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Thermal performance of cast-in-place piles with artificial ground freezing in permafrost regions

Journal of Mountain Science 2024年第4期21卷 1307-1328页

作者： WANG Xinbin CHEN Kun YU Qihao GUO Lei you yanhui JIN Mingyang State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

During the construction of cast-in-place piles in warm permafrost,the heat carried by concrete and the cement hydration reaction can cause strong thermal disturbance to the surrounding permafrost.Since the bearing capacity of the pile is quite small before the full freeze-back,the quick refreezing of the native soils surrounding the cast-in-place pile has become the focus of the infrastructure construction in permafrost.To solve this problem,this paper innovatively puts forward the application of the artificial ground freezing(AGF)method at the end of the curing period of cast-in-place piles in permafrost.A field test on the AGF was conducted at the Beiluhe Observation and Research Station of Frozen Soil Engineering and Environment(34°51.2'N,92°56.4'E)in the Qinghai Tibet Plateau(QTP),and then a 3-D numerical model was established to investigate the thermal performance of piles using AGF under different engineering conditions.Additionally,the long-term thermal performance of piles after the completion of AGF under different conditions was estimated.Field experiment results demonstrate that AGF is an effective method to reduce the refreezing time of the soil surrounding the piles constructed in permafrost terrain,with the ability to reduce the pile-soil interface temperatures to below the natural ground temperature within 3 days.Numerical results further prove that AGF still has a good cooling effect even under unfavorable engineering conditions such as high pouring temperature,large pile diameter,and large pile length.Consequently,the application of this method is meaningful to save the subsequent latency time and solve the problem of thermal disturbance in pile construction in permafrost.The research results are highly relevant for the spread of AGF technology and the rapid building of pile foundations in permafrost.

关键词： Permafrost engineering Cast-in-place pile Artificial ground freezing Thermal performance.

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The hydrothermal changes of permafrost active layer and their impact on summer rainfall-runoff processes in an alpine meadow watershed,northwest China

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Research in Cold and Arid Regions 2022年第6期14卷 361-369页

作者： Jia Qin YongJian Ding TianDing Han YaPing Chang FaXiang Shi yanhui you State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Eco-hydrology Inland River Basin Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China

The freezing-thawing variation of permafrost active layer increases the complexity of rainfall-runoff processes in alpine river basins,Northwest China.And alpine meadow is the prominent ecosystem in these basins.This study selected a small alpine meadow watershed in the upper reaches of the Shule River Basin,China.We investigated alpine rainfall-runoff processes,as well as impacts of summer thaw depth of active layer,soil temperature and moisture variation on streamflow based on in-situ observations from July 2015 to December 2020.Some hydrologic parameters or indices were calculated using statistical methods,and impacts of permafrost change on river runoff were assessed using the variable infiltration capacity model(VIC).In the alpine meadow,surface soil(0–10 cm depth)of the active layer starts to freeze in mid-October each year,and begins to thaw in early April.Also,the deeper soil(70–80 cm depth)of the active layer starts to freeze in late October,and begins to thaw in late June.Moisture content in shallow soils fluctuates regularly,whereas deeper soils are more stable,and their response to rainstorms is negligible.During active layer thawing,the moisture content increases with soil depth.In the alpine meadow,vertical infiltration only occurred in soils up to 40 cm deep,and lateral flow occurred in0–20 and 60–80 cm deep soils at current rainfall intensity.Summer runoff ratios were 0.06–0.31,and runoff floods show lags of 9.5–23.0 h following the rainfall event in the study area.The freeze–thaw process also significantly impacts runoff regression coefficients,which were 0.0088–0.0654 per hour.Recession coefficient decrease negatively correlates with active layer thawing depth in summer and autumn.Alpine river basin permafrost can effectively increase peak discharge and reduce low flow.These findings are highly significant for rainfall–runoff conversion research in alpine areas of inland rivers.

