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Pressure from surrounding rock of three shallow tunnels with large section and small spacing 被引量:18
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作者 杨小礼 金启云 马军秋 《Journal of Central South University》 SCIE EI CAS 2012年第8期2380-2385,共6页
With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the... With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the security and economy of tunnel engineering, and the calculation of pressure from the surrounding rock during the excavation is one of the problems that need to be solved urgently. Based on the practical engineering of three tunnels, the load model of three tunnels was proposed in consideration of the interaction and excavation sequence between tunnels. In comparison with the load model of single tunnel, the construction mechanical characteristics of the three tunnels were analyzed. The results show that the rock pressure of three tunnels calculated by the current tunnel design code is not reliable, and the interaction force increases with the spacing between tunnels. 展开更多
关键词 three-tunnel model large section small clear spacing load model
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Similar simulation study on the deformation and failure of surrounding rock of a large section chamber group under dynamic loading 被引量:10
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作者 Xuesheng Liu Shilin Song +4 位作者 Yunliang Tan Deyuan Fan Jianguo Ning Xuebin Li Yanchun Yin 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2021年第3期495-505,共11页
Large and super-large section chamber groups in coal mines are frequently affected by dynamic loads resulting from production activities such as roadway driving and blasting.The stability of the surrounding rock is po... Large and super-large section chamber groups in coal mines are frequently affected by dynamic loads resulting from production activities such as roadway driving and blasting.The stability of the surrounding rock is poor,and it is difficult to control.In this paper,a similar simulation test was used to study the deformation and evolution laws of the surrounding rock of a triangle-shaped chamber group under different dynamic loads.The results showed that under dynamic loading,the vertical stress of the surrounding rock of the chamber group increased in an oscillatory form.The maximum stress concentration coefficient reached 4.09.The damage degree of the roof was greater than that of the two sides.The deformation of the roof was approximately 1.2 times that of the two sides.For the chamber closer to the power source,the stress oscillation amplitude of the surrounding rock was larger,and the failure was more serious.The force of the anchorage structure showed a phased increasing characteristic;additionally,the force of the anchorage structure on the adjacent side of the chambers was greater than that on the other side.This study reveals the deformation and failure evolution laws of the surrounding rock of large section chamber groups under dynamic loading. 展开更多
关键词 Dynamic disturbance large section chamber group Deformation and failure Similar simulation test
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Application of 3D-computed tomography angiography technology in large meningioma resection 被引量:9
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作者 Jian-Qiang Chen Yin Guan +5 位作者 Gang Li Xiao-Hua Li Yue-Fu Zhan Xiang-Yin Li Liu Nie Xiang-Jun Han 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2012年第7期577-581,共5页
