In order to strengthen and toughen the functional refractory, carbon fibres were introduced as reinforcement in aluminium-carbon refractories in a new way using direct dispersion of the binding agent. The effects of different carbon fiber contents on the properties of aluminum-carbon refractories were studied. The changes of bulk density, apparent porosity, flexural strength at room temperature, compressive strength, thermal shock resistance and high-temperature flexural strength of the samples after high temperature treatment were compared and analyzed. Changes in the physical phase and morphology of the samples at different heat treatment temperatures were analyzed. The results show that after heat treatment at 1 100 ℃, the flexural strength at room temperature, compressive strength, residual flexural strength and high temperature flexural strength of the samples with carbon fiber were effectively improved compared with those without carbon fiber. Among them, the performance is optimal when the carbon fiber content is 0.1%. Well-developed silicon carbide whiskers were obtained from the carbon fiber samples heat-treated at 1 500 ℃ and bridged carbon fibres with the matrix as observed by SEM. This suggests that suitable carbon fibre-doped can make the sample obtain excellent high-temperature service performance will Under the dual reinforcement of carbon fiber and silicon carbide whiskers.

Underground diaphragm wall has great advantages in the application of deep foundation pit support in the basement of high-rise buildings, subway stations and other projects. However, for the construction of underground diaphragm wall under the complex geological conditions of soft upper and hard lower strata and high groundwater level, as well as the complex environmental conditions such as high support rate into rock, near the construction and adjacent to the operation range of subway, there are some problems such as easy to collapse holes, low trough efficiency and high construction cost. Therefore, the construction technology of pile-diaphragm wall integration supporting the foundation pit was studied. By replacing this part of the deep ground connection wall embedded in the breezed rock layer with cast-in piles, the difficulty and workload of hard rock troughs are reduced, and the safety risks of adjacent buildings and subway operations are reduced.

In response to the increasingly growing logistics delivery demands in rural areas, optimizing the last-mile delivery model, reducing delivery costs, and improving service quality have become urgent issues. Based on a parallel delivery model using delivery vehicles and drones, and considering the characteristics of logistics distribution in rural areas, aims to maximize total delivery profit by constructing a parallel delivery model that incorporates the specific features of rural areas. An improved ant colony algorithm was employed to solve the model, and the feasibility of the algorithm was validated using Solomon benchmark instances. The research results demonstrate that the parallel delivery of vehicles and drones has significant advantages over the traditional single-mode delivery of vehicles or drones.

Considering the effect of the separation between the supporting layer and the base layer of the ballastless railway caused by foundation settlement, a simplified method was proposed for calculating the rail deformation of the ballastless railway to tunnelling underneath. Firstly, the track slab and the supporting layer were supposed as a composite elastic beam, and a simplified equation for the deformation of ballastless railway composite beams induced by shield tunneling was proposed by ignoring the influence of fasteners on the composite beam deformation. Afterwards, the composite beam was divided into a void zone and a joint zone, and the analytical solutions for the deformations of the composite beams caused by tunnlling underneath were proposed based on the elastic foundation beam theory. Furthmore, the rail was regarded as an Euler beam connecting with the composite beam by the dispersed spring, and the equations for the rail deformation caused by the composite beam deformation were derived. Based on the above, compared with the numerical simulation and theoretical results in the existing literature, the proposed simplified method of the ballastless railway caused by tunneling underneath was validated. Finally, the influences of model parameters on the rail deformation to tunnelling underneath were discussed, including the tunnelling induced ground loss rate, the composite beam bending stiffness, the fastener stiffness, and the rail bending stiffness. The results indicate that the theoretical calculation results were overestimated by neglecting the local suspension effect of the supporting layer. Reducing the tunnelling induced ground loss rate, strengthening the composite beams and rails can control the rail deformation of the ballastless railway caused by tunnlling undercrossing, but strengthening the fasteners stiffness may increase the unevenness of rail deformation.

Tunnel construction ventilation can effectively eliminate harmful gases and dust, and ensure the safety of construction environment. Taking an extra-long road tunnel as an example, the air demand for the construction of inclined shafts and tunnels was calculated with multiple working faces, choose the appropriate fan models, and the tunnel construction ventilation in stages was designed according to the construction progress of inclined shafts and main caves. A section of the split tunnel was used as a ventilation tunnel, and the roadway + pressurized ventilation method is adopted to shorten the length of the air supply ducts. FLUENT software was used to establish a three-dimensional numerical model of multi-working face construction ventilation, in-depth study of CO(carbon monoxide) diffusion regulations in tunnels. The results of the study show that CO migrates from near the tunnel face to the entrance in the form of “air mass”, and the migration rate is positively correlated with the ventilation wind speed in the tunnel.The location of the high CO concentration zone at the intersection of the inclined shaft gradually shifts to the right (low velocity zone) as the wind velocity ratio gradually becomes larger, and the maximum concentration gradually decreases.The wind speed ratio has no significant effect on the change of CO concentration in the left hole.

