A comprehensive review of lunar lava tube base construction and field research on a potential Earth test site

The Moon,as the closest celestial body to the Earth,plays a pivotal role in the progression of deep space exploration,and the establishment of research outposts on its surface represents a crucial step in this mission.Lunar lava tubes are special underground caves formed by volcanic eruptions and are considered as ideal natural shelters and scientific laboratories for lunar base construction.This paper begins with an in-depth overview of the geological origins,exploration history,and distribution locations of lunar lava tubes.Subsequently,it delves into the presentation of four distinctive advantages and typical concepts for constructing bases within lava tubes,summarizing the ground-based attempts made thus far in lunar lava tube base construction.Field studies conducted on a lava tube in Hainan revealed rock compositions similar to those found during the Apollo missions and clear lava tube structures,making it a promising analog site.Lastly,the challenges and opportunities encountered in the field of geotechnical engineering regarding the establishment of lunar lava tube bases are discussed,encompassing cave exploration technologies,in-situ testing methods,geomechanical properties under lunar extreme environments,base design and structural stability assessment,excavation and reinforcement techniques,and simulated Earth-based lava tube base.

Research on the Application of Intelligent Construction Technology in Hangzhouxi Railway Station

Relying on the construction management of Hangzhouxi Railway Station,this paper analyses the comprehensive application of intelligent construction technology and the establishment of the common data environment(CDE)by using BIM technology.This paper gives the idea that such issues are deeply explored as large-span curved surface structure improvement,steel structure construction monitoring,special-shaped ticket check canopy construction,prefabricated machine room construction,grid construction management,etc.so as to form an intelligent construction management system based on BIM technology.The system has achieved good application results in economic benefits,social benefits and environmental benefits,which can promote the gradual transformation to a more digitalized,networked and intelligent Hangzhouxi Railway Station,and lay a solid foundation for achieving the construction goals of controllable construction period,excellent quality,green and low carbon,etc.

Research on Site Planning of Mobile Communication Network

In this paper,considering the cost of base station,coverage,call quality,and other practical factors,a multi-objective optimal site planning scheme is proposed.Firstly,based on practical needs,mathematical modeling methods were used to establish mathematical expressions for the three sub-objectives of cost objectives,coverage objectives,and quality objectives.Then,a multi-objective optimization model was established by combining threshold and traffic volume constraints.In order to reduce the time complexity of optimization,a non-dominated sorting genetic algorithm(NSGA)is used to solve the multi-objective optimization problem of site planning.Finally,a strategy for clustering and optimizing weak coverage areas was proposed.In order to avoid redundant neighborhood retrieval during cluster expansion,the Fast Density-Based Spatial Clustering of Applications with Noise(FDBSCAN)clustering method was adopted.With different sub-objectives as the main objectives,this paper obtained the distribution map of weak coverage areas before and after the establishment of new base stations,as well as relevant site planning maps,and provided three planning schemes for different main objectives.The simulation results show that the traffic coverage of the three station planning schemes is above 90%.The change in the main optimization objective will result in a significant difference between the cost of the three solutions and the coverage of weak coverage points.

Planning and construction of Xiong’an New Area(city of over 5 million people):Contributions of China’s geologists and urban geology

China established Xiong’an New Area in Hebei Province in 2017,which is planned to accommodate about 5 million people,aiming to relieve Beijing City of the functions non-essential to its role as China’s capital and to expedite the coordinated development of the Beijing-Tianjin-Hebei region.From 2017 to 2021,the China Geological Survey(CGS)took the lead in multi-factor urban geological surveys involving space,resources,environments,and disasters according to the general requirements of“global vision,international standards,distinctive Chinese features,and future-oriented goals”in Xiong’an New Area,identifying the engineering geologic conditions and geologic environmental challenges of this area.The achievements also include a 3D engineering geological structure model for the whole area,along with“one city proper and five clusters”,insights into the ecology and the background endowment of natural resources like land,geothermal resources,groundwater,and wetland of the area before engineering construction,a comprehensive monitoring network of resources and environments in the area,and the“Transparent Xiong’an”geological information platform that is open,shared,dynamically updated,and three-dimensionally visualized.China’s geologists and urban geology have played a significant role in the urban planning and construction of Xiong’an New Area,providing whole-process geological solutions for urban planning,construction,operation and management.The future urban construction of Xiong’an New Area will necessitate the theoretical and technical support of earth system science(ESS)from various aspects,and the purpose is to enhance the resilience of the new type of city and to provide support for the green,low-carbon,and sustainable development of this area.

