效果,且其加入使AEO7的静态洗油效率提升至27.3%、γc m c降至27.1 mV/m,CMC降至38 mg/L、油-水界面张力降至0.5 mV/m以下,对体系性能起到了协同增效的作用,并且相较于需要预吸附的牺牲剂,其使用更为便捷。 展开更多
关键词 吸附抑制 驱油 静态洗油效率 表面张力 界面张力
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光通信用激光器及光电二极管质子位移损伤效应研究
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作者 玛丽娅·黑尼 李豫东 +2 位作者 王信 何承发 郭旗 《现代应用物理》 2024年第4期96-102,115,共8页
激光器、探测器等光通信器件对空间辐射环境中高能粒子引入的位移损伤敏感,且随时间累积不可恢复。针对光通信用垂直腔面发射激光器和光电二极管开展了质子辐照试验,并对辐照前后器件的光功率-电流-电压曲线、阈值电流、低频噪声等参数... 激光器、探测器等光通信器件对空间辐射环境中高能粒子引入的位移损伤敏感,且随时间累积不可恢复。针对光通信用垂直腔面发射激光器和光电二极管开展了质子辐照试验,并对辐照前后器件的光功率-电流-电压曲线、阈值电流、低频噪声等参数进行了测试分析。研究结果表明:由于质子辐照后,载流子被辐射感生缺陷形成的非辐射复合中心捕获,降低了少数载流子的寿命,复合产生的光子数量减少,因此850 nm垂直腔面发射激光器在质子辐照后光输出功率、外量子效率随注量的增加而降低;InGaAs光电二极管暗电流和噪声密度谱增加。 展开更多
关键词 位移损伤 垂直腔面发射激光器 InGaAs光电二极管 阈值电流 暗电流
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软土地区超深基坑设计优化分析
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作者 王淞 刘永超 +1 位作者 张建新 宋昭煌 《天津城建大学学报》 CAS 2024年第1期1-8,共8页
天津一中心医院新址基坑工程位于天津西青软土区,具有超大、超深的特点.开挖后由于工期因素,需要对原支护方案进行优化调整,采用启明星软件和Plaxis 2D有限元模拟对优化前后的典型剖面进行对比,并将开挖实测数据与模拟值进行综合对比分... 天津一中心医院新址基坑工程位于天津西青软土区,具有超大、超深的特点.开挖后由于工期因素,需要对原支护方案进行优化调整,采用启明星软件和Plaxis 2D有限元模拟对优化前后的典型剖面进行对比,并将开挖实测数据与模拟值进行综合对比分析.结果表明:在支护桩已经完成的条件下,优化后方案技术可行,安全可靠,支护桩的弯矩和截面变化处于合理范围内.同时,在北侧和西南角设立两座出土栈桥,有利于提高开挖效率,缩短工期,降低成本,部分区域支护桩最大侧向水平位移地表沉降值比原方案有所增加,变形依旧控制在合理范围内,可对类似的超大深基坑工程方案优化提供借鉴. 展开更多
关键词 方案优化 支护桩侧移 地表沉降 数值模拟
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