Spatial distribution of supra-permafrost groundwater in the Qinghai-Tibet Engineering Corridor using inversion models

Supra-permafrost groundwater(SPG)is a key factor that causes damage to highways and railways in the Qinghai-Tibet Engineering Corridor(QTEC).It is difficult to monitor SPG in the field due to their complex formation mechanisms and movement characteristics.Traditional single-site field monitoring studies limit the spatial and temporal precision of SPG spatial distribution.To determine the moisture content of shallow soils and the SPG distribution along the QTEC,this work employed the temperature vegetation dryness index and remote sensing models for groundwater table distribution models.The accuracies of the models were validated using mea-surements obtained from different sites in the corridor.In the permafrost zones of the QTEC,72%,22%and 6%of the SPG were located at depths of 0.5-1,<0.5 and>1 m,respectively.Meanwhile,79.4%of the area along the Qinghai-Tibet Highway(QTH)(Xidatan-Tanggula)section contained SPG.In these sections with SPG,37.9%have an SPG table at depths of 0.5-0.8 m.This study preliminarily explored the SPG distribution in the QTEC with a 30 m resolution.The findings can help improve the spatial scale of SPG research,provide a basis for the analysis of the hydrothermal mechanisms,and serve as a guide in the assessment of operational risks and road structure designs.

Geological risk assessment of traffic engineering construction among 7.0-8.5 magnitude earthquake areas:Practice from the Sichuan-Tibet transport corridor in the eastern Tibetan Plateau

At least 13 active fault zones have developed in the Ya'an-Linzhi section of the Sichuan-Tibet transport corridor,and there have been undergone 17 MS≥7.0 earthquakes,the largest earthquake is 1950 Chayu MS 8.5 earthquake,which has very strong seismic activity.Therefore,carrying out engineering construction in the Sichuan-Tibet transport corridor is a huge challenge for geological technological personnel.To determining the spatial geometric distribution,activity of active faults and geological safety risk in the Sichuan-Tibet transport corridor.Based on remote sensing images,ground surveys,and chronological tests,as well as the deep geophysical and current GPS data,we investigated the geometry,segmentation,and paleoearthquake history of five major active fault zones in the Ya'an-Linzhi section of the Sichuan-Tibet transport corridor,namely the Xianshuihe,Litang,Batang,Jiali-Chayu and Lulang-Yigong.The five major fault zones are all Holocene active faults,which contain strike-slip components as well as thrust or normal fault components,and contain multiple branch faults.The Selaha-Kangding segment of the Xianshuihe fault zone,the Maoyaba and Litang segment of the Litang fault zone,the middle segment(Yigong-Tongmai-Bomi)of Jiali-Chayu fault zone and Lulang-Yigong fault zone have the risk of experiencing strong earthquakes in the future,with a high possibility of the occurrence of MS≥7.0 earthquakes.The Jinsha River and the Palong-Zangbu River,which is a high-risk area for geological hazard chain risk in the Ya'an-Linzhi section of the Sichuan-Tibet transport corridor.Construction and safe operation Ya'an-Linzhi section of the Sichuan-Tibet transport corridor,need strengthen analysis the current crustal deformation,stress distribution and fault activity patterns,clarify active faults relationship with large earthquakes,and determine the potential maximum magnitude,epicenters,and risk range.This study provides basic data for understanding the activity,seismicity,and tectonic deformation patterns of the regional faults in the Sichuan-Tibet transport corridor.