Influential Factors of House-purchasing Intention in Work construction Sites among Migrant Workers with a Case of Investigations on 203 Migrant Workers from Jiangxi Province

The research selected 13 factors from individual and family characters, construction site characters and work characters and analyzed the influences on the willingness of purchasing houses on construction sites with Logistic regression mod- el. The results showed that gender, age differences, personality, willingness on fami- ly land conversion, management of enterprises on construction sites, relatives and friends on construction lands, and Job satisfaction were approved by significant testing, but marital status, annual household income, the rate of migrant worker in a household, transportation in work city, and corporate reputation were not approved by significant testing.

Site Test of Thermal Environment of Rammed Earth Construction in Anji County of China

The scientific evaluation on heat insulation and preservation capacity of rammed earth construction can provide an effective evidence for its superiority in preserving thermal environment of the construction. By taking an eco-hotel in Zhejiang Anji County as the research object, 33 test points have been set. The indoor and outdoor air temperature of eco-hotel and the surface temperature of building envelopes had been recorded by using data acquisition instrument, temperature transmitter and other equipments from January 27 to February 2 in 2007. Then, the data of a period had been selected for comparison and analysis and the results had been obtained as follows. In January when the temperature difference between day and night in Anji was not large, without particular thermal insulation measures and equipments, the indoor temperature of eco-hotel fluctuated very little, showing that rammed earth construction was of obvious capacity for heat preservation and insulation, that its heat stability was evident and that it could ensure excellent indoor thermal environment.

Preliminary site classification of free-field strong motion stations based on Wenchuan earthquake records

During the great Wenchuan earthquake, about 460 permanent free-field stations in National Strong Motion Observation Network System （NSMONS） of China captured the main shock acceleration records. These records can be applied to site effect analyses, and then the site classification of those permanent stations can be carried out firstly, which will served as the fundamental information for further research. In this paper, the site of near-fault stations is classified by horizontal-to-vertical spectral ratio （HVSR） method according to the site class description of Japan earthquake resistant design code and response spectral shapes （RSS） method following the site class description of the 1997 Uniform Building Code （UBC） provisions. Then based on the detailed borehole data of those free-field stations, the equivalent shear wave velocity and overburden thickness are calculated and the site classifications are given by Chinese code for seismic design of buildings. Furthermore, for the stations having successful microtremor test data, the site dominant periods are computed to verify the results of site classification. Finally, combined with all the above results, the recommended site classes of near-fault permanent free-field stations are given.

Coordinatively unsaturated sites in zeolite matrix: Construction and catalysis

Zeolites with ordered porous structure of molecular size are widely employed as commercial adsorbents and catalysts.On the other hand,the zeolite matrix is regarded as an ideal scaffold for hosting coordinatively unsaturated sites.Remarkable achievements have been made dealing with the construction,characterization and catalytic applications of coordinatively unsaturated sites in zeolite matrix.Herein,a literature overview of recent progresses on this important topic is presented from the specific view of coordination chemistry.Different strategies to construction coordinatively unsaturated sites in zeolite matrix,in zeolite framework or extraframework positions,are first introduced and their characteristics are compared.Then,spectroscopic techniques to determine the existing states of cation sites and their transformations in zeolite matrix are discussed.In the last section,the catalytic applications of coordinatively unsaturated sites in zeolite matrix for various important chemical transformations are summarized.

A Single-Site Positioning Method Based on TOA and DOA Estimation Using Virtual Stations in NLOS Environment

This paper presents a single-site positioning method based on the joint estimation of propagation time-of-arrival(TOA) and direction-of-arrival(DOA), with the assist of virtual stations in the typical non-line-of-sight(NLOS) environment. Consider the influence of multipath noise on the positioning performance, the proposed method firstly presents a modified high-resolution estimation technique called Multipath noise Limiting Matrix Pencil(MLMP) algorithm to achieve the TOA/DOA estimations, in which the matrix pencil and matrix enhancement process are implemented to deal with the measurements from the uniform linear array(ULA) receiver. Meanwhile, the subspace dimension estimation is improved via an adaptive threshold, for enhancing the performance of high-resolution techniques in low signal-noise-ration(SNR) situation. Next the proposed method generates virtual stations utilizing the known floor plan of surrounding reflectors, and adopts a weighted Least Square(WLS) position estimator to calculate the required position, combining the TOA/DOA estimations with the location of virtual stations. Simulations are conducted to evaluate the proposed method under NLOSconditions, and the results show that comparing with the multipath fingerprinting scheme, the proposed method has better performance in various simulation scenarios.

