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井塔冬期快速施工成套技术 1

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Thermo-mechanical simulation of frost heave in saturated soils

《结构与土木工程前沿(英文)》   页码 1400-1412 doi: 10.1007/s11709-023-0990-x

摘要: Roads are exposed to various degradation mechanisms during their lifetime. The pavement deterioration caused by the surrounding environment is particularly severe in winter when the humidity and subfreezing temperatures prevail. Frost heave-induced damage is one of the winter-related pavement deterioration. It occurs when the porewater in the soil is exposed to freezing temperatures. The study of frost heave requires conducting a multiphysics analysis, considering the thermal, mechanical, and hydraulic fields. This paper presents the use of a coupled thermo-mechanical approach to simulate frost heave in saturated soils. A function predicting porosity evolution is implemented to couple the thermal and mechanical field analyses. This function indirectly considers the effect of the water seepage inside the soil. Different frost heave scenarios with uniform and non-uniform boundary conditions are considered to demonstrate the capabilities of the method. The results of the simulations indicate that the thermo-mechanical model captures various processes involved in the frost heave phenomenon, such as water fusion, porosity variation, cryogenic suction force generation, and soil expansion. The characteristics and consequences of each process are determined and discussed separately. Furthermore, the results show that non-uniform thermal boundaries and presence of a culvert inside the soil result in uneven ground surface deformations.

关键词: frost heave     multiphysics analysis     thermo-mechanical approach     saturated soils    

Frost heave and freezing processes of saturated rock with an open crack under different freezing conditions

Zhitao LV, Caichu XIA, Yuesong WANG, Ziliang LIN

《结构与土木工程前沿(英文)》 2020年 第14卷 第4期   页码 947-960 doi: 10.1007/s11709-020-0638-z

摘要: Frost heave experiments on saturated sandstone and tuff with an open crack are conducted under uniform and unidirectional freezing conditions. Frost heave of crack in sandstone with high permeability is more significant under uniform freezing condition than that under unidirectional freezing condition. However, frost heave of crack in tuff with low permeability is more significant under unidirectional freezing condition. To illustrate the reasons for this phenomenon, a numerical model on the freezing processes of saturated rock with an open crack considering the latent heat of pore water and water in crack is proposed and confirmed to be reliable. Numerical results show that a frozen shell that blocks the migration of water in crack to rock develops first in the outer part of the rock before the freezing of water in crack under uniform freezing condition. However, the migration path of water in crack to the unfrozen rock under freezing front exists under unidirectional freezing condition. The freezing process and permeability of rock together determine the migration of water in crack and lead to the different frost heave modes of crack for various permeable rocks under different freezing conditions. The frost heave modes of crack in rock with low or high permeability are similar under uniform freezing condition because water migration is blocked by a frozen shell and is irrelevant to rock permeability. For high permeability rock, the frost heave of crack will be weakened due to water migration under unidirectional freezing condition; however, the frost heave of crack would be more significant for low permeability rock because water migration is blocked under unidirectional freezing condition. Therefore, the freezing condition and rock permeability determine the frost heave of rock with crack together, and this should be concerned in cold regions engineering applications.

关键词: frost heave     rock with crack     freezing process     freezing condition     frost heave mode    

Experimental investigations of frost release by hydrophilic surfaces

Zhongliang LIU, Lingyan HUANG, Yujun GOU, Yaomin LIU

《能源前沿(英文)》 2010年 第4卷 第4期   页码 475-487 doi: 10.1007/s11708-010-0114-x

摘要: Frost formation occurs when water vapor in the surrounding air comes into contact with cold surfaces through heat and mass transfer. It is usually an undesirable phenomenon in most refrigeration and cryogenic systems. A few studies have shown that changing the surface energy, such as increasing the surface hydrophilicity or hydrophobicity, has significant effects on frost growth. In this paper, a kind of hydrophilic polymer paint is formulated to counteract frost deposition on cold surfaces. The coated surface can retard frost formation up to three hours under low plate temperatures (-15.3°C) and high air humidity (72%). To test the antifrosting performance of the hydrophilic paint under more practical conditions, it is applied to a fin-and-tube heat exchanger and a domestic refrigerator at a coating thickness of 30 μm. Comparisons of frost deposition, pressure drops, and outlet temperatures are made between uncoated and coated heat exchangers. Under conditions of high air temperature (2.2°C) and relative high air humidity (90%), the paint prolongs the defrosting interval from 80 to 137 min. Experimental observations also show that the coated hydrophilic fins are free of frost deposition during the entire course of the test and that the coating has no significant additional thermal resistance.