Starting from a low-carbon perspective, the relationship between the agglomeration of productive service industries, green technology innovation, and industrial green total factor productivity was explored through provincial research data from 2003 to 2021. The results show that the impact of specialized agglomeration of productive service industries on industrial green total factor productivity exhibits a “U” - shaped characteristic, while the impact of diversified agglomeration exhibits an “N” - shaped characteristic. The specialized agglomeration of productive service industries has a significant positive impact on industrial green total factor productivity through the mediating effect of green technology innovation, while there is no mediating effect in diversified agglomeration.There are differences in the impact results among the three major regions of East, Central, and West. The specialized agglomeration of productive service industries in the eastern region is more flexible, while the diversified agglomeration of productive service industries in the central region is more significant. It is found that a good agglomeration of productive service industries can accelerate the improvement of industrial green total factor productivity. Based on emphasizing development characteristics and growth models, targeted green technology innovation and precise policies can be implemented to construct a localized policy model for productive service industries with Chinese characteristics, providing policy references and theoretical guidance for promoting industrial green development.

RCEP (Regional Comprehensive Economic Partnership) provides broad space and opportunities for the optimization and upgrading of industrial structure in Guangxi, and promotes high-quality economic development in Guangxi. By conducting in-depth research on the opportunities and challenges brought by RCEP,reference for Guangxi is proposed to formulate a scientific and reasonable path for optimizing and upgrading its industrial structure. By using comparative analysis, the problems and challenges facing Guangxi’s current industrial structure were analyzed. A path for optimizing and upgrading Guangxi’s industrial structure under RCEP is proposed. Guangxi should fully utilize the policy dividends of RCEP to promote technological innovation, accelerate the development of digital technology, extend the industrial chain, highlight green development, transform traditional industries, optimize industrial structure, and optimize regional layout. raditional industries, optimize industrial structure, and optimize regional layout.

Digital inclusive finance is an important way to promote high-quality economic development and achieve consumption expansion and upgrading. It is found that digital inclusive finance can significantly improve the consumption level of households in China and the western region by using CHFS (China Household Finance Survey) micro household data, and digital inclusive finance can help household consumption through the intermediary mechanism of improving household income and regional digitalization. In order to make digital inclusive finance better realize the expansion and upgrading of consumption, on the one hand, it is necessary to increase policy support and promote the construction of digital infrastructure; On the other hand, it is necessary to improve the consumption and financial consumption concepts of households.

China’s provincial panel data from 2011 to 2021 were used, the entropy weight TOPSIS(technique for order preference by similarity to ideal solution) method was used to measure the level of agricultural low-carbon development, and financial support for agriculture as financial support for agriculture was expressed to illustrate the impact of financial support for agriculture on agricultural low-carbon development. The intermediary effect of rural human capital in the relationship between the two was discussed. It is found that fiscal support for agriculture has a positive promoting effect on low-carbon agricultural development, and rural human capital plays a mediating role in it. Heterogeneity results indicate that the impact of fiscal support for agriculture in northern regions is greater than that in southern regions.

In order to further explore the feasibility of key technologies, related products, markets, and policy measures in the hydrogen energy industry at different time nodes, an analysis framework for the development of the hydrogen energy industry was constructed based on industrial technology road-map. The incoPat patent database was used to clarify the current development status of the hydrogen energy industry through technology patent retrieval and analysis. Adopting questionnaire survey and expert interview afterwards,the development trend of China’s hydrogen energy industry is predicted and depicted from aspects of industrial environment, main products, key technologies, etc. Based on above predictions and depictions,a roadmap for the development of China’s hydrogen energy industry is drawn. In combination with the construction practice of Changping “Energy Valley”, suggestions for industrial development are systematically put forward, such as increasing technological research and development in the field of hydrogen production using renewable energy, actively promoting pilot demonstrations, accelerating the construction of a national hydrogen energy supply system and a whole industry chain system of hydrogen industry with green hydrogen as the core, improving the standard system, and strengthening international cooperation.