期刊文献+
任意字段
题名或关键词
题名
关键词
摘要
作者
第一作者
机构
刊名
分类号
参考文献
作者简介
基金资助
栏目信息
共找到511篇文章
< 1 2 … 26 >
每页显示 20 50 100
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
显示方式：
Influence of groundwater drawdown on excavation responses e A case history in Bukit Timah granitic residual soils 认领 引用 被引量：22
1
作者 Wengang Zhang Wei Wang +3 位作者 Dong Zhou Runhong Zhang A.T.C. Goh Zhongjie Hou 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2018年第5期856-864,共9页
Performances of a braced cut-and-cover excavation system for mass rapid transit （MRT） stations of the Downtown Line Stage 2 in Singapore are presented. The excavation was carried out in the Bukit Timah granitic （BT... Performances of a braced cut-and-cover excavation system for mass rapid transit （MRT） stations of the Downtown Line Stage 2 in Singapore are presented. The excavation was carried out in the Bukit Timah granitic （BTG） residual soils and characterized by significant groundwater drawdown, due to dewatering work in complex site conditions, insufficient effective waterproof measures and more permeable soils. A two-dimensional numerical model was developed for back analysis of retaining wall movement and ground surface settlement. Comparisons of these measured excavation responses with the calculated performances were carried out, upon which the numerical simulation procedures were calibrated. In addition, the influences of groundwater drawdown on the wall deflection and ground surface settlement were numerically investigated and summarized. The performances were also compared with some commonly used empirical charts, and the results indicated that these charts are less applicable for cases with significant groundwater drawdowns. It is expected that these general behaviors will provide useful references and insights for future projects involving excavation in BTG residual soils under significant groundwater drawdowns. 展开更多
关键词 Braced excavation Bukit Timah granitic （BTG） residual soil Wall deflection Groundwater drawdown Empirical charts
暂未订购 下载PDF
Drawdown mechanism of light particles in baffled stirred tank for the KR desulphurization process 认领 引用 被引量：12
2
作者 Meng Li Yangbo Tan +2 位作者 Jianglong Sun De Xie Zeng Liu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第2期247-256,共10页
To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds(Njd) of floati... To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds(Njd) of floating particles in transformative Kanbara Reactor(KR) are measured in one and four baffled stirred tanks experimentally. Then numerical simulations with standard k-ε model coupled with volume of fluid model(VOF) and discrete phase model(DPM) are conducted to analyze the flow field at the just drawdown speed Njd. The torques on the impeller obtained from experiments and simulations agree well with each other, which indicates the validity of our numerical simulations. Based on the simulations, three main drawdown mechanisms for floating particles, the axial circulation, turbulent fluctuation and largescale eddies, are analyzed. It's found that the axial circulation dominates the drawdown process at small submergence(S = 1/4 T and 1/3 T) and the large-scale eddies play a major role at large submergence(S = 2/3 T and 3/4 T). Besides, the turbulent fluctuation affects the drawdown process significantly for up pumping mode at small submergence(S = 1/4 T and 1/3 T) and for down pumping mode at large submergence(S = 2/3 T and 3/4 T). This paper helps to provide a more comprehensive understanding of the KR desulphurizer drawdown process in the baffled stirred tank. 展开更多
关键词 Light particles Drawdown mechanism Baffled stirred tank Submergence Numerical simulations KR impeller
暂未订购 下载PDF
Centrifuge model tests on pile-reinforced slopes subjected to drawdown 认领 引用 被引量：10
3
作者 Sujia Liu Fangyue Luo Ga Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2020年第6期1290-1300,共11页
Piles are generally an effective way to reduce the risk of slope failure.However,previous approaches for slope stability analysis did not consider the effect of the piles coupled with the decrease of the water level(d... Piles are generally an effective way to reduce the risk of slope failure.However,previous approaches for slope stability analysis did not consider the effect of the piles coupled with the decrease of the water level(drawdown).In this study,a series of centrifuge model tests was performed to understand the deformation and failure characteristics of slopes reinforced with various pile layouts.In the centrifuge model tests,the pile-reinforced slopes exhibited two typical failure modes under drawdown conditions:across-pile failure and through-pile failure.In the through-pile slope failure,a discontinuous slip surface was observed,implying that