关键词: frost formation     hydrophilicity     heat and mass transfer     performance    

Seepage failure by heave in sheeted excavation pits constructed in stratified cohesionless soils

Serdar KOLTUK, Jie SONG, Recep IYISAN, Rafig AZZAM

《结构与土木工程前沿(英文)》 2019年 第13卷 第6期   页码 1415-1431 doi: 10.1007/s11709-019-0565-z

摘要: In this study, experimental and numerical investigations are performed to clarify the seepage failure by heave in sheeted excavation pits in stratified cohesionless soils in which a relatively permeable soil layer ( ) lies above a less permeable soil layer ( ) between excavation base and wall tip. It is shown that the evaluation of base stabilities of excavation pits against seepage failure by using Terzaghi and Peck’s approach leads to considerably lower critical potential differences than those obtained from the model tests. On the other hand, a relatively good agreement is achieved between the results of the model tests and the finite element (FE) analyses. Further investigations are performed by using axisymmetric excavation models with various dimensions and ground conditions, and a comparison between the results obtained from Terzaghi and Peck’s approach and finite element analyses is given.

关键词: seepage failure by heave     cohesionless stratified soil     model test     Terzaghi and Peck’s approach     FE analysis    

Experimental investigation and ANN modeling on improved performance of an innovative method of using heave

Srinivasan CHANDRASEKARAN, Arunachalam AMARKARTHIK, Karuppan SIVAKUMAR, Dhanasekaran SELVAMUTHUKUMARAN, Shaji SIDNEY

《能源前沿(英文)》 2013年 第7卷 第3期   页码 279-287 doi: 10.1007/s11708-013-0268-4

摘要: To convert wave energy into usable forms of energy by utilizing heaving body, heaving bodies (buoys) which are buoyant in nature and float on the water surface are usually used. The wave exerts excess buoyancy force on the buoy, lifting it during the approach of wave crest while the gravity pulls it down during the wave trough. A hydraulic, direct or mechanical power takeoff is used to convert this up and down motion of the buoy to produce usable forms of energy. Though using a floating buoy for harnessing wave energy is conventional, this device faces many challenges in improving the overall conversion efficiency and survivability in extreme conditions. Up to the present, no studies have been done to harness ocean waves using a non-floating object and to find out the merits and demerits of the system. In the present paper, an innovative heaving body type of wave energy converter with a non-floating object was proposed to harness waves. It was also shown that the conversion efficiency and safety of the proposed device were significantly higher than any other device proposed with floating buoy. To demonstrate the improvements, experiments were conducted with non-floating body for different dimensions and the heave response was noted. Power generation was not considered in the experiment to observe the worst case response of the heaving body. The device was modeled in artificial neural network (ANN), the heave response for various parameters were predicted, and compared with the experimental results. It was found that the ANN model could predict the heave response with an accuracy of 99%.

关键词: ocean wave energy     point absorbers     heaving body     non-floating object     heave response ratio     artificial neural network (ANN)    

青藏高原多年冻土地带爆破研究

何广沂

《中国工程科学》 2001年 第3卷 第6期   页码 57-64

摘要:

介绍了青藏高原多年冻土地带铁路试验工程中有关爆破方面的研究成果,针对多年冻土的特征,重点论述了爆破方法与工艺及先进实用的聚能爆破技术。

关键词: 多年冻土     路堑     基坑     钻孔     聚能弹     聚能爆破    

升沉补偿装置虚拟样机协同设计及仿真分析

吕东,何将三,刘少军,黄锴

《中国工程科学》 2004年 第6卷 第3期   页码 36-40

摘要:

采用参数并行集成化方法设计深海采矿升沉补偿装置的虚拟样机,并进行了虚拟试验仿真研究,探讨协同设计在复杂机电系统中的具体应用,为深海开采系统总体设计提供设计理论参考。

关键词: 升沉补偿     虚拟样机     协同设计     仿真    

Laboratory experiment on using non-floating body to generate electrical energy from water waves

Arunachalam AMARKARTHIK, Srinivasan CHANDRASEKARAN, Karuppan SIVAKUMAR, Harender SINHMAR

《能源前沿(英文)》 2012年 第6卷 第4期   页码 361-365 doi: 10.1007/s11708-012-0210-1

摘要: This paper describes an innovative method of using a non-buoyant body to harness ocean waves. All the point absorbers are buoyant in nature and move up due to buoyancy and come down because of gravity. The point absorbers are designed to move along the waves to make the device efficient. These devices face excessive stress during the rough weather on account of the extreme motion of waves and cause the total device failure. The present study shows that using a non-buoyant body for conventional point absorber principle is much efficient and safer than any other device proposed till today. A small scale wave energy converter with non-buoyant body was designed, fabricated and tested in small scale wave maker. An electrical generator was coupled with the device to generate electrical energy from harnessed waves. The generator was electrically loaded and the generated power was measured. It was found from the experiments that the proposed device showed a significant improvement in electricity generation and safety during extreme conditions. In addition to the electricity generation, the characteristics of the device were also studied by using various wave and device parameters.