Objective:To discuss the role of 3D-computed tomography angiography(3D-CTA) technology in reducing injuries of large meningioma surgery.Methods:3D-CTA preoperative examinations were done in 473 patients with large men... Objective:To discuss the role of 3D-computed tomography angiography(3D-CTA) technology in reducing injuries of large meningioma surgery.Methods:3D-CTA preoperative examinations were done in 473 patients with large meningioma(simulated group).The images were analyzed by 30 post-processing workstation.By observing the major intracranial blood vessels,venous sinus,and the compression and invasion pattern in the nerve region,assessing risk level of the surgery,simulating the surgical procedures,the surgical removal plan,surgical routes and tumor blood-supplying artery embolisation plan were performed.Two hundred and fifty seven large meningioma patients who didn’t underwent 3D-CTA preoperative examination served as control group.The incidence of postoperative complications,intraoperative blood transfusion and the operation time were compared between these two groups.Results:Compared with the control group,the Simpson’s grade 1 and 11 resection rate was 80.3%(380/473),similar with that of the control(81.3%,209/257).The incidence of postoperative complications in 3D-CTA simulated group was 37.0%which was significantly lower than that(48.2%) of the control(P【0.01). The intraoperative blood supply for simulated group and the control was(523.4±208.1) mL and (592.0±263.3) mL,respectively,with significant difference between two groups(P【0.01).And the operation time[(314.8±106.3)]min was significantly lower in simulated group than that in the control[(358.4±147.9) min](P【0.01).Conclusions:Application of 3D-CTA imaging technology in risk level assessment before large-scaled meningioma resection could assist in the rational planning of tumor resectin,surgical routes,and is helpful in reducing injuries and complications and enhancing the prognosis of the patients. 展开更多
关键词 MENINGIOMA ANGIOGRAPHY Body-section RADIOGRAPHY large
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High prestress truss cable support principle and its application in large cross section coal roadway 被引量:1
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作者 姚精明 何富连 萧潇 《Journal of Coal Science & Engineering(China)》 2007年第1期18-21,共4页
With the enlarge of cross section of roadway, the radius of plastic area and broken area increase, and the tensile stress and shear stress distributing in roof coal-rock layers relevantly increase, which induce suppor... With the enlarge of cross section of roadway, the radius of plastic area and broken area increase, and the tensile stress and shear stress distributing in roof coal-rock layers relevantly increase, which induce support effect not obvious for ordinary bolt(cable). While bounding point and support structure of the truss cable is in vertex angle of roadway, and supplies coal-rock layers in bounding area with the horizontal and vertical pressure, so it settles the support problems in large cross section coal roadway. From the point of view of mechanics, gave emphasis on the invalid mechanics of ordinary bolt (cable) in large cross section coal roadway and supported mechanics of prestress truss cable. The author successfully used this technique in Wuyang Mine, and had the huge economic efficiency and the social benefit. 展开更多
关键词 truss cable large cross section roadway ordinary bolt (cable) PRESTRESS
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Intelligent optimization of the structure of the large section highway tunnel based on improved immune genetic algorithm 被引量:1
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作者 Hai-tao Bo1,Xiao-feng Jia2,Xiao-rui Wang11.School of Civil Engineering and Mechanics,Huazhong University of Science and Technology, Wuhan 430074 2.Department of Chemistry and Bioengineering,Nanyang Institute of Technology,Nanyang 473004,China. 《Journal of Pharmaceutical Analysis》 SCIE CAS 2009年第3期163-166,共4页