Characteristics and changes of permafrost along the engineering corridor of National Highway 214 in the eastern Qinghai-Tibet Plateau

Due to a series of linear projects built along National Highway 214,the second"Permafrost Engineering Corridor"on the Qinghai-Tibet Plateau has formed.In this paper,by overcoming the problems of data decentralization and standard inconsistency,permafrost characteristics and changes along the engineering corridor are systematically summarized based on the survey and monitoring data.The results show that:1)Being controlled by elevation,the permafrost is distributed in flake discontinuity with mountains as the center along the line.The total length of the road section in permafrost regions is 365 km,of which the total length of the permafrost section of National Highway 214 is 216.7 km,and the total length of the permafrost section of Gong-Yu Expressway is 197.3 km.The mean annual ground temperature(MAGT)is higher than−1.5℃,and permafrost with MAGT lower than−1.5℃ is only distributed in the sections at Bayan Har Mountain and E'la Mountain.There are obvious differences in the distribution of ground ice in the different sections along the engineering corridor.The sections with high ice content are mainly located in Zuimatan,Duogerong Plain and the top of north and south slope of Bayan Har Mountain.The permafrost thickness is controlled by the ground temperature,and permafrost thickness increases with the decrease of the ground temperature,with the change rate of about 37 m/℃.2)Local factors(topography,landform,vegetation and lithology)affect the degradation process of permafrost,and then affect the distribution,ground temperature,thickness and ice content of permafrost.Asphalt pavement has greatly changed the heat exchange balance of the original ground,resulting in serious degradation of the permafrost.Due to the influence of roadbed direction trend,the phenomenon of shady-sunny slope is very significant in most sections along the line.The warming range of permafrost under the roadbed is gradually smaller with the increase of depth,so the thawing settlement of the shallow section with high ice-content permafrost is more significant.

Potential seismic landslide hazard and engineering effect in the Ya’an-Linzhi section of the Sichuan-Tibet transportation corridor, China

The Sichuan-Tibet transportation corridor is located at the eastern margin of the Qinghai-Tibet Plateau,where the complex topography and geological conditions,developed geo-hazards have severely restricted the planning and construction of major projects.For the long-term prevention and early control of regional seismic landslides,based on analyzing seismic landslide characteristics,the Newmark model was used to carry out the potential seismic landslide hazard assessment with a 50-year beyond probability 10%.The results show that the high seismic landslide hazard is mainly distributed along large active tectonic belts and deep-cut river canyons,and are significantly affected by the active tectonics.The low seismic landslide hazard is mainly distributed in the flat terrain such as the Quaternary basins,broad river valleys,and plateau planation planes.The major east-west linear projects mainly pass through five areas with high seismic landslide hazard:Luding-Kangding section,Yajiang-Xinlong(Yalong river)section,Batang-Baiyu(Jinsha river)section,Basu(Nujiang river)section,and Bomi-Linzhi(eastern Himalaya syntaxis)section.The seismic action of the Bomi-Linzhi section can also induce high-risk geo-hazard chains such as the high-level glacial lake breaks and glacial debris flows.The early prevention of seismic landslides should be strengthened in the areas with high seismic landslide hazard.

Applying the AHP-FUZZY method to evaluate the measure effect of rubble roadbed engineering in permafrost regions of Qinghai-Tibet Plateau: a case study of Chaidaer-Muli Railway

This article attempts to investigate the measure effect of rubble roadbed engineering in permafrost regions of Qinghai-Tibet Plateau. As a case study, Chaidaer-Muli Railway is used to evaluate the measure effect of rubble roadbed engineering in permafrost regions. The AHP(Analytic Hierarchy Process) method is thus employed to establish the evaluation indicator system. The evaluation factor is selected by analyzing the mutual relation between the permafrost environment and roadbed engineering. Thus, a hierarchical structure model is established based on the selected evaluation indices. Each factor is weighted to determine the status in the evaluation system, and grading standards are built for providing a basis for the evaluation. Then, the fuzzy mathematical method is introduced to evaluate the measure effect of rubble roadbed engineering in permafrost regions along the Chadaer-Muli Railway. Results show that most of the permafrost roadbed is in a preferable condition(b) along the Chaidaer-Muli Railway due to rubble engineering measures. This proportion reaches to 86.1%. The proportion in good(a), general(c) and poor states(d) are 0.0%, 7.5% and 6.4%, respectively, in all the evaluation sections along the Chaidaer-Muli Railway. Ground-temperature monitoring results are generally consistent with AHP-FUZZY evaluation results. This means that the AHP-FUZZY method can be applied to evaluate the effect of rubble roadbed engineering measures in permafrost regions. The effect evaluation of engineering measures will provide timely and effective feedback information for further engineering design. The series of engineering measures will more effectively protect permafrost stability.

