Effect of burial depth of a new tunnel on the seismic response of an existing tunnel

Burial depth is a crucial factor affecting the forces and deformation of tunnels during earthquakes.One key issue is a lack of understanding of the effect of a change in the buried depth of a single-side tunnel on the seismic response of a double-tunnel system.In this study,shaking table tests were designed and performed based on a tunnel under construction in Dalian,China.Numerical models were established using the equivalent linear method combined with ABAQUS finite element software to analyze the seismic response of the interacting system.The results showed that the amplification coefficient of the soil acceleration did not change evidently with the burial depth of the new tunnel but decreased as the seismic amplitude increased.In addition,the existing tunnel acceleration,earth pressure,and internal force were hardly affected by the change in the burial depth;for the new tunnel,the acceleration and internal force decreased as the burial depth increased,while the earth pressure increased.This shows that the earth pressure distribution in a double-tunnel system is relatively complex and mainly concentrated on the arch spandrel and arch springing of the relative area.Overall,when the horizontal clearance between the center of the two tunnels was more than twice the sum of the radius of the outer edges of the two tunnels,the change in the burial depth of the new tunnel had little effect on the existing one,and the tunnel structure was deemed safe.These results provide a preliminary understanding and reference for the seismic performance of a double-tunnel system.

Research on the Development of Smart Animal Husbandry in Beijing

With the rapid development of agricultural science and technology,animal husbandry,as an important pillar in the field of agriculture,is gradually moving towards a new era of smart animal husbandry with the deep integration of informatization and digitalization.This transformation not only breaks through the traditional production mode of animal husbandry,but also promotes it to a new form under the Internet ecology,draws a new blueprint for the development of agriculture and animal husbandry,and gives birth to numerous potential business opportunities for the development of new agriculture.However,the practice and promotion of smart animal husbandry is not a smooth road,and many challenges and problems need to be solved urgently.On the basis of an in-depth investigation of the development status of smart animal husbandry in Beijing,this paper comprehensively analyzes the current problems,including the difficulty of technology integration,the lack of talent reserve,and the need to improve the policy environment.In view of these problems,it puts forward a series of practical suggestions,in order to speed up the development of animal husbandry in Beijing to the direction of smart development,and realize the sustainable development of animal husbandry.

Durability evaluation for existing railway engineering: a review

Purpose – This study aims to analyze the factors, evaluation techniques of the durability of existing railwayengineering.Design/methodology/approach – China has built a railway network of over 150,000 km. Ensuring thesafety of the existing railway engineering is of great significance for maintaining normal railway operationorder. However, railway engineering is a strip structure that crosses multiple complex environments. Andrailway engineering will withstand high-frequency impact loads from trains. The above factors have led todifferences in the deterioration characteristics and maintenance strategies of railway engineering compared toconventional concrete structures. Therefore, it is very important to analyze the key factors that affect thedurability of railway structures and propose technologies for durability evaluation.Findings – The factors that affect the durability and reliability of railway engineering are mainly divided intothree categories: material factors, environmental factors and load factors. Among them, material factors alsoinclude influencing factors, such as raw materials, mix proportions and so on. Environmental factors varydepending on the service environment of railway engineering, and the durability and deterioration of concretehave different failure mechanisms. Load factors include static load and train dynamic load. The on-site rapiddetection methods for five common diseases in railway engineering are also proposed in this paper. Thesemethods can quickly evaluate the durability of existing railway engineering concrete.Originality/value – The research can provide some new evaluation techniques and methods for thedurability of existing railway engineering.

Efficiency evaluation and optimizing implementation strategy of green renovation market in existing residential areas in China

The key to the healthy development of the market for green renovation of existing settlements lies in effectively playing the role of market resource allocation,and scientific evaluation of the current market operation efficiency is a prerequisite for the optimization and adjustment of market operation.Based on the perspective of market operation effectiveness,we start from the connotation and significance of the evaluation of the operation efficiency of the market of green renovation of existing settlements,construct the evaluation index system of the operation efficiency of the market of green renovation of existing settlements,use the hierarchical analysis method(AHP)and fuzzy comprehensive evaluation method(Fuzzy),establish the fuzzy comprehensive evaluation model,and finally,based on the operation process reengineering,financing model innovation,service platform expansion and market environment improvement,it structures the operation improvement path of the green renovation market of existing settlements and promotes the orderly operation of the green renovation market of existing settlements.