关键词： Rainfall-runoff process Alpine meadow Permafrost active layer Northwest China

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The changing process and trend of ground temperature around tower foundations of Qinghai-Tibet Power Transmission line

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Research in Cold and Arid Regions 2019年第1期11卷 13-20页

作者： YanLi Xie QiHao Yu yanhui you ZhongQiu Zhang TingTao Gou State Grid Qinghai Electric Power Research Institute State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-environment and Resources Chinese Academy of Sciences

After the construction of Qinghai-Tibet Highway and Railway, the Qinghai-Tibet Power Transmission(QTPT) line is another major permafrost engineering project with new types of engineering structures. The changing process and trend of ground temperature around tower foundations are crucial for the stability of QTPT. We analyzed the change characteristics and tendencies of the ground temperature based on field monitoring data from 2010 to 2014. The results reveal that soil around the tower foundations froze and connected with the artificial permafrost induced during the construction of footings after the first freezing period, and the soil below the original permafrost table kept freezing in subsequent thawing periods. The ground temperature lowered to that of natural fields, fast or slowly for tower foundations with thermosyphons,while for tower foundations without thermosyphons, the increase in ground temperature resulted in higher temperature than that of natural fields. Also, the permafrost temperature and ice content are significant factors that influence the ground temperature around tower foundations. Specifically, the ground temperature around tower foundations in warm and ice-rich permafrost regions decreased slowly, while that in cold and ice poor permafrost regions cooled faster. Moreover, foundations types impacted the ground temperature, which consisted of different technical processes during construction and variant of tower footing structures. The revealed changing process and trend of the ground temperature is beneficial for evaluating the thermal regime evolution around tower foundations in the context of climate change.

关键词： Qinghai-Tibet Power Transmission line tower foundation ground temperature change characteristic trend

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运营期纵连板式无砟轨道端刺结构位移特征

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铁道工程学报 2024年第1期41卷 20-25页

作者：蔡小培王昌昌董博钟阳龙郑新国游彦辉北京交通大学北京100044 中国铁道科学研究院集团有限公司北京100081

研究目的:Π型端刺锚固体系是纵连板式无砟轨道路桥过渡段限制轨道结构位移的关键部位。本文考虑轨道结构与桥梁及摩擦板、端刺与土体的非线性相互作用关系,建立轨道-桥梁-路基-端刺结构一体化计算模型,研究锚固结构服役状态下的位移特... 详细信息

研究目的:Π型端刺锚固体系是纵连板式无砟轨道路桥过渡段限制轨道结构位移的关键部位。本文考虑轨道结构与桥梁及摩擦板、端刺与土体的非线性相互作用关系,建立轨道-桥梁-路基-端刺结构一体化计算模型,研究锚固结构服役状态下的位移特征,分析端刺与路基不同脱空位置对结构位移的影响,提出注浆填补层间脱空的增强方案,并对其可行性进行论证。研究结论:(1)端刺与路基完全脱空后,纵向位移相比脱空前大幅增加且超过了3 mm位移限值,脱空引起的路基对端刺结构摩阻力、锚固力下降会导致端刺产生超量位移;(2)摩擦板区域的脱空对端刺位移影响很小,主端刺区域脱空和完全脱空引起的端刺纵向位移只相差0.11 mm,所以主端刺区域路基脱空是引发结构超量位移的主因;(3)采用注浆方式对脱空区域路基进行加固整治后端刺的纵向位移降低了3.5 mm左右,端刺结构位移恢复到了与正常服役状况相近的程度;(4)本研究成果可为现场Π型端刺结构超量位移整治提供一定的理论依据。

关键词：路桥过渡段 Π型端刺脱空超量位移注浆增强

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Numerical analysis of applying special pavements to solve the frost heave diseases of high-speed railway roadbeds in seasonally frozen ground regions

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Research in Cold and Arid Regions 2015年第4期7卷 340-347页

作者： Chang Yuan FuJun Niu QiHao Yu XinBin Wang Lei Guo yanhui you State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research InstituteCAS University of Chinese Academy of Sciences

The Haerbin-Dalian Passenger Dedicated Line is the first high-speed railway constructed in the seasonally frozen ground regions of northeastern China. Frost heave diseases occurred in the first winter of its operation （between October 2012 and January 2013）, and frost heave was observed mainly in the roadbed fills that were considered not susceptible to frost heave. This paper proposes applying two special pavements -- black pavement and insulation-black pavement -- to improve the thermal regime of the roadbed. Three numerical models of the roadbed temperature field were built based on the field con- ditions of the Changchun section （D3K692＋840 to D3K692＋860）. The results show that：（1） Compared with cement pave- ment, black pavement and insulation-black pavement could reduce the freezing index at the roadbed surface by 37% and 64%, respectively, which could influence the maximum frozen depth; （2） the maximum frozen depths under the black pavement and insulation-black pavement were respectively 1.3-1.4 m and 1 m. Compared with cement pavement, they could reduce the maximum frozen depth by 0.4 m and 0.7-0.8 m, respectively, which would reduce the permitted amount of frost heave by 4 mm and 7-8 ram, which would meet the deformation limit established by the Code for Design on Special Subgrade of Railway; （3） the freezing periods of the black pavement and the insulation-black pavement were, respectively, approximately four months and two months. Compared with cement pavement, they could reduce the freezing period by approximately 19 days and 40 days, respectively, and delay the initial freezing time by 9 days and 18 days; and （4） compared with cement pavement, black pavement and black-insulation pavement could reduce the frozen areas of roadbeds in the cold season, which suggests that these two special pavements could provide better thermal stability for roadbeds.

