During the construction of a shield tunnel, it will disturb the surrounding ground and affect the use and structural safety of buildings around the tunnel. The geometric parameters of the tunnel, the operating parameters of the shield machine, and the geological parameters will affect the degree of disturbance. However, the existing theories and models are difficult to comprehensively consider the interaction of these factors, and it is difficult to accurately predict the response of the formation to solve the above problems. The research is based on the machine learning algorithm to establish a prediction model of stratum settlement caused by shield tunneling, which provides a new idea for real time prediction of the ground response caused by shield tunneling and risk reduction. The main results of this research are as follows: (1) propose a novel quantification method for geological parameters that can comprehensively consider the physical and mechanical properties of the rock,soil layers, and the geometric characteristics of depth and thickness and (2) establish a more robust proxy model and use the k-fold cross-validation method to enhance its performance.

The excavation of the deep foundation pit of subway station may cause excessive deformation of foundation pit and retaining structure and then pose a threat to the safety of surrounding buildings and people. Therefore, it is necessary to analyze the characteristics of ground settlement and lateral displacement of the retaining system of foundation pit caused by deep foundation pit excavation in the Guangzhou composite stratum. Based on 28 subway station projects in Guangzhou, this paper analyses the monitoring data in the process of deep foundation pit excavation and reveals the deformation characteristics of subway deep foundation pit in the Guangzhou composite stratum. The research results can provide data support for the excavation scheme design and environmental control of similar deep foundation pit projects. The results show that: (1) The final deformation of the foundation pit at Guangzhou Metro Station is predominantly within the range of 5 to -15 mm. Monitoring points with settlement values exceeding 30 mm constitute the smallest proportion, while only a limited number of measuring points exhibit surface uplift. The observed ground uplift can be attributed to two primary causes: basement heave and the infiltration of grouting slurry outside the pit. (2) The maximum ground settlement of foundation pit increases with the increase of excavation depth. When the aspect ratio of foundation pit is greater than 15, the maximum ground settlement has an obvious positive linear relationship with it. The insertion ratio of foundation pit retaining structure in the Guangzhou area is mainly concentrated in 0.30-0.59, with an average value of 0.42, and the maximum ground settlement gradually decreases with the increase of insertion ratio. (3) The maximum lateral displacement of the retaining structure of the foundation pit accounts for the largest proportion in the range of -20-25 mm. The maximum lateral displacement of the retaining structure increases with the increase of the excavation depth and the length-width ratio of the foundation pit. The maximum lateral displacement of the retaining structure decreases with the increase of the insertion ratio. There is an obvious skirting phenomenon in the granite residual soil foundation pit. Attention should be paid to and the insertion ratio should be appropriately increased in the project. (4) The maximum ground settlement caused by deep foundation pit excavation of a subway station in the Guangzhou area is 0.99-1.90 times of the lateral displacement of foundation pit retaining structure.

Mumbai is an elongated island city and spreading towards northern side as the southern side is sea face. Mumbai Metro Line 3 (MML-3) project corridor from Colaba to Seepz, is fully underground metro of a total length 33.5 km twin tunnel. In this project, 17 nos. of TBMs deployed to construct the tunnel. The tunnel is excavated through Basalt underlying filled up material and soil strata (sandy and clayey). A systematic instrument arrays are installed along the tunnel alignment to monitoring at the ground, on the ground and in the tunnel, existing buildings along the tunnel alignment in the influence zone (both side of tunnel alignment) as per monitoring scheme. Monitoring of instruments was done as per the frequency required for tunnelling activities based on the excavation stages and to acquire the recorded data. Based on the monitoring data and their interpretation, design modification has been done to achieve safe tunnelling which is the first and foremost requirement in urban tunnelling. This paper highlights the surface settlement at the ground surface and in the tunnel excavated zone due to tunnelling.

A pipeline with long-term hidden leakage will greatly reduce the stability of the ground between the pipeline and tunnel in the process of tunneling through existing pipelines in unsaturated soil. Excessive settlement of the surrounding strata and pipelines can occur when the shield excavation face approaches below a pipeline, which can lead to engineering accidents. This study is based on a self-developed model experimental system for tunneling through an existing pipeline with a double-line tunnel shield. The ground settlement and pipeline deformation caused by shield construction with small-scale and no leakages are investigated. An experimental study is conducted and the accuracy of the results is verified through a comparison with theoretical solutions. The results demonstrate that there is a significant increase in ground settlement and pipeline deformation under the influence of leakage water. It is also determined that the displacement field generated by the excavation of a double-line tunnel is not simply a superposition of the displacement field generated by the excavation of a single-line tunnel. The repeated disturbances caused by the excavation of a double-line tunnel significantly influences the redistribution of the displacement field. Additionally, a three-dimensional (3D) model of shield construction considering the influence of pipeline leakage is established. This study discusses the ground settlement and pipeline deformation patterns caused by changes in the vertical and horizontal leakage diffusion ranges. The computational results indicate that the diffusion depth of a leakage is the primary factor controlling the extent of settlement.