Development Status and Countermeasures of Farmers' Professional Cooperatives in Shangqiu City

Farmers' professional cooperatives develop in various forms,and with the continuous improvement of development level,social effects have gradually appear.Based on the specific situation of farmers' professional cooperatives in Shangqiu City,this paper expounded the development status of farmers' professional cooperatives in Shangqiu City,analyzed and discussed various problems encountered in the development process of farmers' professional cooperatives,and put forward some countermeasures and suggestions,such as establishing and perfecting cooperative rules and regulations,financing from multiple channels,introducing technical talents in various ways,breaking the information asymmetry restriction by various means,and giving full play to government functions,aiming to further promote standardized,large-scale,healthy and sustainable development of farmers' professional cooperatives.

Operation optimization strategy of existing residential building energy-saving renovation market:From the perspective of subject behavior

The energy-saving renovation of existing residential buildings is a crucial measure to achieve the strategic goal of energy conservation and emission reduction in China and build ecologically livable cities.This article focuses on the perspective of subject behavior,starting from analyzing the current situation and difficulties of the operation of the energy-saving renovation market for existing residential buildings in China,drawing on the practical experience of the operation of the existing residential building energy-saving renovation market abroad.Based on principles such as systematicity,humanization,feasibility,and sustainability,the article constructs an operation optimization system of the existing residential building energy-saving renovation market from the perspective of subject behavior.In order to provide a reference for the healthy and orderly operation of the existing residential building energy-saving renovation market,this paper proposes implementation strategies for optimizing the operation of the existing residential building energy-saving renovation market.Suggestions are proposed from four aspects:optimizing the market environment,innovating the financing model,building the information sharing platform,and utilizing the synergies of the main subjects.

Nonlinear Pushover Analysis of the Influences on RC Footing for the External Elevator Well

In contemporary society, reducing carbon dioxide emissions and achieving sustainable development are paramount goals. One effective approach is to preserve existing RC (Reinforced Concrete) buildings rather than demolishing them for new construction. However, a significant challenge arises from the lack of elevator designs in many of these existing RC buildings. Adding an external elevator becomes crucial to solving accessibility issues, enhancing property value, and satisfying modern residential buildings using convenient requirements. However, the structural performance of external elevator wells remains understudied. This research is designed by the actual external elevator project into existing RC buildings in Jinzhong Rd, Shanghai City. Specifically, this research examines five different external elevator wells under nonlinear pushover analysis, each varying in the height of the RC (Reinforced Concrete) footing. By analyzing plastic hinge states, performance points, capacity curves, spectrum curves, layer displacement, and drift ratio, this research aims to provide a comprehensive understanding of how these structures of the external elevator well respond to seismic events. The findings are expected to serve as a valuable reference for future external elevator projects, ensuring the external elevator designs meet the seismic requirements. By emphasizing seismic resistance in the design phase, the research aims to enhance the overall safety and longevity of external elevator systems integrated into existing RC buildings.

A discussion on producing agro-residue composites with isocyanate resins

With the urgent shortage of forest resource in China, using agro-residues as raw materials of composite become increasingly important. Agro-residue is the most potential fiber resource, which is helpful to sustainable development of composite industries in China. Based on a great deal of researches, this paper summarized and discussed some problems in using agro-residues as raw materials of composites, including raw material preparation, hot-pressing, bonding technology, preventing composite from going moldy. It is proposed that to manufacture the composite of rice straws or wheat straws, the isocayante resin is a suitable adhesive, and the appropriate technologies, bonding, and treatment measures are also needed.

Raman Studies on Species in Single and Mixed Solutions of Molybdate and Vanadate

Raman spectroscopy was applied to investigate the speciation in both single and mixed solutions of molybdate and vanadate at pH values from 10.0 to 1.0. Evidence was obtained for the difference of existing forms between these two elements. Vanadium mainly exists as （VO3）n^n- while Mo is MoO4^2- in the pH range of 9.0-7.5. This difference is the theoretical basis for many available separation process. The species in the binary system was identified by comparing the Raman spectra with that in the single systems. Molybvanadates are formed below pH=6.5, which may partly be ascribed to the replacement of V atoms by Mo atoms in some V-O-V groups. Vanadium mainly exists as the decavanadate species in the pH range of 6.0-2.0. The predominant species of Mo are heteropolyanions having structural features of heptamolybdate rather than MosO26^4- and Mo36O112^8- which are the predominant Mo species in single solution at pH=2.0-1.0.

Problems and Strategies for Arable Land Eco-conservation in China

Arable lands are so important to China concerning food security and ec- onomy development. And eco-problems are rising and food security risks are widespread. The research reviewed quantity and quality of domestic arable lands, analyzed existing problems and proposed countermeasures for reinforcing domestic arable land conservation.