As in the building of deep buried long tunnels,there are complicated conditions such as great deformation,high stress,multi-variables,high non-linearity and so on,the algorithm for structure optimization and its appli... As in the building of deep buried long tunnels,there are complicated conditions such as great deformation,high stress,multi-variables,high non-linearity and so on,the algorithm for structure optimization and its application in tunnel engineering are still in the starting stage. Along with the rapid development of highways across the country,it has become a very urgent task to be tackled to carry out the optimization design of the structure of the section of the tunnel to lessen excavation workload and to reinforce the support. Artificial intelligence demonstrates an extremely strong capability of identifying,expressing and disposing such kind of multiple variables and complicated non-linear relations. In this paper,a comprehensive consideration of the strategy of the selection and updating of the concentration and adaptability of the immune algorithm is made to replace the selection mode in the original genetic algorithm which depends simply on the adaptability value. Such an algorithm has the advantages of both the immune algorithm and the genetic algorithm,thus serving the purpose of not only enhancing the individual adaptability but maintaining the individual diversity as well. By use of the identifying function of the antigen memory,the global search capability of the immune genetic algorithm is raised,thereby avoiding the occurrence of the premature phenomenon. By optimizing the structure of the section of the Huayuan tunnel,the current excavation area and support design are adjusted. A conclusion with applicable value is arrived at. At a higher computational speed and a higher efficiency,the current method is verified to have advantages in the optimization computation of the tunnel project. This also suggests that the application of the immune genetic algorithm has a practical significance to the stability assessment and informationization design of the wall rock of the tunnel. 展开更多
关键词 immune genetic algorithm TUNNEL super-large section OPTIMIZATION
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Stability Analysis of Large Section Rocky Tunnel Support Structure
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作者 Chaofan Si Jinhai Gao Yahui Li 《World Journal of Engineering and Technology》 2023年第2期234-245,共12页
In order to study the stress characteristics of the initial support and secondary lining of the large section tunnel and to solve the problem of secondary lining cracking during operation. Taking the large section tun... In order to study the stress characteristics of the initial support and secondary lining of the large section tunnel and to solve the problem of secondary lining cracking during operation. Taking the large section tunnel in Zihong village, Qi County as the research object, a numerical simulation method was used to establish a finite element model of the large section tunnel. So as to simulate and analyze the stress characteristics of the support structure of this tunnel. Through the simulation of the initial support and second lining of this large section tunnel in terms of displacement, stress, plastic zone damage and anchor shaft force, the results show that as the excavation progresses, the stress and displacement on the surface of the newly excavated tunnel profile is faster, especially at the side walls and arch footings, the stress and displacement values are slightly larger than other characteristic points, but the final values are stable and converge, and are basically consistent with the field monitoring results, which indicates that this support system is basically in stable state. Therefore, during the tunnel excavation and support process, special attention should be paid to the stability of the sidewalls and footings, and the results of this study will be of great practical significance for tunnel construction and maintenance. 展开更多