the assumption of the slip surface in previous stability analysis methods was unreasonable.The test results showed that drawdown led to instability of the piles in cohesive soil,as the saturated cohesive soil failed to provide sufficient constraint for piles.The slope exhibited progressive failure,from top to bottom,during drawdown.The deformation of the piles was reduced by increasing the embedment depth and row number of piles.In addition,the deformation of soils outside the piles was influenced by the piles and showed a similar distribution shape as the piles,and the similarity degree weakened as the distance from the piles increased.This study also found that the failure mechanism of unreinforced and pile-reinforced slopes induced by drawdown could be described by coupling between the deformation localization and local failure,and it revealed that pile-reinforced slopes could reduce slope deformation localization during drawdown. 展开更多
关键词 Slope Pile Drawdown Failure Reinforcement Centrifuge model test
暂未订购 下载PDF
Stability analysis for nonhomogeneous slopes subjected to water drawdown 认领 引用 被引量：3
4
作者 SUN Zhi-bin SHU Xing Daniel DIAS 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第7期1719-1734,共16页
Comparing with the homogeneous slope,the nonhomogeneous slope has more significance in practice.The main purpose of the present study is to provide a preliminary idea that how the nonhomogeneity influences the stabili... Comparing with the homogeneous slope,the nonhomogeneous slope has more significance in practice.The main purpose of the present study is to provide a preliminary idea that how the nonhomogeneity influences the stability of slopes under four different water drawdown regimes.Two typical categories of nonhomogeneity,identified as layered profile and strength increasing with depth profile,are included in the paper,and a nonhomogeneity coefficient is defined to quantify the degree of soil properties nonhomogeneity.With a modified discretization technique,the safety factors of nonhomogeneous slopes are calculated.On this basis,the variation of safety factor with the nonhomogeneity coefficient of friction angle and the water table level are investigated.In the present example,safety factor correlates linearly with friction angle nonhomogeneity coefficient from a whole view and the influences of the water table level on safety factor is basically similar with that in homogeneous condition. 展开更多
关键词 upper bound discretization technique non-homogeneous slope water drawdown
暂未订购 下载PDF
Numerical analysis of rapid drawdown: Applications in real cases 认领 引用 被引量：4
5
作者 Eduardo E. Alonso Nuria M. Pinyol 《Water Science and Engineering》 EI CAS CSCD 2016年第3期175-182,共8页
In this study, rapid drawdown scenarios were analyzed by means of numerical examples as well as modeling of real cases with in situ measurements. The aim of the study was to evaluate different approaches available for... In this study, rapid drawdown scenarios were analyzed by means of numerical examples as well as modeling of real cases with in situ measurements. The aim of the study was to evaluate different approaches available for calculating pore water pressure distributions during and after a drawdown. To do that, a single slope subjected to a drawdown was first analyzed under different calculation alternatives, and numerical results were discussed. Simple methods, such as undrained analysis and pure flow analysis, implicitly assuming a rigid soil skeleton, lead to significant errors in pore water pressure distributions when compared with coupled flow-deformation analysis. A similar analysis was performed for the upstream slope of the Glen Shira Dam, Scotland, and numerical results were compared with field measurements during a controlled drawdown. Field records indicate that classical undrained calculations are conservative but unrealistic. Then, a recent case of a major landslide triggered by a rapid drawdown in a reservoir was interpreted. A key aspect of the case was the correct characterization of permeability of a representative soil profile. This was achieved by combining laboratory test results and a back analysis of pore water pressure time records during a period of reservoir water level fluctuations. The results highlight the difficulty of predicting whether the pore water pressure is overestimated or underestimated when using simplified approaches, and it is concluded that predicting the pore water pressure distribution in a slope after a rapid drawdown requires a coupled flow-deformation analysis in saturated and unsaturated porous media. 展开更多
关键词 Hydro-mechanical coupling Coupled flow-deformation analysis Numerical analysis Drawdown Landslide Pore water pressure
暂未订购 下载PDF