On the Experience, Problems in Science and Technology Services of Basic Scientific Research Institutes and Suggestions——Taking Zhenjiang Institute of Agricultural Sciences in Hilly Areas of Jiangsu as an Example

Taking the Jiangsu Province as Zhenjiang Academy of Agricultural Sciences in Hilly Areas of an example, the paper elaborated the advanced practices of agricultural research institutes in agricultural science and technology services and analyzed the difficulties and solutions in the services. process of science and technologyservices.

FNM method for estimating reliability of existing bridges

Combined with current specifications and stress characteristics of concrete filled steel tubular （CFST） arch bridges, the determination principle of safe-middle-failure threestage mode is given. Accordingly, damage probability and failure probability and the corresponding reliability indices are calculated; a direct relationship between reliability indices and three-stage working status is made. Based on the three-stage working mode, a combined FNM （finite element-neural network- Monte-Carlo simulation） method is put forward to estimate the reliability of existing bridges. According to time-dependent reliability theory, subsequent service time is divided into several stages; minimum samples required by the Monte-Carlo method are generated by random sampling; training samples are calculated by the finite element method, and the training samples are extended by the neural network; failure probability and damage probability are calculated by the Monte-Carlo method. Thus, time dependent reliability indices are obtained, and the working status is judged. A case study is investigated to estimate the reliability of an actual bridge by the FNM method. The bridge is a CFST arch bridge with an 83.6 m span and it has been in operation for 10 years. According to analysis results, in the tenth year, the example bridge is still in safe status. This conclusion is consistent with the facts, which proves the feasibility of the FNM method for estimating the reliability of existing bridges.

Thoughts on Building Nanchang a Forestry City

From the concept of urban forest and status quo of urban forest in Nanchang,the problems existing on urban forest were proposed,as well as countermeasures and suggestions.

A Research on Oral English Competence of English Majors in XFU

Nowadays, it is obvious to see the importance of oral English competence. Cultivating students' oral English competence is not only the need of the development of the society but also the development of college students. This paper will analyze existing problems of English majors in Xi'an Fanyi University. Based on this, the author will put forward some countermeasures to improve their oral English competence.

Existing State and Partitioning of Rare Earth on Weathered Ores

The existing state and partitioning of rare earth （RE） on weathered ores in Longnan County（LN）, Xingfeng County（XF） and Ninghua County（NH） were characterized systematically by standard geological analytical methods. It is found that RE in the weathered rare earth ores exist as four phases： （a） water soluble, （b） ion-exchangeable, （c） colloidal sediment （oxides）, （d） minerals, in which mainly as ion exchangeable phase, accounting for nearly 80% of total RE, with about 20% in the form of colloid sediment phase and mineral phase, but very little as aqueous soluble phase. These rare earth partitioning were mainly chosen mid-heavy RE elements, occupying above 60%, but not equal in the four phases. The mid-heavy RE elements were primarily enriched in the ion exchangeable phase up to 40%, while the containment of cerium dioxide is below 2 %. The cerium deficiency occurs in the ion exchangeable phase in weathered ore. It results from that the Ce^3＋ is oxidized into Ce^4＋ and changes into CeO2. For LN ore, the containment of Y is high in weathered ore because Y-minerals are abundant in original rock.

A Review of Recent Advances in Research on Asian Monsoon in China

This paper reviews briefly advances in recent research on monsoon by Chinese scholars, including primarily： （1） the establishment of various monsoon indices. In particular, the standardized dynamic seasonal variability index of the monsoon can delimit the geographical distribution of global monsoon systems and determine quantitatively the date of abrupt change in circulation. （2） The provision of three driving forces for the generation of monsoon. （3） The revelation of the heating-pump action of the Tibetan Plateau, which strengthens southerlies in the southern and southeastern periphery of the Plateau and results in a strong rainfall center from the northern Bay of Bengal （BOB） to the Plateau itself. （4） Clarification of the initial onset of the Asian Summer Monsoon （ASM） in the BOB east of 90°E, Indochina Peninsula （ICP） and the South China Sea, of which the rapid northward progression of tropical convection in the Sumatra and the rapid westward movement of the South Asia High to the Indochina Peninsula are the earliest signs. （5） The provision of an integrated mechanism for the onset of the East Asian Summer Monsoon （EASM）, which emphasizes the integrated impact of sensible heat over Indian Peninsula, the warm advection of the Tibetan Plateau and the sensible heat and latent heat over the Indochina Peninsula on the one hand, and the seasonal phase-lock effect of the northward propagation of low frequency oscillation on the other. （6） The revelation of the ＂planetary-scale moisture transport large-value band＂ from the Southern Hemisphere through to the Asian monsoon region and into the North Pacific, which is converged by several large-scale moisture transport belts in the Asian-Australian monsoon regions and whose variation influences directly the temporal and spatial distribution of summer rainfall in China. （7） Presenting the features of the seasonal advance of the EASM, the propagation of intraseasonal oscillation, and their relationship with rainfall in China; indicating that the intraseasonal oscillation of the EASM propagates in the form of a wave-train along the coast and behaves as monsoon surge propagating northward. （8） Describing the interannual and interdecadal variation of Asian monsoon, revealing the factors affecting it, and possible mechanisms of the variation of Asian monsoon. An elementary outlook on the existing problems and future direction of monsoon research is also provided.