Analysis of the Theoretical Foundation and Engineering Effect for Air-duct Embankment on the Qinghai-Tibet Railway

Based on the corresponding theories of engineering thermodynamics and hydro-dynamics, a careful study is made of the characteristics of air flow in different duct-embedded ways. According to critical Reynolds number, the atmospheric critical velocity of the duct with different diameters, which makes laminar flow different from turbulent flow, is calculated. Given the condition in which a forced flow occurs and the wind strength is larger than the atmospheric pressure gradient along the air-duct, a rational ratio of the length to the diameter is presented. Based on the above theory and field test data on soil temperature and embankment settlement, the advantages and disadvantages are discussed in details of all duct-embedded ways that might affect the stability of embankment.

Dynamic response of mountain tunnel,bridge,and embankment along the Sichuan-Tibet transportation corridor to active fault based on model tests

The Sichuan-Tibet transportation corridor is prone to numerous active faults and frequent strong earthquakes.While extensive studies have individually explored the effect of active faults and strong earthquakes on different engineering structures,their combined effect remains unclear.This research employed multiple physical model tests to investigate the dynamic response of various engineering structures,including tunnels,bridges,and embankments,under the simultaneous influence of cumulative earthquakes and stick-slip misalignment of an active fault.The prototype selected for this study was the Kanding No.2 tunnel,which crosses the Yunongxi fault zone within the Sichuan-Tibet transportation corridor.The results demonstrated that the tunnel,bridge,and embankment exhibited amplification in response to the input seismic wave,with the amplification effect gradually decreasing as the input peak ground acceleration(PGA)increased.The PGAs of different engineering structures were weakened by the fault rupture zone.Nevertheless,the misalignment of the active fault may decrease the overall stiffness of the engineering structure,leading to more severe damage,with a small contribution from seismic vibration.Additionally,the seismic vibration effect might be enlarged with the height of the engineering structure,and the tunnel is supposed to have a smaller PGA and lower dynamic earth pressure compared to bridges and embankments in strong earthquake zones crossing active faults.The findings contribute valuable insights for evaluating the dynamic response of various engineering structures crossing an active fault and provide an experimental reference for secure engineering design in the challenging conditions of the Sichuan-Tibet transportation corridor.

Identification and distribution of 13003 landslides in the northwest margin of Qinghai-Tibet Plateau based on human-computer interaction remote sensing interpretation

The periphery of the Qinghai-Tibet Plateau is renowned for its susceptibility to landslides.However,the northwestern margin of this region,characterised by limited human activities and challenging transportation,remains insufficiently explored concerning landslide occurrence and dispersion.With the planning and construction of the Xinjiang-Tibet Railway,a comprehensive investigation into disastrous landslides in this area is essential for effective disaster preparedness and mitigation strategies.By using the human-computer interaction interpretation approach,the authors established a landslide database encompassing 13003 landslides,collectively spanning an area of 3351.24 km^(2)(36°N-40°N,73°E-78°E).The database incorporates diverse topographical and environmental parameters,including regional elevation,slope angle,slope aspect,distance to faults,distance to roads,distance to rivers,annual precipitation,and stratum.The statistical characteristics of number and area of landslides,landslide number density(LND),and landslide area percentage(LAP)are analyzed.The authors found that a predominant concentration of landslide origins within high slope angle regions,with the highest incidence observed in intervals characterised by average slopes of 20°to 30°,maximum slope angle above 80°,along with orientations towards the north(N),northeast(NE),and southwest(SW).Additionally,elevations above 4.5 km,distance to rivers below 1 km,rainfall between 20-30 mm and 30-40 mm emerge as particularly susceptible to landslide development.The study area’s geological composition primarily comprises Mesozoic and Upper Paleozoic outcrops.Both fault and human engineering activities have different degrees of influence on landslide development.Furthermore,the significance of the landslide database,the relationship between landslide distribution and environmental factors,and the geometric and morphological characteristics of landslides are discussed.The landslide H/L ratios in the study area are mainly concentrated between 0.4 and 0.64.It means the landslides mobility in the region is relatively low,and the authors speculate that landslides in this region more possibly triggered by earthquakes or located in meizoseismal area.