Numerical Study on Groundwater Drawdown and Deformation Responses of Multi-Layer Strata to Pumping in a Confined Aquifer 认领 引用 被引量：2
6
作者 WANG Dafa LI Mingguang +2 位作者 CHEN Jinjian XIA Xiaohe ZHANG Yangqing 《Journal of Shanghai Jiaotong university(Science)》 EI 2019年第3期287-293,共7页
Pumping artesian water from porous media inevitably reduces the groundwater head and promotes soil consolidation,which may result in regional land subsidence.In this study,a fluid-mechanical coupled numerical model is... Pumping artesian water from porous media inevitably reduces the groundwater head and promotes soil consolidation,which may result in regional land subsidence.In this study,a fluid-mechanical coupled numerical model is developed to investigate the dewatering-induced groundwater drawdown and deformation responses for multi-layer strata.The relation bet ween the stra tum deformation and groundwater drawdown is discussed.The results show that the pumping process can be divided into four st ages.The development of vertical deformation is inconsistent with the change of the pore pressure for the strata except for the confined aquifer at the early stage of pumping.The st rata expand while the pore pressures reduce.This inconsistency may be due to the large unloading in the confined aquifer at the early stage of pumping.Soil arch comes into being owing to the constraint of the surrounding soils when the large unloading occurs in the confined aquifer;this can reduce the stratum compression and cause the expansion of the layers.It can be concluded that as the pumping continues,the decrease of the pore pressure dominates the vertical deformation and results in the soil compression in all strata. 展开更多
关键词 pumping multi-layer strata numerical analysis groundwater drawdown stratum deformation
暂未订购 下载PDF
Calculation of Motor-pumped Well’s Drawdown in Land Consolidation 认领 引用
7
作者 樊鹏 刘雁南 《Agricultural Science & Technology》 CAS 2013年第6期934-936,共3页
[Objective] The aim was to explore the measurement methods of drawdown of motor-pumped well in land consolidation. [Method] Based on pumping information, the relation curve of drawdown and pumped volume was drawn and ... [Objective] The aim was to explore the measurement methods of drawdown of motor-pumped well in land consolidation. [Method] Based on pumping information, the relation curve of drawdown and pumped volume was drawn and the empirical formula was concluded, with examples. [Result] The type of drawdown （h） and flow volume （Q） includes linear type, parabolic type, exponential curve and logarithmic curve. Graphical method and calculus of differences are available for determining the type of curve. [Conclusion] The empirical formula based on pumping test reflects relation between drawdown and pumping volume, which is simple and effective. 展开更多
关键词 Land consolidation Drawdown Empirical formula
暂未订购 下载PDF
Experimental and Numerical Assessment of the Influence of Bottomhole Pressure Drawdown on Terrigenous Reservoir Permeability and Well Productivity 认领 引用 被引量：2
8
作者 Sergey Popov Sergey Chernyshov Evgeniy Gladkikh 《Fluid Dynamics & Materials Processing》 EI 2023年第3期619-634,共16页
During oil and gas fields development,a decrease in reservoir and bottomhole pressure has often a detrimental effect on reservoir properties,especially permeability.This study presents the results of laboratory tests ... During oil and gas fields development,a decrease in reservoir and bottomhole pressure has often a detrimental effect on reservoir properties,especially permeability.This study presents the results of laboratory tests conducted to determine the response of terrigenous reservoir core-sample permeability to changes in the effective stresses and a decrease in the reservoir pressure.The considered samples were exposed for a long time to a constant high effective stress for a more reliable assessment of the viscoplastic deformations.According to these experiments,the decrease of the core samples permeability may reach 21%with a decrease in pressure by 9.5 MPa from the initial reservoir conditions.Numerical simulations have been also conducted.These have been based on the finite element modeling of the near-wellbore zone of the terrigenous reservoir using poroelasticity relations.The simulation results show a limited decrease in reservoir permeability in the near-wellbore zone(by 17%,which can lead to a decrease in the well productivity by 13%). 展开更多
关键词 Terrigenous reservoir permeability core sample reservoir pressure bottomhole pressure drawdown effective stress well productivity
暂未订购 下载PDF
模糊厌恶下最小Drawdown概率的最优投资再保险策略 认领 引用 被引量：1
9
作者 赵玉莹 温玉珍 《数学物理学报（A辑）》 CSCD 北大核心 2021年第4期1147-1165,共19页
该文考虑了模糊厌恶下保险公司的最优投资和再保险问题,得到了保险市场和金融市场均存在模糊厌恶时,保险公司盈余的最小drawdown概率及其最优鲁棒投资和再保险策略的解析解.通过数值分析得出一些重要参数对值函数的影响.