关键词 large section Tunnel Initial Support Secondary Lining Numerical Simulation STABILITY
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Dynamic evolution in mechanical characteristics of complex supporting structures during large section tunnel construction
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作者 Hua Jiang Jianhua Mu +3 位作者 Jinxun Zhang Yusheng Jiang Chongyang Liu Xiaoyan Zhang 《Deep Underground Science and Engineering》 2022年第2期183-201,共19页
The shallow tunnelling method(STM)often uses temporary supports to divide large section tunnels into several closed or semiclosed sections so as to share the upper load.The complex support system composed of primary a... The shallow tunnelling method(STM)often uses temporary supports to divide large section tunnels into several closed or semiclosed sections so as to share the upper load.The complex support system composed of primary and temporary supports can ensure safety during tunnel construction.Based on the large section tunnel of Beijing Subway Line 12,the mechanical characteristics of support system by the double-side-drift method(DSDM)during excavation and demolition were analyzed through numerical simulation and monitoring.The study showed that the middle cave excavation was the most critical stage of the DSDM,during which the load on the supporting structure increased significantly.The temporary vertical support bore most of the new load during middle cave excavation.During the demolition stage,the load was redistributed,which caused arch settlement and section convergence.The removal of the temporary vertical support exerted the greatest impact in this process.The lateral temporary inverted arch changed from axial compression to axial tension after the middle and lower caves were excavated.Based on the mechanical characteristics of the support system,some engineering suggestions were proposed for large section tunnel construction.These research results can provide reference for the design and construction of similar large section tunnels. 展开更多
关键词 large section tunnel mechanical characteristics on-site monitoring supporting structure the shallow tunnelling method
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Crack elongation and its width of large depth reinforced concrete beams 被引量:2
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作者 管俊峰 赵顺波 黄承逵 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2010年第5期631-635,共5页
In order to meet the requirement of structural inspection,the crack spacing and crack width at various heights in the tensile zone of six large depth reinforced concrete beams were measured under several loading level... In order to meet the requirement of structural inspection,the crack spacing and crack width at various heights in the tensile zone of six large depth reinforced concrete beams were measured under several loading levels of serviceability state.The effects of the depth of normal section beams on the crack spacing and crack width were analyzed,and the modified model is proposed for calculating the average crack spacing by thinking about the depth of normal section,the reinforcement arrangement and the effective reinforcement ratio.The relationships of crack widths at any position in the tensile zone and at the reinforcement level on the side surface of beam were studied.By theoretical and statistical analysis,a method is proposed to calculate the ratios of crack widths between any position and the reinforcement level on the side surface of large depth reinforced concrete beams. 展开更多
