Permafrost, a critical global cryospheric component, supports subarctic boreal forests but is frequently disturbed by wildfires, an important driver of permafrost degradation. Wildfires reduce vegetation, organic layers, and surface albedo, leading to active layer thickening and ground subsidence. Recent studies using interferometric synthetic aperture radar (InSAR) have confirmed the rapid and extensive post-fire permafrost degradation, and have largely focused on short-term impacts. However, the longer-term post-fire permafrost deformation, potentially persisting for decades, remains poorly understood due to limited data. Here, we applied InSAR in North Yukon to detect deformation signals across multiple fire scars in the past five decades. Using a chronosequence (space-for-time substitution) approach, we summarize a continuous trajectory of post-fire permafrost evolution: (a) an initial degradation stage, characterized by abrupt subsidence up to 50 mm/year and gradually slowing over the first decade, with cumulative subsidence exceeding 100 mm locally; (b) an aggradation stage from approximately 15 to 30 years after fire, marked by ground uplift reaching 25 mm/year before gradually declining, compensating for the earlier subsidence; and (c) a stabilization stage beyond three to four decades, where permafrost nearly recovers to pre-fire conditions with indistinguishable deformation between burned and unburned areas. Notably, the rarely-reported uplift phase appears closely related to vegetation regeneration and fire-greening feedback that provide thermal protection, suggesting a critical mechanism of permafrost recovery. These findings provide new insights into the resilience of boreal-permafrost systems to wildfires and also underscore the importance of long-term InSAR monitoring in understanding permafrost responses to wildfires under climate change.

Underground mining exploitation causes deformations on the ground surface as a result of the filling of the resulting voids. In certain situations, apart from mild continuous deformations, discontinuous deformations may occur in the form of, e.g., steps in the ground. Unexpectedly occurring discontinuous deformations cause significant damage to buildings protected against the influence of continuous deformations, but do not lead to their complete destruction. For this reason, the aim of this paper is to present a numerical analysis of such an impact case, which, on the one hand, is sufficiently accurate and reflects the behaviour of the real structure, and on the other hand, it will be a guide for experts who will aim to determine the safety of similar structures. In the presented case, the multiple longwall mining of coal ended in the same place resulting in the formation of a step in the ground about 15 cm high under a residential building. Not protected building against such deformations, suffered significant damage. The numerical analysis of the residential building was carried out with the advanced ATENA software package. In order to accurately represent the building and the impacts, the structure and the surrounding ground were modelled. The structure of building and the ground were modelled with tetrahedron- and hexahedral-shaped volumetric elements. On the contact surface of the structure elements and the ground, flat contact elements were used. The loads on the structure were introduced in the form of displacements caused by the appearance of a terrain threshold. The results of numerical calculations are presented in the form of color stress maps. The obtained calculation results are very close to the actual damages, which confirms the correctness of the analysis.

The shutdown of earth pressure balance (EPB) shield tunneling in gravel stratum can easily lead to significant unexpected ground deformation. In order to study the response of gravel strata during shield shutdown and the characteristic change of soil state in the chamber, this paper establishes a coupled Eulerian-Lagrangian finite element method (CEL-FEM) coupling analysis model that reflects the interaction between the spoiled soil and gravel strata. The plastic flow parameters of CEL spoiled soil are calibrated using the slump method, and a quantitative relationship between the slump value, plastic flow parameters, equivalent coefficient of loosening, and excavation face support pressure is established. The reliability and applicability of CEL method in the simulation of shield shutdown are verified by the field measurements. Results show that: (1) The chamber's soil equivalent loose coefficient is inversely proportional to the soil slump value which is related to soil's plastic flow parameters. (2) The shield shutdown in gravel strata has a more significant impact on the deep strata displacement than on the surface. (3) During the shield shutdown stage, the chamber pressure should be dynamically adjusted based on the soil deformation characteristics, and an increase of 16% could result in a stable rebalance.