关键词： frost heave numerical simulation special pavement thermal regime

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高寒山区季节冻土冻融特征参数变化及其影响因素——以天山南坡为例

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冰川冻土 2024年第1期46卷 89-100页

作者：施发祥秦甲韩添丁崔峻豪丁永建成鹏游艳辉中国科学院西北生态环境资源研究院唐古拉山冰冻圈与环境西藏自治区野外科学观测研究站甘肃兰州730000 中国科学院西北生态环境资源研究院冰冻圈科学国家重点实验室甘肃兰州730000 中国科学院西北生态环境资源研究院冻土工程国家重点实验室甘肃兰州730000 中国科学院大学北京100049 新疆维吾尔自治区气象局新疆乌鲁木齐830002

季节冻土在高寒山区广泛分布,其冻融过程会对水文水资源和生态环境产生深刻影响。研究气候变化背景下高寒山区季节冻土冻融特征参数变化及影响机理,可为高寒山区水资源管理和生态保护提供科学依据。本文选择天山南坡作为研究区,基于13... 详细信息

季节冻土在高寒山区广泛分布,其冻融过程会对水文水资源和生态环境产生深刻影响。研究气候变化背景下高寒山区季节冻土冻融特征参数变化及影响机理,可为高寒山区水资源管理和生态保护提供科学依据。本文选择天山南坡作为研究区,基于13个气象站点1958年以来季节冻土冻融参数(最大冻深、冻结期、始冻日、解冻日)、气温、地表温度、降雨和积雪等数据,使用空间分析和多元线性回归统计等方法对冻融参数的时空变化特征进行分析,量化不同气候因素对季节冻土冻融变化的影响权重。结果表明,季节冻土最大冻深在(48.5±11.4)~(96.8±8.5)cm之间,冻结天数在(102±10)~(141±14)d之间,多年平均始冻日在11月7日至19日之间,多年平均解冻日在3月1日至28日之间。1950年代至2010年代期间,始冻日逐渐推迟,解冻日逐渐提前,冻结天数缩短。空间分布上,最大冻深有“海拔高,最大冻深大”的规律;空间变化趋势上,最大冻深在研究区中部显著增加;冻结天数在研究区内大范围显著缩短。季节冻土冻融变化与气温相关性最强,温度(气温和地表温度)是季节冻土冻融变化的主导因子。定量评价发现,气温影响占比(24.1±3.6)%,地表温度影响占比(12.1±3.1)%,降雨影响占比(9.6±1.7)%,积雪影响占比(5.1±1.5)%。

关键词：季节冻土最大冻深冻结期时空变化天山南坡

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Problems and countermeasures in construction of transmission line projects in permafrost regions

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Research in Cold and Arid Regions 2014年第5期6卷 432-439页

作者： GuoShang Wang QiHao Yu yanhui you Ze Zhang Lei Guo ShiJun Wang Yong Yu Gansu Electric Power Design Institute State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences Gansu Power Transmission Transformation Company

Construction of power transmission lines is becoming an important part of permafrost engineering in China.This paper reviews the construction status and problems of transmission lines in different countries,as well as corresponding solutions that would be of practical significance for sustainable engineering practices.Russia has the longest history of transmission line construction in permafrost areas,with transmission lines（mainly 220 kV and 500 kV） spanning approximately 100,000 km.However,all countries suffer from permafrost-related tower foundation stability problems caused by freezing-thawing hazards such as frost heave and thaw settlement,frost lifting,and harmful cryogenic phenomena.As point-line transmission line constructions,the lines,poles and towers should be reasonably selected and installed with a comprehensive consideration of frozen soil characteristics to effectively reduce the occurrence of freezing-thawing disasters.Reinforced concrete pile foundations are widely used in the permafrost regions,and construction in winter is also a universal practice.Moreover,facilitating engineering measures like thermosyphons are an effective way to reduce freezing-thawing hazards and to maintain the stability of tower foundations.

