Subsurface multi-physical characterization of mountain excavation and city construction in loess plateau with a fiber-optic sensing system

Mountain excavation and city construction(MECC)projects being launched in the Loess Plateau in China involve the creation of large-scale artificial land.Understanding the subsurface evolution characteristics of the artificial land is essential,yet challenging.Here,we use an improved fiber-optic monitoring system for its subsurface multi-physical characterization.The system enables us to gather spatiotemporal distribution of various parameters,including strata deformation,temperature,and moisture.Yan’an New District was selected as a case study to conduct refined in-situ monitoring through a 77 m-deep borehole and a 30 m-long trench.Findings reveal that the ground settlement involves both the deformation of the filling loess and the underlying intact loess.Notably,the filling loess exhibits a stronger creep capability compared to underlying intact loess.The deformation along the profile is unevenly distributed,with a positive correlation with soil moisture.Water accumulation has been observed at the interface between the filling loess and the underlying intact loess,leading to a significant deformation.Moreover,the temperature and moisture in the filling loess have reached a new equilibrium state,with their depths influenced by atmospheric conditions measuring at 31 m and 26 m,respectively.The refined investigation allows us to identify critical layers that matter the sustainable development of newly created urban areas,and provide improved insights into the evolution mechanisms of land creation.

A climatic environmental performance assessment method for ecological city construction:Application to Beijing Yanqi Lake

In contrast to the input perspective for evaluating planning metrics, this research takes the climatic environmental output effects as the starting point for assessing ecological city construction. Based on approaches such as observation data analysis, meteorological model simulation, and remote sensing, a set of climatic environmental performance assessment methods is developed and established. These methods mainly focus on surface ventilation assessment and urban thermal environment assessment. With the Yanqi Lake ecological development demonstration area located in Huairou district, Beijing as an example, the assessment of the local climatic environment before and after the construction are conducted, and relevant policy suggestions for urban planning and construction are presented. The results show that after development, the ventilation capacity will decrease overall and the ventilation potential index will decrease from 0.53 to 0.44. While this is not a large reduction, and is still at a favorable level, the ventilation potential in some local areas will markedly decrease. Furthermore, the thermal environment will become poorer to some extent; the urban heat island(UHI) area and intensity will increase compared with the current situation;continuous heat islands may occur in local areas; the UHI potential index of the core area will rise from 0.0878 to 0.1217(still a favorable level).Therefore, urban surfaces should be carefully developed and arranged during planning. It is suggested that the negative impacts of large areas of urban construction on the local climatic environment in the Yanqi Lake could be mitigated by 1) strengthening the airflow by introducing fresh,cold, northwesterly air via constructed ventilation corridors, 2) increasing the number of ecological cold sources, particularly for water bodies and green belts to prevent the UHI in the southern region of Yanqi Lake from becoming linked with each other, and 3) considering a pre-program before sub-domain and building planning to obtain optimum building locations. Different construction standards should be developed for different ventilation potential and UHI intensity levels. For strong heat island areas, land areas should be reserved to serve as cold sources.

Countermeasures for Solving the Environmental Problems and Accelerating the Model City Construction of Xi'an

Through careful study, it found that the key and difficult points of affecting and restricting Xi＇an to reach the model city construction standards in provincial and national levels were ＂urban air environment quality standards＂ and ＂water qualification rate of urban water environment function area＂. In order to tackle with the weak links, highlight the important points and focus on the difficult points to strengthen scientific and technological innovation, we actively explored new ideas and ways to resolve the dilemma in meeting the two standards of model city construction, and we managed to put forward the countermeasures to resolve the dilemma through innovating system and mechanism. ＂Place master system＂ should be carded out quickly to meet the ＂urban air environment quality standards＂, while ＂river master system＂ should be implemented as soon as possible to reach the ＂water qualification rate of urban water environment function area＂. The aim of this study was to enhance the qualification rates of the indicators for model city construction to make Xi＇an successfully pass the provincial and national assessment of model city construction through dealing with the weak links to accelerate the realization of becoming model environmental protection city.

China＇s Sponge City construction： A discussion on technical approaches

Since 2014, China has been implementing the Sponge City Construction initiative, which represents an enormous and unprecedented effort by any government in the world for achieving urban sustainability. According to preliminary estimates, the total investment on the Sponge City Plan is roughly 100 to 150 million Yuan （RMB） （$15 to $22.5 million） average per square kilometer or 10 Trillion Yuan （RMB） （$1.5 Trillion） for the 657 cities nationwide. The Sponge City Plan （SCP） calls for the use of natural processes such as soil and vegetation as part of the urban runoff control strategy, which is similar to that of low impact development （LID） and green infrastructure （G1） practices being promoted in many parts of the world. The SCP includes as its goals not only effective urban flood control, but also rainwater harvest, water quality improvement and ecological restoration. So far, the SCP implementation has encountered-some barriers and challenges due to many factors. The present paper presents a review of those barriers and challenges, oftizrs discussions and recommendations on several technical aspects such as control goals and objectives; planning/design and construction of LID/GI practices; performance evaluation. Several key recommendations are proposed on Sponge City implementation strategy, Site-specific regulatory fi＇amework and technical gmdance, Product innovation and certification, LID/GI Project financing, LID/G1 profcssional training and certification, public outreach and education. It is expected that the successful implemen!atiun of the. SCP not only will bring about a sustainable, eco-friendly urbanization process in China, but also contribute enormously to the LID/Gl research and development with the vast amount of relevant data and experiences generated from the Sponge City construction projects.