Characteristics of groundwater in Northeast Qinghai-Tibet Plateau and its response to climate change and human activities:A case study of Delingha,Qaidam Basin

Delingha is located in the northeast margin of Qaidam Basin.Bayin River alluvial proluvial fan is the main aquifer of Delingha,in which groundwater generally flows from north to south.The hydrochemistry results showed that two different hydrochemical evolution paths formed along southeast and southwest directions,respectively.Cl-Na type groundwater was formed in front of Gahai Lake,and SO_(4)·HCO_(3)-Na·Ca type groundwater was formed in front of Keluke Lake.The results of deuterium(D)and 18O revealed that the groundwater mainly originated from the continuous accumulation of precipitation during geological history under cold and humid climate conditions.In addition,results of ^(14)C indicated that the groundwater age was more than 1140 years,implying relatively poor renewal capability of regional groundwater.Moreover,our numerical modeling results showed that the regional groundwater level will continue to rise under the warm and humid climate conditions.

Growth behavior and resource potential evaluation of gas hydrate in core fractures in Qilian Mountain permafrost area, Qinghai-Tibet Plateau

The Qilian Mountain permafrost area located in the northern of Qinghai-Tibet Plateau is a favorable place for natural gas hydrate formation and enrichment,due to its well-developed fractures and abundant gas sources.Understanding the formation and distribution of multi-component gas hydrates in fractures is crucial in accurately evaluating the hydrate reservoir resources in this area.The hydrate formation experiments were carried out using the core samples drilled from hydrate-bearing sediments in Qilian Mountain permafrost area and the multi-component gas with similar composition to natural gas hydrates in Qilian Mountain permafrost area.The formation and distribution characteristics of multi-component gas hydrates in core samples were observed in situ by X-ray Computed Tomography(X-CT)under high pressure and low temperature conditions.Results show that hydrates are mainly formed and distributed in the fractures with good connectivity.The ratios of volume of hydrates formed in fractures to the volume of fractures are about 96.8%and 60.67%in two different core samples.This indicates that the fracture surface may act as a favorable reaction site for hydrate formation in core samples.Based on the field geological data and the experimental results,it is preliminarily estimated that the inventory of methane stored in the fractured gas hydrate in Qilian Mountain permafrost area is about 8.67×1013 m3,with a resource abundance of 8.67×108 m3/km2.This study demonstrates the great resource potential of fractured gas hydrate and also provides a new way to further understand the prospect of natural gas hydrate and other oil and gas resources in Qilian Mountain permafrost area.

Microplastic contamination in lacustrine sediments in the Qinghai-Tibet Plateau:Current status and transfer mechanisms

This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau.The study surveyed the average abundance of microplastics in sediments.The abundance of microplastics in sediments of lakes from the Qinghai-Tibet Plateau is 17.22-2643.65 items/kg DW and 0-60.63 items/kg DW based on the data of the Qinghai Lake and the Siying Co Basin.The microplastic abundance in sediments from small and medium lakes is very high compared to that in other areas in the world.Like microplastics in other lakes of the world,those in the lakes in the Qinghai-Tibet Plateau mainly include organic polymers PA,PET,PE,and PP and are primarily in the shape of fibers and fragments.The microplastic pollution of lacustrine sediments in the Qinghai-Tibet Plateau is affected by natural changes and by human activities,and the concentration of microplastics in lacustrine ecosystems gradually increases through food chains.Furthermore,the paper suggests the relevant administrative departments of the Qinghai-Tibet Plateau strengthen waste management while developing tourism and pay much attention to the impacts of microplastics in water environments.This study provides a reference for preventing and controlling microplastic contamination in the Qinghai-Tibet Plateau.