关键词 模糊厌恶 drawdown概率 最优鲁棒投资再保险策略 扭曲漂移
暂未订购 下载PDF
Factors Influencing the Iterative Accuracy of Ground Water Level in Forecasting the Water Burst of Deep Drawdown Mines 认领 引用
10
作者 李铎 杨小荟 +1 位作者 武强 张志忠 《Journal of China University of Mining and Technology》 2002年第1期81-85,共5页
The purpose of this paper is to discuss the influential factors of iteration accuracy when we use iteration to determine the numerical model for predicting water yield of deep drawdown mines and calculating the ground... The purpose of this paper is to discuss the influential factors of iteration accuracy when we use iteration to determine the numerical model for predicting water yield of deep drawdown mines and calculating the groundwater level. The relationship among the calculation error of groundwater level, the pumping rate, the limit of iteration convergence error, the calculation time, and the aquifer parameters were discussed by using an ideal model. Finally, the water yield of Dianzi iron mine was predicted using the testified numerical model. It is indicated that the calculation error of groundwater level is related to the limit of iteration convergence error, the calculation time and the aquifer parameters, but not to the pumping rate and the variation of groundwater level. 展开更多
关键词 deep drawdown water yield groundwater level iteration error limit
暂未订购 下载PDF
Approach to quantification drawdown of groundwater wells:a case study from Sana'a City,Yemen 认领 引用
11
作者 Abdulhakim G. H. A1-KHOLID SUN Youhong +1 位作者 Aref M. O. AL-JABALI SUN Zhifeng 《Global Geology》 2010年第3期155-158,共4页
Although research on a field investigation about quantification drawdown of ground water wells has hitherto been conducted with emphasis on Sana'a basin which is 3 200 km2 in area characterized by general hazard i... Although research on a field investigation about quantification drawdown of ground water wells has hitherto been conducted with emphasis on Sana'a basin which is 3 200 km2 in area characterized by general hazard in quantity and quality of water,there exist uncertainties about the size of the hazardous annual decline in the level of underground water. So the authors are trying to assess reliable hazard data on the depth of ground-water which were obtained by measuring static water level. The data set are twenty six wells from 9 regions which were selected to represent Sana'a basin and collected during the course of the 20 months groundwater monitoring survey from January 2008 to January 2009. The results show that the average drawdown during 20 months to be 3.22 m with an average 0.16 m per month and 2 m per year. 展开更多