关键词 reinforced concrete beam large depth of normal section crack elongation average crack spacing ratio of crack width
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Simulation of the RCS Range Resolution of Extremely Large Target 被引量:1
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作者 WANGSheng XIONGQiant +2 位作者 JIANGAi-ping XIAYing-qing XuPeng-gen 《Wuhan University Journal of Natural Sciences》 EI CAS 2005年第2期410-412,共3页
The high frequency hybrid technique based on an iterative Physical Optics(PC)) and the method of equivalent current (MEC) approach is developed for predicting rangeresolution of the Radar Cross Section (RCS) in the sp... The high frequency hybrid technique based on an iterative Physical Optics(PC)) and the method of equivalent current (MEC) approach is developed for predicting rangeresolution of the Radar Cross Section (RCS) in the spatial domain. We introduce the hybrid highfrequency method to simulate range resolution of the extremely large target in the near zone. Thispaper applies this method to simulate the range resolution of the two 1 m X 1 m plates and the ship.The study improves the speed of simulatingthe range resolution of the extremely large target and isprepared for the application of the extrapolation and interpolation in the spatial domain. 展开更多
关键词 near-zone extremely large target Radar Cross section(RCS) range resolution
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Dynamic plastic response of clamped stiffened plates with large deflection 被引量:1
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作者 彭英 杨平 《Journal of Marine Science and Application》 2008年第2期82-90,共9页
Study on the dynamic response, and especially the nonlinear dynamic response of stiffened plates is complicated by their discontinuity and inhomogeneity. The finite element method (FEM) and the finite strip method are... Study on the dynamic response, and especially the nonlinear dynamic response of stiffened plates is complicated by their discontinuity and inhomogeneity. The finite element method (FEM) and the finite strip method are usually adopted in their analysis. Although many useful conclusions have been obtained, the computational cost is enormous. Based on some assumptions, the dynamic plastic response of clamped stiffened plates with large deflections was theoretically investigated herein by a singly symmetric beam model. Firstly, the deflection conditions that a plastic string must satisfy were obtained by the linearized moment-axial force interaction curve for singly symmetric cross sections and the associated plastic flow rule. Secondly, the possible motion mechanisms of the beam under different load intensity were analysed in detail. For structures with plastic deformations, a simplified method was then given that the arbitrary impact load can be replaced equivalently by a rectangular pulse. Finally, to confirm the validity of the proposed method, the dynamic plastic response of a one-way stiffened plate with four fully clamped edges was calculated. The theoretical results were in good agreement with those of FEM. It indicates that the present calculation model is easy and feasible, and the equivalent substitution of load almost has no influence on the final deflection. 展开更多
关键词 dynamic plastic response stiffened plates large deflection singly symmetric cross section
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Taxonomy and phylogeny of the section Chaetoceros(Chaetocerotaceae,Bacillariophyta),with description of two new species