Identification of Sustainability Indicators and Evaluation of Transportation Corridors during Construction Using Fuzzy VIKOR Method

Sustainability is popularly defined as meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. Social, economic and environmental parameters are most commonly accepted as the three pillars of sustainability. In this paper, various sustainability indicators have been identified during the construction stage for elevated transportation corridors and thereafter classified under various categories. Using fuzzy VIKOR technique, sustainability evaluation of transportation corridors is made on two selected project sites of two different government organizations using various identified sustainability indicators, i.e., a 3.2-km long elevated road project under construction from Vikaspuri to Meerabagh in West Delhi by PWD （Public Works Department） and the metro rail elevated corridor （part） from Punjabi Bagh to Mayapuri as a part of Phase 3, Line 7 by DMRC （Delhi Metro Rail Corporation）. The study is made at both sites in the midst of the construction period and it is identified that during the construction stage, the sustainability of these transportation corridors is just not limited to three pillars, but in actuality, it is much beyond that. From the study, it is inferred that the metro rail elevated corridor is a more sustainable corridor, in the context of the identified sustainability indicators.

Change trend of natural gas hydrates in permafrost on the Qinghai-Tibet Plateau(1960-2050)under the background of global warming and their impacts on carbon emissions

Global warming and the response to it have become a topic of concern in today’s society and are also a research focus in the global scientific community.As the world’s third pole,the global warming amplifier,and the starting region of China’s climate change,the Qinghai-Tibet Plateau is extremely sensitive to climate change.The permafrost on the Qinghai-Tibet Plateau is rich in natural gas hydrates(NGHs)resources.Under the background of global warming,whether the NGHs will be disassociated and enter the atmosphere as the air temperature rises has become a major concern of both the public and the scientific community.Given this,this study reviewed the trend of global warming and accordingly summarized the characteristics of the temperature increase in the Qinghai-Tibet Plateau.Based on this as well as the distribution characteristics of the NGHs in the permafrost on the Qinghai-Tibet Plateau,this study investigated the changes in the response of the NGHs to global warming,aiming to clarify the impacts of global warming on the NGHs in the permafrost of the plateau.A noticeable response to global warming has been observed in the Qinghai-Tibet Plateau.Over the past decades,the increase in the mean annual air temperature of the plateau was increasingly high and more recently.Specifically,the mean annual air temperature of the plateau changed at a rate of approximately 0.308-0.420℃/10a and increased by approximately 1.54-2.10℃in the past decades.Moreover,the annual mean ground temperature of the shallow permafrost on the plateau increased by approximately 1.155-1.575℃and the permafrost area decreased by approximately 0.34×10^(6)km^(2) from about 1.4×10^(6)km^(2) to 1.06×10^(6)km^(2) in the past decades.As indicated by simulated calculation results,the thickness of the NGH-bearing permafrost on the Qinghai-Tibet Plateau has decreased by 29-39 m in the past 50 years,with the equivalent of(1.69-2.27)×10^(10)-(1.12-1.51)×10^(12)m^(3) of methane(CH_(4))being released due to NGHs dissociation.It is predicted that the thickness of the NGH-bearing permafrost will decrease by 23 m and 27 m,and dissociated and released NGHs will be the equivalent of(1.34-88.8)×10^(10)m^(3) and(1.57-104)×10^(10)m^(3)of CH_(4),respectively by 2030 and 2050.Considering the positive feedback mechanism of NGHs on global warming and the fact that CH_(4) has a higher greenhouse effect than carbon dioxide,the NGHs in the permafrost on the Qinghai-Tibet Plateau will emit more CH_(4) into the atmosphere,which is an important trend of NGHs under the background of global warming.Therefore,the NGHs are destructive as a time bomb and may lead to a waste of efforts that mankind has made in carbon emission reduction and carbon neutrality.Accordingly,this study suggests that human beings should make more efforts to conduct the exploration and exploitation of the NGHs in the permafrost of the Qinghai-Tibet Plateau,accelerate research on the techniques and equipment for NGHs extraction,storage,and transportation,and exploit the permafrost-associated NGHs while thawing them.The purpose is to reduce carbon emissions into the atmosphere and mitigate the atmospheric greenhouse effect,thus contributing to the global goal of peak carbon dioxide emissions and carbon neutrality.