Hazardous and Harmful Factors on Construction Sites and Their Prevention

In this paper, the status quo of safety production on construction sites and the hazardous and harmful factors in the construction process were analyzed, and corresponding suggestions were proposed to make up for the shortcomings of the safety production assurance system standards on construction sites.

Discussion on the Logistics Construction of Railway Container Freight Stations

From the perspective of logistics, the article discusses some essential functions and service functions of railway container freight stations. Then it plans the construction of the logistics operation system of container freight stations, and designs five main operating yards such as deconsolidation and groupage .yard, storage and distribution yard, container receiving-departure yard, container stack yard, and special cargo yard. The management pattern is discussed under the direction of modern business management theory. The ideas presented in this article is significant to the construction of railway container freight stations.

Framework for Improving Construction Health and Safety on Ghanaian Construction Sites

The enormity of the problem of construction accidents and hazards in the Ghanaian construction industry (GCI) calls for the need to engage in relevant research to equip stakeholders with the required knowledge to improve construction health and safety (CHS) and reduce site accidents and hazards. The complexity of the problem of accident causation explains a large number of conceptual models developed to aid the understanding of the dynamics involved in CHS. This paper involved a qualitative study to identify causes of accidents and hazards in the GCI and underlying issues requiring remedying and also a desk study to review Health and Safety related theories and concepts from extant literature to explain and contribute to the improvement of CHS. The paper contributes to the use of theories to advance studies on improving health and safety at construction sites, especially in developing countries like Ghana, where such studies have so far attracted little attention. The framework may enable construction stakeholders to easily identify problem areas on site and apply required improvement measures to create a healthier and safer construction site. The findings may provide useful knowledge to improve CHS and reduce site accidents and hazards, and also provide a multi-theory approach for understanding the dynamics of the complexity of the problems involved in CHS.

An Improved Ant Colony Optimization Algorithm for Construction Site Layout Problems

Meta-heuristic algorithms proved to find optimal solutions for combinatorial problems in many domains. Nevertheless, the efficiency of these algorithms highly depends on their parameter settings. In fact, finding appropriate settings of the algorithm’s parameters is considered to be a nontrivial task and is usually set manually to values that are known to give reasonable performance. In this paper, Ant Colony Optimization with Parametric Analysis (ACO-PA) is developed to overcome this drawback. The main feature of the ACO-PA is the ability of deciding the appropriate parameter values within the predefined parameter variations. Besides, a new approach which enables the pheromone information value to be proportional to the heuristic information value is introduced. The effectiveness of the proposed algorithm is investigated through the application of the algorithm to the construction site layout problems taken from the state-of-art. Results show that the ACO-PA can reduce transportation cost up to 16.8% compared to the site layouts generated by Genetic Algorithms and basic ACO. Moreover, the effects of parameter settings on the generated solutions are investigated.

Seismic Vulnerability of Building Construction Site

Building construction site plays an important role in the economic aspect of a region. So any disruption due to hazard event like earthquake can cause several direct and indirect damages. Direct damages can lead to the loss of equipments and qualified persons. Indirect damages can lead to inflation and loss of purchasing power. To deal with that situation, parameters that govern the vulnerability of building construction site have been identified. Using a MCDM （multiple criteria decision making） method, the priority order of these parameters has been set. Then a PVI （partial vulnerability index） and a GVI （global vulnerability index） are proposed. These indexes allow the classification of building construction sites according to their intrinsic vulnerability and seismic vulnerability respectively that is through the use of a given classification. Several Algerian building construction sites belonging to different seismic zones were considered in order to show the applicability of the method.

The Application of Principle of Automatic Control in the site Management of Electric Power Construction Enterprise

It is need to establish site project department during the construction of electric power project.The head office should design and build the main structure,continually improve structure of project department,meantime,positively apply principle of automatic control to improve the site management of electric power construction.In this article,the application strategy of principle of automatic control is analyzed focusing on the site work of electric power construction.