The deformation caused by tunnel excavation is quite important for safety, especially when it is adjacent to the existing tunnel. Nevertheless, the investigation of deformation characteristics in overlapped curved shield tunneling remains inadequate. The analytical solution for calculating the deformation of the ground and existing tunnel induced by overlapped curved shield tunneling is derived by the Mirror theory, Mindlin solution and Euler-Bernoulli-Pasternak model, subsequently validated through both finite element simulation and field monitoring. It is determined that the overcutting plays a crucial role in the ground settlement resulting from curved shield tunneling compared to straight shield tunneling. The longitudinal settlement distribution can be categorized into five areas, with the area near the tunnel surface experiencing the most dramatic settlement changes. The deformation of the existing tunnel varies most significantly with turning radius compared to tunnel clearance and grouting pressure, especially when the turning radius is less than 30 times the tunnel diameter. The tunnel crown exhibits larger displacement than the tunnel bottom, resulting in a distinctive 'vertical egg' shape. Furthermore, an optimized overcutting mode is proposed, involving precise control of the extension speed and angular velocity of the overcutting cutter, which effectively mitigates ground deformation, ensuring the protection of the existing tunnel during the construction. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published 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 Taiwan Ground Deformation Index (TGDI) is proposed to quantify site vulnerability using a non-linear soil deformation model, PGA parameters from the Taiwan seismic intensity scale, and microtremor analysis. Site vulnerability is graded into four levels: low (TGDI = 7.4), based on susceptibility to seismic damage. Validating TGDI with 13 disaster events in Tainan during the 2016 Meinong earthquake showed 12 cases of moderate-to-high vulnerability. Since weak ground and strong amplification properties favor TGDI increases, this index serves as an early warning parameter for disasters.

Purpose: The study aims to investigate the behavior of buried steel pipelines in different layouts under the influence of various permanent ground movements that may occur as a result of earthquakes. In addition, different factors such as pipe diameter, pipe material properties, burial depth, and lateral earth pressure were varied to form 8 different analysis groups to determine their effects on the performance of pipelines. The results will contribute to the practical design and preliminary evaluation of the pipelines by the operating institutions. Theory and Methods: The effects of 10 different axial ground motion lengths, 9 different ground displacements, 8 different pipe layout models and 16 different variables (e.g. burial depth) were evaluated by finite element analyses. In order to observe the interdependent effects of the changes, analyzes were carried out by considering over ten thousand combinations. Results: The effects of the length of the PGD zone and the amount of displacement on pipeline behavior are assessed relative to boundaries (Fig. A) for different pipeline layouts. Moreover, the effects of the investigated variables on pipe stress and strain are explained one by one in the study. Conclusion: The effect of variables such as burial depth and pipe material properties on the analysis results varies depending on pipeline layouts and other parameters such as displaced ground block length and displacement amounts. Contributions of all these factors on pipeline performance are explained in detail to provide guidelines for the design and preliminary evaluation of the pipelines by institutions which operates the systems.

This paper presents observed arching-induced ground deformation and stress redistribution behind braced excavation using the top-down construction method. The soil properties around the excavation were determined by laboratory and field tests. The ground deformation, soil displacement vector, strain path, principal strain, maximum shear strain, lateral earth pressure, pore water pressure, and effective stress path are presented based on the measured data. The majority of soil behind the wall is under volumetric expansion, indicating consolidation, creep behavior, or a combination of both. Besides, two periods of increases in pore pressure are observed, due to stress transfer from the lower to the upper parts (i.e., soil arching effect). The deep inward movement of the wall and the nearby soil accounts for the distribution of lateral earth pressure acting on the wall. The soil located behind the area of maximum wall deformation and adjacent to the wall, as well as the soil below the excavation base intersected by the shear plane, is in an active stress state. The lateral earth pressure at 5 m from the left excavation wall showed minimal changes, due to the combined effects of soil arching from lateral excavation and shield tunneling.

Two disastrous earthquakes, named Pazarc & imath;k (Mw7.8) and Ekin & ouml;z & uuml; (Mw7.6), occurred on February 6, 2023 in the southeast part of T & uuml;rkiye and were collectively named Kahramanmara & scedil; earthquakes. These seismic events were caused by a left lateral strike-slip faults, and resulted in significant loss of life, severe damage to infrastructures and buildings, and geotechnical damages such as mainly large-scale slope failures, rockfalls, and ground liquefaction. The main goal of this study is to assess the extend and impact of widespread ground liquefaction, particularly on built environment. Additionally, the ranges of amount of settlement and tilting of buildings due to ground liquefaction were briefly discussed and liquefaction caused by Kahramanmara & scedil; earthquakes were compared with those others occurred in T & uuml;rkiye. The site observations indicated that except a village, a short of a highway, a few bridges and two settlements, widespread liquefaction was mainly observed in agricultural non-urbanized fields. The maximum amount of settlement at some liquefaction locations reached up to 2 m and high-raise buildings tilted 7-8 degrees from the vertical reaching up about 20 degrees. Observations indicated that single-storey and two-storeys buildings with a basement to a certain depth, a lower center of gravity and raft foundation should be considered suitable on soils susceptible to liquefaction in earthquake-prone regions without taking any counter-measures against ground liquefaction. Mass movements along the shoreline of the G & ouml;lba & scedil;& imath; Lake were unlikely to be caused by lateral spreading resulting from ground liquefaction and they were rather due to planar sliding along a weak layer dipping towards the lake with progressive failure.