Experimental and numerical interpretation on composite foundation consisting of soil-cement column within warm and ice-rich frozen soil

Affected by climate warming and anthropogenic disturbances, the thermo-mechanical stability of warm and ice-rich frozen ground along the Qinghai-Tibet engineering corridor(QTEC) is continuously decreased, which may delay the construction of major projects in the future. In this study, based on chemical stabilization of warm and icerich frozen ground, the soil-cement column(SCC) for ground improvement was recommended to reinforce the foundations in warm and ice-rich permafrost regions. To explore the validity of countermeasures mentioned above, both the original foundation and the composite foundation consisting of SCC with soil temperature of -1.0℃ were prepared in the laboratory, and then the plate loading tests were carried out. The laboratory investigations indicated that the bearing capacity of composite foundation consisting of SCC was higher than that of original foundation, and the total deformation of original foundation was greater than that of composite foundation, meaning that overall stability of foundation with warm and ice-rich frozen soil can be improved by SCC installation. Meanwhile, a numerical model considering the interface interaction between frozen soil and SCC was established for interpretating the bearing mechanism of composite foundation. The numerical investigations revealed that the SCC within composite foundation was responsible for the more applied load, and the applied load can be delivered to deeper zone in depth due to the SCC installation, which was favorable for improving the bearing characteristic of composite foundation. The investigations provide the valuable guideline for the choice of engineering supporting techniques to major projects within the QTEC.

川西藏东交通廊道区域工程地质条件评价

区域工程地质条件是重大工程规划建设地质安全的重要保障。川西藏东交通廊道位于青藏高原东部,穿越世界上地形地貌和地质构造最复杂的地区,区域工程地质环境复杂。响应重大工程规划建设的地质安全需求,以川西藏东交通廊道重大线性工程沿线为研究区,在分析区域工程地质环境的基础上,选取9个地质环境因子指标,采用基于GIS的层次分析法,完成了区域工程地质条件评价,将研究区划分为工程地质条件好、较好、中等和差4个等级。结果显示,活动断裂是最不利的工程地质条件因素,其次是地形起伏度和地质灾害易发程度。工程地质条件好的地区远离活动断裂带和深切峡谷,呈块状、条带状分布于活动断裂带及深切峡谷之间。工程地质条件差的地区主要分布于活动断裂带和高山峡谷区,突出表现为距活动断裂较近,尤其是多条断裂相交或近于相交的地区。研究结果能够为川西藏东交通廊道重大工程规划建设地质安全提供科学支撑。

Study on the atmospheric heat engine efficiency and heat source characteristics of the Qinghai-Tibet Plateau in summer

There are many types of atmospheric heat engines in land-air systems.The accurate definition,calculation and interpretation of the efficiency of atmospheric heat engines are key to understanding energy transfer and transformation of landair systems.The atmosphere over the Qinghai-Tibet Plateau(QTP)in summer can be regarded as a positive heat engine.The study of the heat engine efficiency is helpful to better understand land-air interaction and thermal-dynamic processes on the QTP.It also provides a new perspective to explain the impact of the QTP on the climate of China,East Asia and even the world.In this paper,we used MOD08 and ERA5 reanalysis data to calculate the atmospheric heat engine efficiency,surface heat source and atmospheric heat source on the QTP in summer(May to September)from 2000 to 2020.The average atmospheric heat engine efficiency on the QTP in summer from 2000 to 2020 varies between 1.2%and 1.5%,which is less than 1.6%;the heat engine efficiency in summer is higher than that in June,July and August;the Qaidam Basin is the region with the highest atmospheric heat engine efficiency,followed by the western QTP.The mean surface heat source on the QTP in summer from 2000 to 2020 is 96.0 W m^(−2),the atmospheric heat source is 90.7 W m^(−2),and the release of precipitation condensation latent heat is the most important component of the atmospheric heat source on the QTP in summer.There is a strong and significant positive correlation between the atmospheric heat engine efficiency and the surface heat source on the QTP in summer.The precipitation condensation latent heat is the most important component of the atmospheric heat source in summer and can reflect the precipitation process.There is a strong and significant negative correlation between the atmospheric heat engine efficiency and the atmospheric heat source on the QTP in summer.