Discussion on the Relationship between Different Earthquake Magnitude Scales and the Effect of Seismic Station Sites on Magnitude Estimation

Based on the earthquake catalog reported by the Chinese digital seismic network in recent years,we select the earthquakes with both surface wave magnitude and local magnitude and fit them into a relationship between the two magnitudes.The systematic difference is found from the formula which has been used for 30 years.Because of a large dynamic range and wide frequency range of the current digital observation system,in addition to a larger number of stations and earthquakes being used compared to before,the relation obtained in this paper seems more reliable.Our calculation shows that there is no significant difference before and after magnitude conversion so we suggest the abandonment of magnitude conversion.The site response of a station consists of amplification at different frequencies.The amplification is equal to about 1 and changes little with frequency at stations located on basement rock,and it is greater than 1 at low frequency ranges and less than 1 at high frequency ranges at stations located on sediment layers.The difference between magnitudes from single station located on sediment layer and the average magnitude from the whole network increases from negative to positive with period.It seems that there is no fixed station correction factor and the station correction method does not work to improve the accuracy and magnitude estimates.

New-concept Design Innovation of Passenger Station Construction for Qinghe Railway Station of the Beijing-Zhangjiakou HSR

Qinghe Railway Station is the largest passenger station along the Beijing-Zhangjiakou HSR and will serve as the originating station of this line during the A 2022 Winter Olympics.It is also one of the eight major passenger stations in.Beijing.During the construction of this station,all units involved in the construction have made their effors to learn and understand the new concept of building up a“well-connected,filly-integrated,environment-friendly,passenger-oriented,economically-efficient,culturally-rich,inelligent and convenient”passenger station in the new era.Qinghe Railway Station of the Beijing-Zhangjiakou HSR was completed and opened to traffic by the end of 2019 through exploration of new-concept design innovation for passenger station construction in the new era,which was widely praised by the general public.The paper summarizes how the new design concept of passenger station construction is innovated and implemented during the construction of Qinghe Railway Station,thus providing a reference for the future construction of passenger stations.

Systematic Research and Innovation Practice on New Concepts of Construction for Xiong'an Railway Station

As the first major transport infirastructure in Xiong'an New Area,Beijing-Xiong an Intercity Railway is an important step for China State Railway Group Co.A Ltd.to quickly implement the major strategic plan of CPC Central Committee and the State Council.for the establishment of Xiong'an New Area.Xiong'an Station with double-floor spacious waiting areas and the wonderfiul integration of overpass and station building is the first modern integrated transport hub of this kind in China.Based on the characteristics of Xiong'an Station and in the light of the relevant new theories,methods and technologies,systematic studies and innovative practices on the new concept of building up a"well-connected,filly-integrated,environmen-frindly,passenger-oriented,economically-efficient,uurally-rich,intelligent and convenient"passenger station are carried oul,which achieve good results of application and help accumulate valuable experiences for the construction of passenger stations of Chinese high-speed railways in the new era.

Research on Practice of Excellent Railway Passenger Station Construction and High-quality Development

Taking the construction of excellent passenger stations in Beijing-Tianjin-AHebei region as the research object,the paper discusses the implementation of the new concept of building up“well-connected fully-integrated,envioment-friendlyy passenger-oriented,economically-eficient,culturally-rich intelligent and convenient”railway passenger stations It then strives to analyze the connotation of an excellent railway passenger station,the construction and management methods,and the innovation of the working mechanism in the new era.It offers thoughts and methods for promoting the highquality development in the practice of construction for innovative development of excellent passenger stations.

Development of a Fuzzy Fire Risk Evaluation Model for Building Construction Sites in Hong Kong

Earlier research works on fire risk evaluation indicated that an objective,reliable,comprehensive,and practical fire risk evaluation model is essential for mitigating fire occurrence in building construction sites.Nevertheless,real empirical studies in this research area are quite limited.This journal paper gives an account of the second stage of a research study aiming at developing a fuzzy fire risk evaluation model for building construction sites in Hong Kong.The empirical research findings showed that the overall fire risk level of building construction sites is 3.6427,which can be interpreted as“moderate risk”.Also,the survey respondents perceived that“Restrictions for On-Site Personnel”is the most vital fire risk factor;with“Storage of Flammable Liquids or Dangerous Goods”being the second;and“Attitude of Main Contractor”the third.The proposed fuzzy fire risk evaluation model for building construction sites can be used to assess the overall fire risk level for a building construction site,and to identify improvement areas needed.Although the fuzzy fire risk evaluation model was developed domestically in Hong Kong,the research could be reproduced in other nations to develop similar models for international comparisons.Such an extension would provide a deeper understanding of the fire risk management on building construction sites.