关键词 quantifications Sanaa basin drawdown groundwater wells average
暂未订购 下载PDF
Ground Subsidence Following Groundwater Drawdown by Excavating of 500 m Deep Investigation Shafts in Granite Body in Mizunami, Central Japan in 2004-2012 认领 引用
12
作者 Fumiaki Kimata Yasuhiro Asai +3 位作者 Ryo Honda Toshiyuki Tanaka Hiroshi Ishii Rikio Miyajima 《Engineering（科研）》 2015年第7期424-433,共10页
Two 500 m deep investigation shafts were excavating in the granite body in Mizunami, central Japan by JAEA (Japan Nuclear Cycle Development Institute) in 2004-2012. Groundwater with volume of 700 m3 was generally pump... Two 500 m deep investigation shafts were excavating in the granite body in Mizunami, central Japan by JAEA (Japan Nuclear Cycle Development Institute) in 2004-2012. Groundwater with volume of 700 m3 was generally pumping a day to prevent the shafts from submerging in 2012 following the excavating. As a result of pumping the groundwater, the ground water level lowered to 60 m in the borehole with the distance of 200 m from the excavating shafts in 2012. Leveling network extending 2 km × 2 km around the shafts was established to detect the vertical deformation around the shafts in 2004, and precise leveling was done every year. An 18 mm ground subsidence was detected in the benchmark close to the shafts for 8 years in 2004-2012, and time series of subsidence at benchmark was consistent with the groundwater drawdown. The groundwater drawdown and ground subsidence were caused by the pumping ground water in excavating shafts. 展开更多
关键词 Ground Subsidences Groundwater Drawdown 500 m Deep Excavation Shaft Precise Leveling Groundwater Drainage
暂未订购 下载PDF
Performance of braced excavation in residual soil with groundwater drawdown 认领 引用 被引量：29
13
作者 W.G.Zhang A.T.C.Goh +3 位作者 K.H.Goh O.Y.S.Chew D.Zhou Runhong Zhang 《Underground Space》 SCIE EI 2018年第2期150-165,共16页
In densely built-up Singapore,relatively stiffsecant-bored piles and diaphragm walls are commonly used in cut-and-cover works to minimize the impact of ground movement on the adjacent structures and utilities.For exca... In densely built-up Singapore,relatively stiffsecant-bored piles and diaphragm walls are commonly used in cut-and-cover works to minimize the impact of ground movement on the