Evaluation and prediction of engineering construction suitability in the Chinae-Mongoliae-Russia economic corridor

It is proposed to build a high-speed railway through the China‒Mongolia‒Russia economic corridor(CMREC)which runs from Beijing to Moscow via Mongolia.However,the frozen ground in this corridor has great impacts on the infrastructure stability,especially under the background of climate warming and permafrost degradation.Based on the Bayesian Network Model(BNM),this study evaluates the suitability for engineering construction in the CMREC,by using 21 factors in five aspects of terrain,climate,ecology,soil,and frozen-ground thermal stability.The results showed that the corridor of Mongolia's Gobi and Inner Mongolia in China is suitable for engineering construction,and the corridor in Amur,Russia near the northern part of Northeast China is also suitable due to cold and stable permafrost overlaying by a thin active layer.However,the corridor near Petropavlovsk in Kazakhstan and Omsk in Russia is not suitable for engineering construction because of low freezing index and ecological vulnerability.Furthermore,the sensitivity analysis of influence factors indicates that the thermal stability of frozen ground has the greatest impact on the suitability of engineering construction.These conclusions can provide a reference basis for the future engineering planning,construction and risk assessment.

地下综合管廊侧墙单侧支模施工工艺在受限空间中的应用实践

在城市建设过程中,某个单一的建设项目因建设时序原因,在建设过程中往往受到条件限制无法采取常规方式施工。地下综合管廊涉及基坑开挖,在结构施工中,随着板桩支护被广泛采用,地下综合管廊侧墙施工多受到既有条件限制,在结构混凝土施工中不得不采用单侧支模。但是单侧支模方式过程控制不当容易造成混凝土模板错峰、混凝土平整度差等,难以保证施工质量。该文通过在成都市天府新区福州路西段项目这一实际工程项目的运用进行案例研究,介绍在地铁正常运营线路外侧施工综合管廊工程单侧支模施工工艺的应用实践。通过对施工工艺的控制,分析墙体外观质量,提出解决措施并取得良好效果。

Study on ground temperature change and characteristic response of engineering geology of permafrost along Qinghai-Tibet Railway

Along with the global warming in the recent scores of years, comparatively big changes have taken place in the weather and other environmental conditions of the permafrost area in the Qinghai-Tibet Plateau, and very big changes have also occurred in the engineering geological conditions of the permafrost area. Based on a large volume of field survey data, this paper discusses the regularities of horizontal and vertical distribution of permafrost, with its focus of analysis on the temperature change characteristics of the soil in different frozen-soil zones, as well as presents simulation analysis and research for the engineering geologic characteristic response changes that would occur in the future when the temperature of the frozen soil in different zones rises by 1 and 2.6℃ respectively, which will have a tremendous impact on the stability of constructional work.

小区室外综合管廊给排水建设现状及优化对策

随着城市化进程的加快,小区室外综合管廊的建设成为了保障城市基础设施运行效率与安全的重要组成部分。本文分析了小区室外综合管廊给排水建设的当前现状及存在的问题,并以漳州市某项目为例,详细探讨了通过技术创新和管理优化来提升管廊系统性能的策略,旨在为类似项目提供可行的改进对策和参考。