This paper uses a simplified assessment method based on the excavated-induced ground movement to examine the coupling effect between adjacent excavations during construction. The finite element numerical model is established to simulate and analyze the deformation of adjacent excavations at each stage of construction. Distinct construction sequences are employed to explore the dissimilarities in the deformation characteristics of the surrounding soil and envelope after excavation. The results indicate that when adjacent excavations are excavated simultaneously, their interactions affect the soil and envelopes' deformation. The maximum ground settlement occurs at a certain distance from the edge of the excavation. As the excavation depth increased, the enclosure exhibited a more pronounced deformation. The deformation of the enclosure structure can be significantly inhibited by the spatial effect at the corners of the excavation. When adjacent pits are constructed in different construction sequences, the enclosure structure on the first constructed excavation often experiences greater deformation than on the later constructed excavation.

In soft soil regions, the construction of irregular-shaped excavations can readily disturb the underlying soft clay, leading to alterations in soil properties that, in turn, cause significant deformations of the excavation support structure. These deformations can compromise both the excavation's stability and the surrounding environment. Based on a large-scale, irregular-shaped excavation project for an underground interchange in a soft soil area, numerical simulations were performed using Midas GTS to analyze the overall foundation pit deformationn. The study explored the effects of groundwater lowering, excavation, and local seepage on the disturbance of surrounding soils and the resulting foundation pit deformationn. The findings reveal that the irregular-shaped excavation exhibits distinctive spatial deformation characteristics, with the arcuate retaining structure's arching effect reducing the diaphragm wall's horizontal displacement. Groundwater lowering exerts a stronger disturbance on shallow soils near the excavation and a weaker disturbance on deeper soils. Excavation-induced stress redistribution notably affects the soils above the excavation surface and those within the embedded region of the support structure. Local seepage primarily disturbs the soils surrounding the leakage point. Additionally, the weakening of soil parameters significantly influences the foundation pit deformationn. Combined disturbance (dewatering + excavation + leakage) induced 32%, 45%, and 58% greater displacements compared to individual factors, confirming the critical role of multi-factor coupling effects.

The continuous demand for urban development, along with the construction of new buildings, highways, and infrastructure, creates an increasing necessity for excavation activities. Deep excavation near existing buildings can lead to ground instability, potentially causing structural damage to nearby properties. This research aims to investigate methods for enhancing buildings stability from the initial stages of construction, focusing on protecting structures from potential future adjacent excavations. This study utilizes a skirt-raft foundation system, modeled using the finite element software PLAXIS 3D, to evaluate its effectiveness in improving stability and protection. The study analyzed the behavior of raft foundations in clay soil adjacent to excavations ranging from 1 m to 10 m and compared this with the performance of raft foundations with added skirt foundations. The comparison focused on settlement, rotation, and lateral movement of the excavations to assess potential building damage. The results showed that incorporating a skirt foundation significantly enhanced structural stability and reduced excavation-related damage. The implementation of a skirt foundation to a depth of 0.5B (where B is the foundation width) for excavations of similar depth has been shown to significantly reduce damage levels from medium or high to light while also decreasing differential settlement by 80%. It is recommended that adjacent excavation depths should not exceed 0.25B. However, if a skirt foundation is constructed at a depth of 0.5B, the excavation depth can be safely extended to 0.75B.

This research examines the relationship between excavations and tunnel responses, emphasizing the influence of geometric factors on tunnel heave. Utilizing an exponential correlation between heave and unloading ratio, the study investigates into stress changes with increasing excavation depth. Maintaining a constant axial horizontal distance proves crucial for stable tunnel responses. FLAC3D numerical modeling highlights increased stress-strength ratios near excavations, impacting the tunnel crown. Water ingress induces soil consolidation, leading to additional deformations, while adverse excavation conditions can cause leaks, dislocations, and cracks in the tunnel lining. The study also analyzes rock behavior under diverse loading and excavation conditions, revealing stress point relationships with the yield surface in principal stress space.

Recently, the application of Bayesian updating to predict excavation-induced deformation has proven successful and improved prediction accuracy significantly. However, updating the ground settlement profile, which is crucial for determining potential damage to nearby infrastructures, has received limited attention. To address this, this paper proposes a physics-guided simplified model combined with a Bayesian updating framework to accurately predict the ground settlement profile. The advantage of this model is that it eliminates the need for complex finite element modeling and makes the updating framework user-friendly. Furthermore, the model is physically interpretable, which can provide valuable references for construction adjustments. The effectiveness of the proposed method is demonstrated through two field case studies, showing that it can yield satisfactory predictions for the settlement profile. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).