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作者 Xudan LU Mengyi ZHAI +1 位作者 Nina LUNDHOLM Yang LI 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第4期1286-1311,共26页
Chaetoceros Ehrenberg is one of the most diverse genera of planktonic diatoms.The species in section Chaetoceros are characterized by cells and setae having numerous chloroplasts and being widely distributed.However,t... Chaetoceros Ehrenberg is one of the most diverse genera of planktonic diatoms.The species in section Chaetoceros are characterized by cells and setae having numerous chloroplasts and being widely distributed.However,the delimitations of some species are problematic because of limited morphological information in the classical descriptions.Monoclonal strains of the section Chaetoceros were established,morphological features were studied using light and electron microscopy,and the hypervariable D 1-D 3 region of the nuclear ribosomal large subunit gene was sequenced to address phylogenetic relationships.Fifteen species belonging to the section Chaetoceros were recorded,including two new species,C.hainanensis sp.nov.and C.tridiscus sp.nov.Chaetoceros hainanensis was characterized by straight chains,narrowly lanceolate to hexagonal apertures,sibling setae diverging in nearly right angles,stipule-shaped spines on terminal setae and arrowhead-shaped spines on intercalary setae.C.tridiscus had short straight chains,narrowly lanceolate apertures,arrowhead-shaped spines and circular poroids arranged in a grid pattern on terminal and intercalary setae.The phylogenetic analyses revealed six groups formed by 19 species within the section Chaetoceros,which was found to be monophyletic.The subdivision of the section is still not well understood.The morphological characters within each group varied considerably and molecular information on more species are needed to enrich the phylogenetic profiling. 展开更多
关键词 morphology large subunit ribosomal RNA encoding gene(LSU) section Chaetoceros Chaetoceros hainanensis Chaetoceros tridiscus
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Dating of Speleothems Section in Shihua Cave,Beijing
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作者 Jinbo Lü Beijing Geological Survey,Beijing 102206,China. 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期292-292,共1页
Beijing Shihua Cave is located at the northeastern part of the granite fringed Paleozoic to Mesozoic synclinal belt in Fangshan,which is face to face with the Peking Man(Homo erectus pekinensis) Relic Site.The stratig... Beijing Shihua Cave is located at the northeastern part of the granite fringed Paleozoic to Mesozoic synclinal belt in Fangshan,which is face to face with the Peking Man(Homo erectus pekinensis) Relic Site.The stratigraphy sequence is composed of Majiagou Formation limestone formed before 460 Ma in Middle Ordovician.The large forms of cave began to 展开更多
关键词 Quaternary section of SPELEOTHEM STALAGMITE microbanding superimposed relationship of STALAGMITE large forms of CAVE BEIJING Shihua CAVE
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Artificial intelligence recognition of pathological T stage and tumor invasion in rectal cancer based on large panoramic pathological sections
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作者 Yiheng Ju Longbo Zheng +6 位作者 Peng Zhao Fangjie Xin Fengjiao Wang Yuan Gao Xianxiang Zhang Dongsheng Wang Yun Lu 《Intelligent Medicine》 2022年第3期141-151,共11页