Existing forms of REE in gold-bearing pyrite of the Jinshan gold deposit,Jiangxi Province,China

Rare earth element(REE) is widely used in various fields of geology.Study of the existing forms of REE in geological objects is a necessity for us to solve geological problems related with REE.This paper tried to make it clear the existing forms of REE in gold-bearing pyrite in Jinshan gold deposit by stepwise dissolution test with ICP-MS analysis.Results showed that content of REE in fluid-inclusions of gold-bearing pyrite was very low,which only took about 0.07%–0.70% of the ΣREE,and that of pyrite phase ...

Resilience-based retrofitting of existing urban RC-frame buildings using seismic isolation

The improvement of the seismic resilience of existing reinforced-concrete(RC) frame buildings, which is essential for the seismic resilience of a city, has become a critical issue. Although seismic isolation is an effective method for improving the resilient performance of such buildings, target-oriented quantitative improvements of the resilient performance of these buildings have been reported rarely. To address this gap, the seismic resilience of two existing RC frame buildings located in a high seismic intensity region of China were assessed based on the Chinese Standard for Seismic Resilience Assessment of Buildings. The critical engineering demand parameters(EDPs) affecting the seismic resilience of such buildings were identified. Subsequently, the seismic resilience of buildings retrofitted with different isolation schemes(i.e., yield ratios) were evaluated and compared, with emphasis on the relationships among yield ratios, EDPs, and levels of seismic resilience. Accordingly, to achieve the highest level of seismic resilience with respect to the Chinese standard, a yield ratio of 3% was recommended and successfully applied to the target-oriented design for the seismic-resilience improvement of an existing RC frame building. The research outcome can provide an important reference for the resilience-based retrofitting of existing RC frame buildings using seismic isolation in urban cities.

Deterioration mechanism and rapid detection of performances of an existing subgrade in southern China

To relieve the increasing traffic load, many early built highways need to be widened or reconstructed. The rapid performance detection to existing subgrades is important to their reasonable evaluation and maximized utilization. Based on five kinds of soils taken from an existing highway in southern China, three commonly detecting methods were used to determine their moisture contents, compaction degrees and resilient moduli. The results showed that the measured moisture contents were greater than the design value, and the compaction degrees decreased sharply compared to the original ones. The moisture and heat exchange produced a decrease in the resilient modulus of plate loading test(PLT) from the standard 60 MPa down to 40 MPa. Afterwards, the portable falling weight deflectometer(PFWD) and dynamic cone penetrometer(DCP) were used to evaluate the subgrade performances. The measured PFWD moduli and the DCP penetration rates were correlated with the resilient moduli of PLT, deflections of the Beckman beam test, compaction degrees and moisture contents. The correlation analysis indicates that both of two methods are suitable in rapid detecting subgrade performances, but PFWD method is more recommended for it has higher accuracy and efficiency.

Analysis of spudcan-footprint interaction in a single soil with nonlinear FEM

The footprints that remain on the seabed after offshore jack-up platforms completed operations and moved out provide a significant risk for any futurej ack-up installation at that site. Detrimental horizontal and/or rotational loads will be induced on the base cone of the jack-up platform leg （spudcan） in the preloading process where only vertical loads are normally expected. However, there are no specific guidelines on design of spudcan re-installation very close to or partially overlapping existing footprints. This paper presents a rational design approach for assessing spudcan-footprint interaction and the failure process of foundation in a single layer based on nonlinear finite element method. The rela- tionship between the distance between the spudcan and the footprint and the horizontal sliding force has been obtained. Comparisons of simulation and experimental results show that the model in this paper can deal well with the combined problems of sliding friction contact, fluid-solid coupling, and convergence difficulty. The analytical results may be useful to jack-up installation workovers close to existing footprints.