adjacent structures and utilities.For excavations in stiffresidual soil deposits,the asso-ciated wall deflections and ground settlements are generally smaller than for excavations in soft soil deposits.However,if the residual soil permeability is high and the underlying rock is highlyfissured or fractured,substantial groundwater drawdown and associated seepage-induced settlement may occur.In this study,the excavation performance of four sites in residual soil deposits with maximum excavation depths between 20 and 24 m is presented.The maximum wall deflections were found to be relatively small compared to the significantly larger maximum ground settlements,owing to the extensive lowering of the groundwater table.In this paper,details of the subsurface conditions,excavation support system,field instrumentation,and observed excavation responses are presented,with particular focus on the large groundwater drawdown and associated ground settlement.Specific issues encountered during the excavation,as well as the effectiveness of various groundwater control measures,are discussed.The case studies will provide useful references and insights for future projects involving braced excavations in residual soil. 展开更多
关键词 Residual soil Braced excavation Wall deflection Ground settlements Groundwater drawdown Strut force
Effects of surface vortex on the drawdown and dispersion of floating particles in stirred tanks 认领 引用 被引量：2
14
作者 Wentao Xu Yangbo Tan +3 位作者 Meng Li Jianglong Sun De Xie Zeng Liu 《Particuology》 SCIE EI CAS CSCD 2020年第2期159-168,共10页
The effects of surface vortex on the drawdown and dispersion of floating particles in stirred tanks were investigated.Particle distribution and power consumption were analyzed by experiments and numerical simulations ... The effects of surface vortex on the drawdown and dispersion of floating particles in stirred tanks were investigated.Particle distribution and power consumption were analyzed by experiments and numerical simulations in both baffled and unbaffled tanks agitated by a Rushton impeller.In unbaffled tanks,a non-aggregation rule was applied and the average dispersion index was found to serve as a reasonable prediction of the full drawdown of floating particles.The critical impeller speeds in an unbaffled tank were higher than those in a tank with vertical baffles.At each immersion depth in a baffled tank,particles distributed more uniformly and more power was consumed.Comparison of snapshots of the baffled and unbaffled tanks shows that the surface vortex increases the drawdown speed while it decreases the particle distribution uniformity and power consumption.Therefore,the use of baffles to suppress the surface vortex provides for a more uniform particle distribution in stirred tanks. 展开更多