Background The incidence of colorectal cancer is increasing worldwide,and it currently ranks third among all cancers.Moreover,pathological diagnosis is becoming increasingly arduous.Artificial intelligence has demon-s... Background The incidence of colorectal cancer is increasing worldwide,and it currently ranks third among all cancers.Moreover,pathological diagnosis is becoming increasingly arduous.Artificial intelligence has demon-strated the ability to fully excavate image features and assist doctors in making decisions.Large panoramic patho-logical sections contain considerable amounts of pathological information.In this study,we used large panoramic pathological sections to establish a deep learning model to assist pathologists in identifying cancerous areas on whole-slide images of rectal cancer,as well as for T staging and prognostic analysis.Methods We collected 126 cases of primary rectal cancer from the Affiliated Hospital of Qingdao University West Coast Hospital District(internal dataset)and 42 cases from Shinan and Laoshan Hospital District(external dataset)that had tissue surgically removed from January to September 2019.After sectioning,staining,and scanning,a total of 2350 hematoxylin-eosin-stained whole-slide images were obtained.The patients in the internal dataset were randomly divided into a training cohort(n=88)and a test cohort(n=38)at a ratio of 7:3.We chose DeepLabV3+and ResNet50 as target models for our experiment.We used the Dice similarity coefficient,accuracy,sensitivity,specificity,receiver operating characteristic(ROC)curve,and area under the curve(AUC)to evaluate the performance of the artificial intelligence platform in the test set and validation set.Finally,we followed up patients and examined their prognosis and short-term survival to corroborate the value of T-staging investigations.Results In the test set,the accuracy of image segmentation was 95.8%,the Dice coefficient was 0.92,the accuracy of automatic T-staging recognition was 86%,and the ROC AUC value was 0.93.In the validation set,the accuracy of image segmentation was 95.3%,the Dice coefficient was 0.90,the accuracy of automatic classification was 85%,the ROC AUC value was 0.92,and the image analysis time was 0.2 s.There was a difference in survival in patients with local recurrence or distant metastasis as the outcome at follow-up.Univariate analysis showed that T stage,N stage,preoperative carcinoembryonic antigen(CEA)level,and tumor location were risk factors for postoperative recurrence or metastasis in patients with rectal cancer.When these factors were included in a multivariate analysis,only preoperative CEA level and N stage showed significant differences.Conclusion The deep convolutional neural networks we have establish can assist clinicians in making decisions of T-stage judgment and improve diagnostic efficiency.Using large panoramic pathological sections enables better judgment of the condition of tumors and accurate pathological diagnoses,which has certain clinical application value. 展开更多
关键词 large panoramic pathological sections Rectal cancer Whole-slide imaging Deep learning Survival analysis
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工艺孔对大截面部分包覆钢-混凝土组合梁受弯性能影响的试验研究 被引量:1
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作者 贾水钟 刘宏欣 +3 位作者 李亚明 孙求知 张朕磊 钱桦 《建筑结构》 北大核心 2024年第4期9-17,共9页
为了研究工艺孔对大截面部分包覆钢-混凝土组合梁(大截面PEC梁)受弯性能的影响,对5根不同构造的大截面PEC梁进行了静力试验,研究了两点加载下主次梁腹板开洞方式对大截面PEC梁试件受弯性能、延性、破坏模式等的影响规律。结果表明:静力... 为了研究工艺孔对大截面部分包覆钢-混凝土组合梁(大截面PEC梁)受弯性能的影响,对5根不同构造的大截面PEC梁进行了静力试验,研究了两点加载下主次梁腹板开洞方式对大截面PEC梁试件受弯性能、延性、破坏模式等的影响规律。结果表明:静力荷载作用下,各个试件均表现出良好的延性,腹部开孔对试件承载力和截面刚度有一定的削弱作用。型钢主钢件的应变与混凝土的应变沿截面高度方向均大致呈线性变化,符合平截面假定。按《部分包覆钢-混凝土组合结构技术规程》(T/CECS 719—2020)计算得到的开工艺孔的大截面PEC梁抗弯承载力与试验值误差较小,受尺寸效应影响不大,所采用计算公式安全可靠。 展开更多
关键词 大截面部分包覆钢-混凝土组合梁 工艺孔 破坏模式 受弯承载力 延性
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杭州电竞中心结构设计重难点概述 被引量:2
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作者 熊森 冯孝宾 +3 位作者 张卫 罗俊 鲁伟 郑小庆 《建筑结构》 北大核心 2024年第17期9-15,共7页