关键词: ocean wave energy     point absorbers     heaving body     non-floating object     heave response ratio     electrical energy generation    

analysis of cold responsive proteins in two wheat cultivars with different tolerance to spring radiation frost

Shujuan ZHANG,Guoqi SONG,Yulian LI,Jie GAO,Jiao WANG,Guiju CHEN,Haosheng LI,Genying LI,Zhendong ZHAO

《农业科学与工程前沿(英文)》 2014年 第1卷 第1期   页码 37-45 doi: 10.15302/J-FASE-2014008

摘要: Spring radiation frost (SRF) is a severe environmental stress which impairs wheat yield and productivity worldwide. To better understand the mechanism of wheat ( ) responding to SRF, a comparative proteomic analysis was performed to analyze the changes of the key proteins in two wheat cultivars Jimai22 and Luyuan301 with high and low tolerance to SRF respectively. A total of 43 differentially expressed proteins (DEPs) which mainly involved in carbohydrate metabolism, amino acid metabolism, resistance proteins and antioxidant enzymes, photosynthesis and cellular respiration proteins, cell-wall related proteins, protein translation/processing/degradation and signal transduction were isolated and identified by two-dimensional electrophoresis and MALDI-TOF-TOF MS. The results revealed that of the 21 DEPs in Jimai22 responding to the SRF, 13 DEPs were upregulated and 8 DEPs were downregulated, and that of the 22 DEPs in Luyuan301, 9 DEPs were upregulated and 13 DEPs were downregulated. These DEPs might be responsible for the stronger cold resistance of Jimai22 compared to Luyuan301. The expression pattern and function analysis of these DEPs were very significant to understanding the mechanism of the SRF responses in wheat.

关键词: common wheat     spring radiation frost     proteomic analysis     2-DE     MALDI-TOF-TOF MS    

高寒地区混凝土井塔快速施工关键技术的研究

吴春杰,程正觉,国重宽,刘慧

《中国工程科学》 2011年 第13卷 第11期   页码 72-80

摘要:

在西北高寒地区钢筋混凝土井塔施工中,通过对桩基范围人工冻土的快速解冻技术和高寒地区冬期井塔快速施工成套技术的研究应用,确保了工程质量,加快了井塔桩基和冬期井塔主体的施工速度,缩短了井塔施工工期,解决了高寒地区煤矿建设周期长的施工技术瓶颈问题。

关键词: 西北高寒地区     钢筋混凝土井塔     人工冻融土     快速解冻     冬期     井塔冬期快速施工成套技术    

标题 作者 时间 类型 操作

Thermo-mechanical simulation of frost heave in saturated soils

期刊论文

Frost heave and freezing processes of saturated rock with an open crack under different freezing conditions

Zhitao LV, Caichu XIA, Yuesong WANG, Ziliang LIN

期刊论文

Experimental investigations of frost release by hydrophilic surfaces

Zhongliang LIU, Lingyan HUANG, Yujun GOU, Yaomin LIU

期刊论文

Seepage failure by heave in sheeted excavation pits constructed in stratified cohesionless soils

Serdar KOLTUK, Jie SONG, Recep IYISAN, Rafig AZZAM

期刊论文

Experimental investigation and ANN modeling on improved performance of an innovative method of using heave

Srinivasan CHANDRASEKARAN, Arunachalam AMARKARTHIK, Karuppan SIVAKUMAR, Dhanasekaran SELVAMUTHUKUMARAN, Shaji SIDNEY

期刊论文

青藏高原多年冻土地带爆破研究

何广沂

期刊论文

升沉补偿装置虚拟样机协同设计及仿真分析

吕东,何将三,刘少军,黄锴

期刊论文

Laboratory experiment on using non-floating body to generate electrical energy from water waves

Arunachalam AMARKARTHIK, Srinivasan CHANDRASEKARAN, Karuppan SIVAKUMAR, Harender SINHMAR

期刊论文

analysis of cold responsive proteins in two wheat cultivars with different tolerance to spring radiation frost

Shujuan ZHANG,Guoqi SONG,Yulian LI,Jie GAO,Jiao WANG,Guiju CHEN,Haosheng LI,Genying LI,Zhendong ZHAO

期刊论文

高寒地区混凝土井塔快速施工关键技术的研究

吴春杰,程正觉,国重宽,刘慧

期刊论文