The increasing problem of urban traffic congestion has led to the extensive use of underground tunnels. However, tunnel lining cracks pose a major threat to the integrity and safety of the structure. Although the traditional repair method is effective, it often requires higher construction technology and higher cost, and may cause damage to the concrete structure. In this study, microbial-induced calcium carbonate precipitation (MICP) was combined with basalt fiber cloth to repair and reinforce tunnel lining cracks. Bacillus pasteurii was used to optimize the microbial mineralization process, and the effectiveness of the method on cracks with different widths was evaluated using a water seepage test. In addition, the mechanical properties of the reinforced tunnel lining were tested. The microbial mineralization process effectively repaired cracks with widths of 1 mm, 2 mm, and 3 mm. The use of unidirectional basalt fiber cloth increased the bearing capacity of the strengthened member by 12.5%. The combined reinforcement method also enhances the deflection performance and alleviates the influence of water seepage on the bonding performance. This innovative and sustainable approach not only provides an effective solution for the repair of tunnel lining cracks, but also contributes to the broader field of eco-friendly building materials. This study highlights the potential of using this combination approach to improve the durability and performance of underground infrastructure.

Pile–raft foundations are widely used in soft soil engineering due to their good integrity and high stiffness. However, traditional design methods independently design pile–raft foundations and superstructures, ignoring their interaction. This leads to significant deviations from actual conditions when the superstructure height increases, resulting in excessive costs and adverse effects on building stability. This study experimentally investigates the interaction characteristics of pile–raft foundations and superstructures in soft soil under different working conditions using a 1:10 geometric similarity model. The superstructure is a cast-in-place frame structure (beams, columns, and slabs) with bamboo skeletons with the same cross-sectional area as the piles and rafts, cast with concrete. The piles in the foundation use rectangular bamboo strips (side length ~0.2 cm) instead of steel bars, with M1.5 mortar replacing C30 concrete. The raft is also made of similar materials. The results show that the soil settlement significantly increases under the combined action of the pile–raft and superstructure with increasing load. The superstructure stiffness constrains foundation deformation, enhances bearing capacity, and controls differential settlement. The pile top reaction force exhibits a logarithmic relationship with the number of floors, coordinating the pile bearing performance. Designers should consider the superstructure’s constraint of the foundation deformation and strengthen the flexural capacity of inner pile tops and bottom columns for safety and economy.

Many ethnic minority autonomous regions in China, mainly in mountainous areas, have caused great harm to people’s life and property safety due to frequent geological disasters. Therefore, it has become an urgent task for the government to create a system for predicting, preventing and effectively responding to disasters, and to strengthen the ability of relevant regions to jointly resist disasters. This paper takes Mabian Yi Autonomous County as the research object, and studies the disaster management of Mabian Yi Autonomous County. The research focuses on geological disaster vulnerability evaluation, geological disaster hazard evaluation, geological disaster risk evaluation, and geological disaster carrying capacity evaluation. The two elements of geological disaster risk evaluation are vulnerability evaluation and hazard evaluation. The main element of geological disaster carrying capacity evaluation is risk evaluation. Through evaluation, it is found that the central and eastern regions of Mabian Yi Autonomous County can be used as population concentration areas and develop modern agriculture and tourism. The western and northeastern regions can be used as nature reserves. Based on the above evaluation results, the disaster management opinions of Mabian Yi Autonomous County are given. This makes the government have a certain reference basis in the preparation of regional construction policy planning. From the perspective of unique disaster management, this paper provides the government with a political governance model for ethnic minority areas through the harmonious development of man and nature, to achieve a goal of sustainable development.

In this study, aiming at the practical application of additional layer excavation technology in the renewal and reconstruction of old urban communities, the influence of different excavation methods on the settlement behavior of existing structures is deeply analyzed through numerical simulation experiments. It is found that the frame columns show basin-type settlement in the block layered excavation, basin excavation and central island excavation. The cumulative settlement of the middle column is the largest, and the corner column is the smallest. The settlement phenomenon is mainly concentrated around the frame columns Z6, Z7, Z10 and Z11, and the change law of the cumulative settlement value conforms to the linear function distribution. By defining the cumulative settlement rate (a) as an index to measure the influence degree of the existing structure, it is found that the a value of the middle column is the largest, the side column is the second and the corner column is the smallest, and the a value of block layered excavation is the largest, and the central island excavation is the smallest. Considering the construction period, block layered excavation may be a more appropriate choice. The comparative analysis of the research results and the model experiment results confirms the feasibility of the improved model experiment, provides an important theoretical basis and practical guidance for the renewal and transformation of old urban communities and is of great significance for improving the utilization efficiency and safety of existing buildings.

China is strengthening the construction of the disaster resistance capacity of its mountain buildings, which increases the demand for RC Diaojiaolou reinforcement technology. In this paper, the performance of RC Diaojiaolou structures (unreinforced and carbon-fiber cloth-reinforced) in an earthquake is studied by a physical model test. The results show that carbon-fiber cloth can effectively improve the seismic capacity. The natural vibration period and acceleration- and displacement-increment coefficients of DF and CDF conformed to the exponential law. The damage process can be divided into three stages: DS, YS, and PS. After reinforcement, the development law of the average value of the acceleration-increment coefficient changed from the N type to the V type, and the development law of the average value of the displacement-increment coefficient changed from the concave type to the V type. The Diaojiaolou was the least affected by the acceleration at I. The displacement deformation of DF was the least affected by the seismic waves at DZ1. The displacement deformation of CDF was the least affected by the seismic waves at I. These findings provide a theoretical basis for the seismic design of mountain Diaojiaolous.

Given the acceleration of urbanisation processes, urban lands have nearly become saturated, and the gap between population and land is increasing. The development of underground spaces has become important for solving the three major crises of urban population, resources, and environment and is a critical step in the sustainable development of cities. Therefore, the effects of the excavation method and drag-and-replace on underground storey supplementation of 3 × 3 frame structures having different foundations were investigated in this study through model tests and numerical simulations. The results show that removal of the top slab in the concentric square slab tray replacement produces the most unfavourable working conditions when the foundation is independent. In cruciform slab draglines, uneven settlement of the non-equal-span frame structures is greater than that of equal-span frame structures, and the final settlement is positively correlated with the span size. The central shaft and surround-island-type soil excavation methods are more effective when applied to free-standing foundations. Deformation of the strip foundation in the pile-wall type of buttress is mainly concentrated in the contact area with the buttress pile and middle area of the frame. The ring-shaped reserved core soil body earth excavation method is more effective for layered excavation in the buttressing of strip foundation piles. Based on these findings, corresponding measures are proposed for use as project references.