杭州电竞中心内圈主体结构采用钢框架-支撑结构,外圈采用“大倾角梭形斜柱+多段钢折梁框架”,是集承重与抗侧力于一体的结构体系,屋盖采用车辐式索承网格自平衡结构形式。详细介绍了地下结构、中央场馆结构的设计要点,门厅处利用建筑造... 杭州电竞中心内圈主体结构采用钢框架-支撑结构,外圈采用“大倾角梭形斜柱+多段钢折梁框架”,是集承重与抗侧力于一体的结构体系,屋盖采用车辐式索承网格自平衡结构形式。详细介绍了地下结构、中央场馆结构的设计要点,门厅处利用建筑造型空间设计为多段钢折梁与跨层桁架相结合的结构形式;室内二层至三层楼面设计一浮空弧形人行桥,截面形式为薄壁钢箱梁,桥宽2.2m,跨度57m,采用“上挂下支”的稳定结构形式。对整体结构进行了静力弹性、动力弹塑性、振动台试验、典型节点有限元、整体稳定以及局部稳定等系列分析与试验。结果表明:结构在静力荷载和地震作用下强度和刚度均满足规范要求;典型节点极限承载力为荷载设计值的4.17倍;结构整体稳定性安全系数为3.79;斜柱局部稳定安全系数为2.52。合理的设计保证了结构的安全、经济和实用性。 展开更多
关键词 杭州亚运会 杭州电竞中心 钢框架-支撑 大倾角梭形斜柱 多段钢折梁 车辐式索承网格自平衡结构
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新景矿大断面岩巷综掘技术研究与应用 被引量:1
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作者 邓鹏 《煤炭与化工》 CAS 2024年第4期10-13,共4页
为提高掘进速度,保证巷道稳定,在新景矿15号煤采区集中辅助运输巷开展了大断面岩巷综合机械化掘进技术的研究。在分析当前施工工艺以及支护中存在问题的基础上,提出了以EBZ320D掘进机和CMM2-25型锚杆钻机为主要设备的综合机械化岩巷掘... 为提高掘进速度,保证巷道稳定,在新景矿15号煤采区集中辅助运输巷开展了大断面岩巷综合机械化掘进技术的研究。在分析当前施工工艺以及支护中存在问题的基础上,提出了以EBZ320D掘进机和CMM2-25型锚杆钻机为主要设备的综合机械化岩巷掘进作业线。理论分析了锚杆索围岩强度强化理论,结合现场实际情况,设计了以不同长度锚索为主的支护方式。现场应用表明,应用新的综合机械化掘进技术后,巷道变形量小,掘进速度快,施工成本低,经济社会效益显著,应用效果良好。 展开更多
关键词 岩石巷道 大断面 巷道综掘 矿压观测
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乌东德水电站地下洞室群创新施工方法与技术
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作者 杨宗立 丁鹏 +2 位作者 安瑞楠 简崇林 彭波 《地下空间与工程学报》 CSCD 北大核心 2024年第6期2045-2053,2082,共10页
大型水电工程中巨型地下洞室群的开挖、支护施工是技术难点,根据现场实际地质条件和工作环境对地下厂房的开挖及支护工法进行改进、对施工机械进行改良,是保证地下洞室群安全、优质、高效、绿色施工的重要保障。本文针对乌东德水电站大... 大型水电工程中巨型地下洞室群的开挖、支护施工是技术难点,根据现场实际地质条件和工作环境对地下厂房的开挖及支护工法进行改进、对施工机械进行改良,是保证地下洞室群安全、优质、高效、绿色施工的重要保障。本文针对乌东德水电站大型地下洞室群施工过程中关键工法和技术难题,开展创新研发和攻关,包括:大跨度高边墙开挖施工、超大断面调压室开挖施工、小直径溜渣井式竖井开挖、不良地质段超大断面洞室支护、拔管法接触灌浆施工、洞内压力钢管拼装、多孔深竖井混凝土滑模施工、大型出线竖井施工等。从工艺类型、精细开挖、支护和装备革新技术等方面进行关键创新施工方法和技术总结,研究成果可供同类工程建设参考。 展开更多
关键词 乌东德水电站 地下洞室群 施工方法 开挖与支护 超大断面
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液化土层厚度差异下大直径变截面单桩基础振动台试验
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作者 冯忠居 金熙宾 +2 位作者 张聪 董建松 袁鑫 《土木工程学报》 EI CSCD 北大核心 2024年第11期92-105,共14页
针对地震作用下不同液化土层厚度对大直径变截面单桩基础动力响应的影响,依托实体工程设计振动台模型试验,分别从土层孔压比、桩身加速度、桩顶水平位移及桩身弯矩等方面对大直径变截面单桩基础的动力响应进行了研究,结果表明:孔压比开... 针对地震作用下不同液化土层厚度对大直径变截面单桩基础动力响应的影响,依托实体工程设计振动台模型试验,分别从土层孔压比、桩身加速度、桩顶水平位移及桩身弯矩等方面对大直径变截面单桩基础的动力响应进行了研究,结果表明:孔压比开始增长和趋于稳定的时间随液化土层厚度的增加均呈滞后趋势,液化土层厚度越薄,孔隙水上升越快,液化土层越容易发生液化。变截面位置位于液化土层时加速度增长较为明显,El-Centro波作用时大直径变截面单桩基础桩顶加速度放大系数最小,1004波作用时桩顶加速度放大系数最大;大直径变截面单桩基础桩顶水平位移最大值随液化土层厚度的增加逐渐增大,且地震波差异会影响其趋于最大值的时间;大直径变截面单桩基础最大弯矩在液化土层和非液化土层交界产生,且液化土层厚度越大地震波差异性对变截面位置处弯矩影响越大。在进行大直径变截面单桩基础的抗弯设计时,应着重考虑液化土层和非液化土层分界面处和变截面处抗弯能力。液化土层从30cm到50cm,大直径变截面单桩基础桩身加速度放大系数及桩顶位移分别增加了1.61倍和1.65倍。 展开更多
关键词 桥梁工程 液化场地 振动台试验 大直径变截面单桩基础 动力响应
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震陷土层变化下变截面单、群桩动力响应差异
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作者 冯忠居 王伟 +3 位作者 张聪 朱继新 王逸然 孟莹莹 《上海交通大学学报》 EI CAS CSCD 北大核心 2024年第7期1086-1096,共11页
为研究地震动作用下震陷土层厚度不同时大直径变截面单桩与群桩基础的动力响应差异,依托厦门第二东通道翔安大桥,通过振动台模型试验,开展震陷土层厚度30、40、50 cm时,单桩与群桩基础桩周土震陷量、桩顶水平位移、桩身加速度及弯矩动... 为研究地震动作用下震陷土层厚度不同时大直径变截面单桩与群桩基础的动力响应差异,依托厦门第二东通道翔安大桥,通过振动台模型试验,开展震陷土层厚度30、40、50 cm时,单桩与群桩基础桩周土震陷量、桩顶水平位移、桩身加速度及弯矩动力响应差异研究.结果表明:随着震陷层厚度增大,单桩与群桩基础桩周土震陷量、桩顶水平位移、桩身加速度及弯矩均逐渐增大,且加速度及弯矩在变截面处突变;同一震陷层厚度下,群桩基础桩周土震陷量较单桩大,但群桩基础加速度、桩顶水平位移及桩身弯矩均小于单桩.震陷场地桩基础设计时,应着重考虑变截面单桩与群桩动力响应差异,保证桩基础抗震性能. 展开更多
关键词 桥梁工程 大直径变截面桩 震陷土层 振动台试验 动力响应差异
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大型耙吸挖泥船结构设计要点
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作者 荆海东 杨青 谢昊 《船海工程》 北大核心 2024年第1期82-86,共5页
为实现大型耙吸挖泥船结构设计安全、合理、可靠,以某大型耙吸挖泥船为例,分析大型耙吸挖泥船结构设计特点,从结构设计、强度评估、疲劳评估和振动评估等角度论证其设计要点,通过对泥舱结构设计分析,给出泥舱设计的关键节点,对关键节点... 为实现大型耙吸挖泥船结构设计安全、合理、可靠,以某大型耙吸挖泥船为例,分析大型耙吸挖泥船结构设计特点,从结构设计、强度评估、疲劳评估和振动评估等角度论证其设计要点,通过对泥舱结构设计分析,给出泥舱设计的关键节点,对关键节点进行强度分析和疲劳分析,结果表明,该船局部关键区域应力水平较高,低周疲劳在关键区域的疲劳中占据主要地位,建立三维有限元模型计算挖泥船固有频率,对比该大型耙吸挖泥船激励频率与固有频率,结果表明,船体总振动固有频率通常可以避开激励频率,生活楼固有频率与激励频率较为接近。 展开更多
关键词 大型耙吸挖泥船 结构设计 中剖面设计 关键区域 强度评估 疲劳评估 振动控制
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