Urban Big Data and the Development of City Intelligence

This study provides a definition for urban big data while exploring its features and applications of Chi- na＇s city intelligence. The differences between city intelligence in China and the ＂smart city＂ concept in other countries are compared to highlight and contrast the unique definition and model for China＇s city intelligence in this paper. Furthermore, this paper examines the role of urban big data in city intel- ligence by showing that it not only serves as the cornerstone of this trend as it also plays a core role in the diffusion of city intelligence technology and serves as an inexhaustible resource for the sustained development of city intelligence. This study also points out the challenges of shaping and developing of China＇s urban big data. Considering the supporting and core role that urban big data plays in city intel- ligence, the study then expounds on the key points of urban big data, including infrastructure support, urban governance, public services, and economic and industrial development. Finally, this study points out that the utility of city intelligence as an ideal policy tool for advancing the goals of China＇s urban de- velopment. In conclusion, it is imperative that China make full use of its unique advantages-including using the nation＇s current state of development and resources, geographical advantages, and good hu- man relations-in subjective and objective conditions to promote the development of city intelligence through the proper application of urban big data.

The Scale of Constructing Mountainous Cities in Yunnan Province based on “Benchmark” Farmlands

In 2011, Yunnan provincial committee and government proposed the strat- egy of constructing mountainous cities in order to protect farmlands and guarantee crop safety, which makes full use of hills and gentle-slopes and transforms land use pattern. However, social and economic development performs unevenly in Yun- nan, supplemented by varied geographical conditions, so that constructing mountain- ous cities should proceed as per local conditions. The research proposed the con- trol of constructing mountainous cities provided crop safety under the principle of farmland protection and measured the quantities of demanded construction lands ac- cording to science of population prediction and ekistics, based on which the control scales of constructing mountainous cities were determined by multiplying basic farm- land coefficient and the area of newly increased construction lands. The research is of significance for guiding the construction of mountainous cities and avoiding the occupation of construction lands on farmlands.

The Issue of Street Construction in the Transformation of Old City Areas in Medium-and-Small-Sized Cities

Excerpts: The rapid economic development of cities provides the material basis for the transformation of the oldcities. The reconstruction of streets is the first issue being looked at. In the past few years,experiences have beengained and problems encountered. For instance, only some sections of the streets are reconstructed, the scale and de-velopment program of reconstruction are decided without any comprehensive, conceptual planning program, Thispaper attempts to analyse the reasons and defects of the past practice and some suggestions are made on improve-ment measures. It is pointed out in particular, that the transformation of streets should be based in the need, devel-opment potential, characteristics and specific role of the cities in order to enable the streets to be reconstructed incoordination with the transformation of the cities as a whole.

Research on Spatio-Temporal Differentiation Characteristics of the Construction Level of Green and Plaza Land in China

Green and plaza land(GPL)is one of the basic elements of urban construction,and is also the most basic public space to meet the needs of citizens for a better life.The exploration on its internal development laws can provide theoretical foundations for the planning of GPL and creating good human settlements.Taking 612 cities in China as the study area and from the"people-land"perspective,this paper selects the total GPL area,the per capita GPL area,and the land use proportion of per capita GPL as indicators to analyze the spatio-temporal differentiation characteristics and evolution rules of the construction level of GPL in China from 1996 to 2016,by using mathematical statistics and spatial analysis methods.The result shows:(1)from a national perspective,the construction level of GPL in China has been rapidly improved along with the temporal evolution,but there is still a big gap from the upper limit of the standard.In terms of the spatial distribution,regional differences have always been great,and the cities scoring below the standard are concentrated in the eastern and central regions,while high-scoring cities are more concentrated in the western region;the distribution of the land use proportion of per capita GPL is in a pattern that the eastern region has the highest proportion,followed by the western region,central region,and northeastern region successively.(2)From the perspective of scale,differences between cities of different sizes exist over a long period of time,and there is an obvious imbalance in the per capita GPL area as well as the land use proportion of per capita GPL between different cities.The construction level shows that small cities have the highest level,followed by medium-sized cities and then large cities.

MLR: Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11 Cities Approved

On Jan.25,2018,the Ministry of Land and Resources(MLR)declared that the Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11Cities including Shenyang,Nanjing,Hangzhou,etc.,has been approved.MLR emphasized that the pilot areas should follow the principle of house for living,not for speculation.And according

A Review of Housing Construction in China's Cities

In this article,the author briefly reviews the urban housing construction in the 40 yearssince the founding of New China,especially over the recent ten years.He puts emphasis on theanalysis of the benefits and defects brought about by the financing and banking system for urbanhousing construction before and during the reform of housing system.