In the present study, four different SPT-based methods for liquefaction assessment namely Seed and Idriss (S-I), Tokimatsu and Yoshimi (T-Y), Japan Road Association (JRA), and Chinese code for Seismic Design of Buildings (CSDB) method has been discussed in detail. The present study compares the liquefaction potential estimation of S-I, T-Y, and JRA methods, respectively. The S-I method predicts 9.29 and 3.42 times higher liquefaction occurrence compared to JRA and T-Y methods respectively. Different damage indices such as liquefaction potential index (LPI), liquefaction risk index (LRI), and ground settlement have been evaluated for an earthquake magnitude of 7.5 on the Richter scale and peak ground accelerations varying in the range of 0.1-0.36 g respectively. LRI provides a more precise estimation of the liquefaction damages compared to LPI. The gradation of liquefiable soil has been presented and compared with the established limits of liquefiable soils.

Climate warming is causing significant changes in the Arctic, leading to increased temperatures and permafrost instability. The active layer has been shown to be affected by climate change, where warmer ground surface temperatures result in progressive permafrost thaw and a deepening active layer. This study assessed the effects of thermal modeling parameters on permafrost ground response to climate warming using the fifth phase of the Coupled Model Intercomparison Project (CMIP5) and TEMP/W software. We analyzed how variations in depth, water content, and soil type affect predictions of future active layer depths and settlement under various climate scenarios using the soil characteristics along Hudson Bay Railway corridor. The results indicate that, for finegrained soils, the depth of the model is a more significant parameter than for coarse-grained soils. The water content of all soil types is a critical factor in determining the time at which permafrost thaws and the depth at which the active layer is located, as higher water content leads to larger active layer changes and more settlement in most cases. Our findings have important implications for infrastructure and land use management in the Arctic region.

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/).

The current analytical solutions for predicting the ground settlements induced by small curvature tunneling in soft ground are generally conducted on the assumption of linear elastic foundation and provide little attention on the soil rheology. This paper introduces a mathematical model to estimate the small curvature tunneling induced adjacent ground settlement considering the soil viscoelasticity. By introducing the Boltzmann viscoelastic ground model under the Laplace transform, the time domain parameters converted from Poisson's ratio and shear modulus are derived to further obtain the viscoelastic ground loss solution and the Mindlin solution. Then, the proposed viscoelastic solutions are employed for the ground settlement caused by the overexcavation and imbalanced loads for the small curvature tunnel, which accounts for the soil rheology influence. The accuracy of the mathematical model is then verified by comparisons with in-situ observed data and 3D numerical simulation results, as well as good agreement is obtained. Finally, the parametric analyses are performed to estimate the influence for transverse and longitudinal surface settlements, including tunnel curvature radius, shield cutterhead face radius, over-excavation value, creep time and shear modulus ratio of viscoelastic ground.

Global warming of 2 degrees C above preindustrial levels has been considered to be the threshold that should not be exceeded by the global mean temperature to avoid dangerous interference with the climate system. However, this global mean target has different implications for different regions owing to the globally nonuniform climate change characteristics. Permafrost is sensitive to climate change; moreover, it is widely distributed in high-latitude and high-altitude regions where the greatest warming is predicted. Permafrost is expected to be severely affected by even the 2 degrees C global warming, which, in turn, affects other systems such as water resources, ecosystems, and infrastructures. Using air and soil temperature data from ten coupled model intercomparison project phase five models combined with observations of frozen ground, we investigated the permafrost thaw and associated ground settlement under 2 degrees C global warming. Results show that the climate models produced an ensemble mean permafrost area of 14.01 x 10(6) km(2), which compares reasonably with the area of 13.89 x 10(6) km(2) (north of 45A degrees N) in the observations. The models predict that the soil temperature at 6 m depth will increase by 2.34-2.67 degrees C on area average relative to 1990-2000, and the increase intensifies with increasing latitude. The active layer thickness will also increase by 0.42-0.45 m, but dissimilar to soil temperature, the increase weakens with increasing latitude due to the distinctly cooler permafrost at higher latitudes. The permafrost extent will obviously retreat north and decrease by 24-26% and the ground settlement owing to permafrost thaw is estimated at 3.8-15 cm on area average. Possible uncertainties in this study may be mostly attributed to the less accurate ground ice content data and coarse horizontal resolution of the models.