关键词 Stirred tank Surface vortex Solids drawdown Complete dispersion
基于试采数据的页岩气井生产制度优化方法——以蜀南地区L203井区为例 认领 引用
15
作者 杜强 王维一 +7 位作者 杨思雨 吴洪波 罗迪 赵珑昊 陈家庆 岳文翰 王林 余杨康 《钻采工艺》 CAS 北大核心 2026年第4期106-113,共8页
控压生产制度可以影响页岩气井EUR,然而现场对影响机理却认识尚不全面,缺乏基于页岩气单井地质、工程、排采特征的定量生产制度。文章对优化生产制度而提高EUR的增产机理进行了研究,并在此基础上提出了各生产阶段的生产制度优化方法。... 控压生产制度可以影响页岩气井EUR,然而现场对影响机理却认识尚不全面,缺乏基于页岩气单井地质、工程、排采特征的定量生产制度。文章对优化生产制度而提高EUR的增产机理进行了研究,并在此基础上提出了各生产阶段的生产制度优化方法。在单相压裂液返排阶段,采用逐级放大油嘴试采,根据产水量与压力响应优选油嘴尺寸。在控压生产阶段,先以递增压降速度试采,再根据页岩气井地质与工程参数建立解析模型,拟合不同压降速度下的生产历史数据,并计算EUR,最后绘制EUR与压降速度的关系曲线以确定合理压降速度。蜀南地区L203H10-3井实例应用表明,该井单相压裂液返排阶段的最佳油嘴尺寸为4 mm;控压生产阶段最大降压速度应小于0.5 MPa/d。该方法结合了页岩气井的地质、工程、排采等参数优化生产制度,理论基础可靠,可为提高页岩气井的EUR提供技术支撑。 展开更多
关键词 页岩气 蜀南地区 生产制度 压降速度 固体颗粒
暂未订购 下载PDF
考虑渗透各向异性的动水压力型滑坡变形响应规律 认领 引用
16
作者 刘艺梁 朱前 +5 位作者 李永奕 左清军 樊西丰 宋琨 申高伟 汤罗圣 《安全与环境工程》 CAS CSCD 北大核心 2026年第1期56-68,共13页
动水压力型滑坡是三峡水库运行过程中重要的地质灾害类型,其坡体结构松散、孔隙比大、渗透性强,滑体渗透性在不同方向上呈现明显差异。为研究渗透各向异性对动水压力型滑坡变形响应规律的影响,以三峡库区白家包滑坡为研究对象,采用渗透... 动水压力型滑坡是三峡水库运行过程中重要的地质灾害类型,其坡体结构松散、孔隙比大、渗透性强,滑体渗透性在不同方向上呈现明显差异。为研究渗透各向异性对动水压力型滑坡变形响应规律的影响,以三峡库区白家包滑坡为研究对象,采用渗透系数比值kx/ky表征渗透各向异性,系统分析了不同滑体渗透系数比值kx/ky和库水位下降速率v作用下滑坡地表位移和变形滞后时间的变化规律。研究结果表明:①随渗透系数比值kx/ky增大,滑坡前部浸润线抬升,坡体内外水头差同步增大,指向坡外的动水压力相应增强。②当库水位下降速率保持不变时,滑体渗透系数比值越大,滑坡地表位移和变形滞后时间越大;当0.110时,地表位移增量和变形滞后时间基本保持不变。③滑坡前缘变形对渗透各向异性和库水位下降速率的敏感性影响程度明显高于中后缘;当库水位下降速率保持不变时,滑坡前部监测点的地表位移增量大于中后部监测点地表位移增量。研究成果对动水压力型滑坡变形分析和监测预警具有重要的应用价值。 展开更多
关键词 动水压力型滑坡 各向异性 渗透系数 库水位下降 地表位移 滞后时间
暂未订购 下载PDF
三峡库区巫峡段岩溶岸坡水下岩腔识别与发育特征分析 认领 引用
17
作者 龚诚 管振德 +2 位作者 蒙彦 杨勇 黄海 《中国岩溶》 CAS CSCD 北大核心 2026年第1期167-178,共12页
三峡库区长期性水位波动引起的岩溶岸坡溶蚀劣化是危岩崩塌灾害的重要诱因,查明涉水危岩带基底岩腔发育特征是重大高位崩塌灾害隐患识别的技术基础。文章选取三峡库区巫峡段为研究区域,采用多波束测深系统结合三维声呐点云数据融合分析... 三峡库区长期性水位波动引起的岩溶岸坡溶蚀劣化是危岩崩塌灾害的重要诱因,查明涉水危岩带基底岩腔发育特征是重大高位崩塌灾害隐患识别的技术基础。文章选取三峡库区巫峡段为研究区域,采用多波束测深系统结合三维声呐点云数据融合分析技术,构建了一种库区岩溶岸坡水下岩腔隐患探测与识别技术方法,查明了研究区水下岩腔空间分布规律和发育特征。结果表明:(1)巫峡段共发育水下岩腔24处,66.7%与涉水危岩带共生,其中箭穿洞、黄岩窝及曲子滩危岩带发育密度最高。(2)水下岩腔平面形态有倒置漏斗形和椭圆形两类,前者受竖向构造节理扩展过程控制,后者受“溶蚀–崩塌”灾变耦合过程控制。(3)水下岩腔的发育受到地层岩性、斜坡结构和褶皱构造的多因素协同控制,岩性上集中于三叠系嘉陵江组三段(T1j3)薄–中层灰岩夹泥质灰岩(占比62.5%),构造上在神女峰背斜、青石背斜核部地层接触带以及神女溪−官渡口向斜南翼形成了3个优势发育区,斜坡结构上以水平坡(41.7%)和斜交坡(29.2%)为主,大规模岩腔主要发育在斜交坡中。研究结果精准地掌握了三峡库区巫峡段危岩消落带水下岩腔发育状况,为后续开展针对性危岩监测、加固等防护措施提供了科学依据。 展开更多