关键词： permafrost transmission line key issues analysis

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Mountain permafrost distribution modeling using Multivariate Adaptive Regression Spline (MARS) in the Wenquan area over the Qinghai-Tibet Plateau

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Research in Cold and Arid Regions 2012年第5期4卷 361-370页

作者： XiuMin Zhang ZhuoTong Nan JiChun Wu ErJi Du Tong Wang yanhui you State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China CoM and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China

In high mountainous areas, the development and distribution of alpine permafrost is greatly affected by macro- and mi- cro-topographic factors. The effects of latitude, altitude, slope, and aspect on the distribution of permafrost were studied to under- stand the dislribution patterns of permafrost in Wenquan on the Qinghai-Tibet Plateau. Cluster and correlation analysis were per- formed based on 30 m Global Digital Elevation Model （GDEM） data and field data obtained using geophysical exploration and borehole drilling methods. A Multivariate Adaptive Regression Spline model （MARS） was developed to simulate permafrost spa- tial distribution over the studied area. A validation was followed by comparing to 201 geophysical exploration sites, as well as by comparing to two other models, i.e., a binary logistic regression model and the Mean Annual Ground Temperature model （IVlAGT）. The MARS model provides a better simulation than the other two models. Besides the control effect of elevation on permafrost distribution, the MARS model also takes into account the impact of direct solar radiation on permafrost distribution.

关键词： permafrost distribution model Multivariate Adaptive Regression Splines Qinghai-Tibet Plateau permafrost

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Lactate:a prospective target for therapeutic intervention in psychiatric disease

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Neural Regeneration Research 2024年第7期19卷 1473-1479页

作者： yanhui Cai Haiyun Guo Tianle Han Huaning Wang Department of Psychiatry Xijing HospitalFourth Military Medical UniversityXi’anShaanxi ProvinceChina Department of Anesthesiology and Perioperative Medicine Xijing HospitalFourth Military Medical UniversityXi’anShaanxi ProvinceChina

Although antipsychotics that act via monoaminergic neurotransmitter modulation have considera ble therapeutic effect,they cannot completely relieve clinical symptoms in patients suffering from psychiatric disorde rs.This may be attributed to the limited range of neurotransmitters that are regulated by psychotropic drugs.Recent findings indicate the need for investigation of psychotropic medications that target less-studied neurotransmitte rs.Among these candidate neurotransmitters,lactate is developing from being a waste metabolite to a glial-neuronal signaling molecule in recent years.Previous studies have suggested that cerebral lactate levels change considerably in numerous psychiatric illnesses;animal experiments have also shown that the supply of exogenous la ctate exerts an antidepressant effect.In this review,we have described how medications targeting newer neurotransmitte rs offer promise in psychiatric diseases;we have also summarized the advances in the use of lactate(and its corresponding signaling pathways)as a signaling molecule.In addition,we have described the alterations in brain lactate levels in depression,anxiety,bipolar disorder,and schizophrenia and have indicated the challenges that need to be overcome before brain lactate can be used as a therapeutic target in psychopharmacology.

关键词： antidepressant anxiety bipolar disorder depression lactate psychiatric disease psychopharmacology schizophrenia signal molecular therapeutics

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Influence of Kerr Effect on Second-Order Nonlinearity Induced Transparency

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Wuhan University Journal of Natural Sciences 2024年第1期29卷 67-73页

作者： ZHANG Zhiqiang ZHOU yanhui College of Architectural Engineering Zhengzhou Business UniversityZhengzhou 451200HenanChina Quantum Information Research Center Shangrao Normal UniversityShangrao 334001JiangxiChina

We theoretically study the effect of Kerr effect on the second-order nonlinearity induced transparency in a double-resonant optical cavity system.We show that in the presence of the Kerr effect,as the strength of the Kerr effect increases,the absorption curve exhibits an asymmetric-symmetric-asymmetric transition,and the zero absorption point shifts with the increase of the Kerr effect.Furthermore,by changing the strength of the Kerr effect,we can control the width of the transparent window,and the position of the zero-absorption point and meanwhile change the left and right width of the absorption peak.The asymmetry absorption curve can be employed to improve the quality factor of the cavity when the frequency detuning is tuned to be around the right peak.The simple dependence of the zeroabsorption point on the strength of Kerr effect suggests that the strength of Kerr effect can be measured by measuring the position of the zero-absorption point in a possible application.

关键词： Kerr effect second-order nonlinearity induced transparency nonlinear optics quantum optics

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