关键词 多波束声呐 水下地形测量 危岩体 消落带 岩溶岸坡水下岩腔识别
暂未订购 下载PDF
湖水位骤降下浸水路基边坡稳定性演化规律及预警模型 认领 引用
18
作者 李永威 陈风帆 +2 位作者 童立红 丁海滨 徐林荣 《中南大学学报（自然科学版）》 EI CSCD 北大核心 2026年第6期2688-2700,共13页
针对湖滨铁路浸水路基边坡在水位骤降与列车动载耦合作用下灾变机制复杂、临灾预警困难等问题,研究浸水路基边坡稳定性及预警模型。首先,根据建立的浸水路基边坡稳定性的计算公式,研究水位下降速率和初始水位高度对路基边坡稳定性的影响... 针对湖滨铁路浸水路基边坡在水位骤降与列车动载耦合作用下灾变机制复杂、临灾预警困难等问题,研究浸水路基边坡稳定性及预警模型。首先,根据建立的浸水路基边坡稳定性的计算公式,研究水位下降速率和初始水位高度对路基边坡稳定性的影响;其次,确定了路基边坡水位下降速率阈值与警戒水位高度阈值;第三,根据运动学特征、现场宏观现象及铁路安全运营需求,确定了该案例路基边坡的变形、加速度和位移的预警阈值;最后,建立了以“警戒水位高度—水位下降速率—变形速率”为核心预警指标的浸水路基边坡四级预警模型,并提出了“三步走”的预警方法,通过现场报告验证了其合理性。研究结果表明:在水位下降过程中,路基边坡稳定性逐渐降低至最低点后逐渐回升,稳定性最低点在边坡高度1/5~3/10处;当水位以0.07 m/d和0.20 m/d速率下降时,路基边坡分别处于欠稳定和不稳定状态。存在一个危险警戒水位高度,为坡高的0.65。 展开更多
关键词 浸水路基边坡 水位下降 边坡稳定性 变形预警 水位预警 预警模型
暂未订购 下载PDF
深水放空洞冰塞封堵技术体系构想与可行性初探 认领 引用
19
作者 刘海祥 唐云清 +4 位作者 胡继洲 曹翔宇 陈西宁 高攀峰 柯敏勇 《三峡大学学报（自然科学版）》 CAS 北大核心 2026年第3期66-75,共10页
大量已建水库的深水放空洞长期处于高水头工况,衬砌老化、闸门启闭失灵及局部冲蚀等问题增多,深水检修和可控封堵需求愈加迫切.现有混凝土堵头、刚性钢结构及橡胶气囊等方案在深水应急条件下存在施工周期长、可逆性差或稳定裕度不足等局... 大量已建水库的深水放空洞长期处于高水头工况,衬砌老化、闸门启闭失灵及局部冲蚀等问题增多,深水检修和可控封堵需求愈加迫切.现有混凝土堵头、刚性钢结构及橡胶气囊等方案在深水应急条件下存在施工周期长、可逆性差或稳定裕度不足等局限,难以满足不断库检修要求.本文提出利用闸门上游洞内水体在冷却与保温系统作用下冻结形成冰塞,由冰塞与混凝土衬砌协同承压,构建面向深水放空洞应急维修的冰塞封堵体系.围绕冰塞体热-水-力耦合、多尺度受力及深水高效成冰与施工安全控制等问题,构建由理论分析、试验研究和三维数值仿真组成的研究主线.大比尺水下模型试验验证了水下冷凝管成冰工法在接近工程尺度下的成冰可控性与初始承压能力;三维传热分析表明冷量损失主要集中于冰-水界面对流换热;三维力学仿真表明冰塞长径比和界面参数是控制极限承载能力及破坏模式的主导因素.相关结果为深水放空洞冰塞封堵技术由工程构想走向工程应用提供了可行性依据. 展开更多
关键词 深水放空洞 深水检修 冰塞封堵体系 大比尺试验 仿真分析
暂未订购 下载PDF
我国西南地区大型水库消落带植物功能多样性对淹水持续时间的响应特征及生态启示 认领 引用
20
作者 江维薇 余慧怡 肖衡林 《湖泊科学》 EI CAS CSCD 北大核心 2026年第4期1598-1610,I0018,I0019,共13页
为探究淹水持续时间对大型水库消落带植物功能多样性的调控机制,以西南地区3座大型水库为研究区,系统测定了不同淹水持续时间下消落带植物功能性状及功能多样性指标。结果发现:(1)调查共记录维管植物17科30属34种,盖度≥25%的优势物种共... 为探究淹水持续时间对大型水库消落带植物功能多样性的调控机制,以西南地区3座大型水库为研究区,系统测定了不同淹水持续时间下消落带植物功能性状及功能多样性指标。结果发现:(1)调查共记录维管植物17科30属34种,盖度≥25%的优势物种共8种。(2)中度淹水区(MF)功能多样性最高,显著高于轻度(SF)和重度淹水区(LF),优势物种性状分异及生态位分化显著。(3)LF区功能同质化明显,各功能多样性指数显著下降,仅主根直径显著增加(较MF、SF区分别高63%和154%),表明强淹水胁迫下群落通过特异增粗主根构建功能冗余结构;狗牙根(Cynodon dactylon)为高度特化的关键物种。(4)SF区的群落郁闭度、茎分支数、主根长以及根总鲜重显著高于MF和LF区,表明该区环境筛选出具有快速拓殖能力的性状组合;而狗牙根、牛筋草(Eleusine indica)、藿香蓟(Ageratum conyzoides)和苍耳(Xanthium sibiricum)的性状空间呈现分散独立的格局。(5)叶片性状变异系数在各淹水梯度均较大,印证其对淹水环境的敏感性。综上表明,在西南水库消落带,淹水持续时间是调控功能性状分散程度与功能多样性的关键驱动因子,年均淹没≥180 d的LF区侧重功能冗余策略;年均淹没<180 d的区域侧重功能互补策略。淹水梯度上的功能多样性响应差异,驱动了优势种形成多种适应性策略,因此可依据淹水持续时间实施差异化群落构建。 展开更多
关键词 西南水库 水库消落带 优势种 功能性状 功能多样性
暂未订购 下载PDF
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
上一页 1 2 … 26 下一页 到第 页
在线咨询 使用帮助 返回顶部 意见反馈